 Tuberculosis has plagued humanity for thousands of years. Dr. Robert Koch identified the bacterium that causes TB in 1882. But another 70 years would pass before this important discovery would lead to a cure. At its peak at the turn of the century, TB was the leading cause of death in the United States, killing one out of every four people. Popular remedies ranged from tonics laced with opium to sulfuric acid applied to the chest. For many years, patients were placed in sanatoria where the only treatments available were rest and fresh air. Real progress in the fight against TB did not arrive until after World War II, when general public health conditions improved and effective chemotherapies such as streptomycin and isoniazid were discovered. After decades of decline, TB was thought to have been conquered. As a result, TB programs lost funding in the 1970s and 1980s. But by the late 1980s, TB was on the rise again, with more than 26,000 cases reported in 1992. Several factors were behind the resurgence of TB. Chief among those was a change in social conditions that resulted in a number of people being homeless, people being crowded in shelters, in addition, the occurrence of HIV infection. And perhaps most important of all was the deterioration in the public health infrastructure and in the control programs that to that point had been quite successful in bringing tuberculosis to very low rates in this country. To regain control of the disease, Congress increased funding for TB programs in the early 1990s. These programs made tremendous strides and annual TB cases fell 31% between 1992 and 1998. But while the overall incidence of TB in the U.S. is falling, rates of TB in certain groups remain alarmingly high. They tend to be the groups that are socially the most marginated, homeless persons, persons with substance abuse problems, HIV infected persons, persons from countries where there's a high prevalence of tuberculosis. Internationally, TB continues its deadly rampage. According to the World Health Organization, one third of the world's population is infected with the tuberculosis bacillus, with 7 to 8 million people developing the disease each year. TB accounts for more than one quarter of all preventable adult deaths in developing countries. We can expect that in the next 20 years, nearly 1 billion more people will become infected. 200 million people will develop the disease and 70 million people will die from TB if global control is not strengthened. Multi-drug resistant TB is now found on five continents. One of the most effective strategies against TB is Directly Observed Therapy, or DOT. That involves, as the name would imply, a healthcare worker directly observing the patient taking the medications. Another effective strategy is screening high-risk populations and increasing the number of people who receive treatment for latent infection. Despite recent gains in prevention and control, however, TB continues to be a major health threat. In order to win the war against TB, healthcare providers and public health workers need access to information, technical assistance, and training about TB control strategies. To provide these services, the Centers for Disease Control and Prevention established in 1993 three model centers, the Francis J. Curry National Tuberculosis Center in San Francisco, the Charles P. Felton National Tuberculosis Center at Harlem Hospital in New York City, and the New Jersey Medical School National Tuberculosis Center in Newark, New Jersey. Each year, the model centers train thousands of health providers and TB program staff to help them in the fight against tuberculosis. In 1995, the CDC's Division of TB Elimination produced five self-study modules on TB to provide basic information about TB to entry-level public health workers and others who serve persons with or at risk for TB. That year, the CDC also produced a satellite primer on tuberculosis, a national five-part satellite course based on the self-study modules that reach TB programs across the country. TB Frontmine continues this tradition of excellence. This three-part course is based on four new self-study modules developed by the CDC, covering contact investigation, confidentiality, surveillance and case management in hospitals and institutions, and patient adherence. TB Frontmine is brought to you by the Francis J. Curry National Tuberculosis Center in collaboration with the Division of Tuberculosis Elimination, National Center for HIV, STD and TB Prevention, Centers for Disease Control and Prevention, the Charles P. Felton National Tuberculosis Center at Harlem Hospital, the New Jersey Medical School National Tuberculosis Center and the Public Health Training Network. Hello and welcome to TB Frontmine. I'm David Satcho, Assistant Secretary for Health and Surgeon General. In the last few years working in partnership, we've gained important ground in the fight against tuberculosis. The incidence of TB cases in the United States has steadily declined. However, much work remains to be done if we're to continue these downward trends. We must remember that about 3 million people die of TB each year worldwide, and that many cases in the United States result from travel to and from other countries. Our shared goal is to achieve the eventual elimination of TB in the United States. TB Frontline is an important collaboration in this effort between the Francis J. Curry National Tuberculosis Center and the Centers for Disease Control and Prevention's Division of Tuberculosis Elimination and Public Health Training Network. To the thousands of health care staff who are watching from health departments, VA hospitals, correctional institutions and other facilities, we salute you for your diligence and dedication on the frontlines of TB prevention and control. Thank you for your participation today. Welcome to TB Frontline, Satellite Primer Continued, Modules 6-9. I'm Dr. Gisela Schechter of the Francis J. Curry National Tuberculosis Center, and I'll be moderating this three-part course. We're broadcasting live from San Francisco, California to over 7,000 of you who work on the frontlines of TB control. Across the country in all 50 states and Canada, this program is being shown at over 900 downlink sites. You are gathered in health departments, hospitals, libraries, colleges, universities, prisons and jails. We thank the site coordinators who are managing course logistics at each downlink site and making it possible for us to reach so many of you. If you registered for the course with the TB Frontline office by the registration deadline last December, you should have received a set of the four self-study modules upon which this course is based. If you were unable to register for the course last December and would like to order the modules, we will provide ordering information at the end of today's program. Please be sure to read the module that corresponds to each course session before that week's broadcast. During the upcoming satellite sessions, we will review information in these modules, illustrate their application to the public health setting, and present case studies along with graphics and video. Today, we begin with part one of TB Frontline. This two-hour session is based on module number six and will focus on contact investigation in tuberculosis control. I'd like to introduce our faculty members for this session. Dr. Paula Fujawara is assistant commissioner and director of the TB control program for the New York City Department of Health. Brenda Ashkar is nurse manager for the Los Angeles County TB control program. We will hear presentations from both Dr. Fujawara and Mrs. Ashkar on various aspects of contact investigation. We will also apply the course content to case studies based on real-life patients. We will conclude our broadcast with a question and answer period. Right now, let's hear TB control staff from San Francisco asking the questions that we plan to address in today's broadcast. When should a contact investigation be done? What are the steps of a contact investigation? What are the factors that affect the risk of transmitting tuberculosis? Which contacts should I consider a high priority? What is the concentric circle approach to contact investigation? Thanks to our San Francisco TB control staff for asking those important questions that a contact investigation needs to answer. Contact investigation is certainly one of the most challenging aspects of any TB control program. Let's start off our exploration of this important topic with part one of a two-part presentation by Dr. Fujawara. Thank you. Today we will be discussing one of the most important TB control activities, the contact investigation. We will be reviewing what a contact investigation is to whom we should target contact investigations for not everyone has the same risk of being infected and therefore investigated. Why a contact investigation is important, the concept of an index versus a source case, how a contact investigation is performed and how we evaluate if the contact investigation was done well. First, what is a contact investigation? This is a procedure to identify people who are exposed to an individual with infectious TB disease to evaluate them for either latent TB infection or LTBI and TB disease and to provide appropriate treatment for those with either TB infection or disease. Why is it so important to perform a contact investigation? Broadly, a contact investigation can be thought of at two different levels. First, there's a responsibility to the community, usually through its health department, to protect the health of the community by identifying its cases of tuberculosis disease in order to prevent the spread of TB infection and additional TB disease. Second, we want to protect the health of the individual. A contact investigation is important to find contacts who have TB disease so they can be given treatment and stop the chain of further transmission. Have latent TB infection so they can be given treatment for LTBI, are at high risk of developing TB disease and may need treatment for LTBI until it becomes clear whether they have TB infection. But why are we concentrating on contacts? Are contacts at high risk of developing TB disease or infection? Yes, contacts are at high risk of developing TB disease or infection. The rate of having TB disease is 75 times higher among contacts than among the general population. Since some contacts develop TB disease before the contact investigation is started, performing a contact investigation is one of the best ways to find people who have TB disease. An important goal is to find infected contacts before they develop TB disease so they can be treated for latent TB infection. On average, about 20% of contacts are found to have TB infection, but in some contact investigations as many as 80 to 100% may be infected. Certain contacts are at very high risk of developing TB disease if they are infected. These include children who are younger than 4 years of age, are immunosuppressed especially if infected with a human immunodeficiency virus or have certain medical conditions which will be discussed later. How do we know when to perform a contact investigation? Communities have laws that require the reporting of persons with suspected or confirmed TB disease to the local health department. The initial case reported to the health department is called the index patient. He or she is the one who alerts the health department that TB is present in the community. We'll be addressing this important concept later in this program. Remember the reason we are performing an investigation of close contacts to individuals with infectious TB disease. We do this in order to identify those who have become infected with mycobacterium tuberculosis including others who also have tuberculosis disease and ensure that they begin and complete a full course of treatment whether for infection or disease. But should a contact investigation be performed on everyone who has been reported to the health department? No. A key concept is that certain contacts have a higher priority for investigation than others. How do you decide, especially if you have more than one case that's been reported in the last few days and you have a limited number of staff to perform the investigations? In general, a contact investigation should be done whenever a patient is found to have or suspected of having infectious TB disease. How do we know if someone is infectious? One key concept is the sight of disease. Those with TB in the lungs or the larynx, also called the vocal cords, have the potential to be more infectious than someone who has TB in a site outside of the lungs or larynx such as the kidney, lymph node, or bone. Even those with pulmonary or laryngeal TB do not have the same level of infectiousness. Infectiousness is more likely when patients have cough, hoarseness, and other symptoms of pulmonary or laryngeal TB. Other factors that increase the likelihood of infectiousness include a positive AFB sputum smear or culture results, a cavity on the chest radiograph, inadequate or no treatment, young children, even if they have TB in the lungs, are less likely to be infectious, usually because they do not have the strength to cough forcefully enough to expel the TB organisms into the air. However, a child is often a trigger for a source case investigation, which will be described later in this program. Thus, a key concept is our ability to prioritize contact investigations. Why are we emphasizing the concept of prioritizing the work of finding contacts? We want to find the contacts that matter. Some people think, if I can find the five contacts per case that my supervisor says is the program's goal, I'll be okay. However, it is more valuable to the goals of tuberculosis control to find two contacts who have TB disease or infection so they can be treated than to find 50 people who happen to be in the same room for only a few minutes with someone with tuberculosis disease. Decisions about the prioritization of contact investigation should be made by supervisory, clinical, and management staff. The principles are, first investigate individuals with pulmonary or laryngeal disease who have a positive AFB sputum smear. TB cases with pulmonary or laryngeal disease with negative AFB sputum smears are a lower priority than those with positive smears. However, a contact investigation for negative smear cases usually should be conducted. Some individuals, when they hear that they have a negative AFB smear, believe that they do not have TB disease. However, even if the smear is negative, the culture may be positive for them tuberculosis, which implies infectiousness, although probably at a lower level than someone who has a positive smear. How well the specimen was collected may also affect if the smear is negative or positive. Since people with extra pulmonary TB only, that is TB outside of the lungs, do not carry any risk for transmission, contact investigations are not performed. Likewise, persons with non-tuberculous mycobacteria such as MAVM complex should not be investigated since non-tuberculous mycobacteria are not spread from person to person. In some instances, since non-tuberculous mycobacteria cause a positive acid fast bacillus smear, a contact investigation is initiated before the culture results are available. However, once the cultures reveal only non-tuberculous mycobacteria and the patient has been evaluated clinically to rule out TB disease, the contact investigation is usually stopped. How quickly should a contact investigation be initiated? The contact investigation should be initiated no more than three working days after the case is reported to the health department. Close contact should be examined within seven working days after the index case has been diagnosed. By working quickly, we can break the chain of transmission of tuberculosis disease. Timeliness is especially crucial for some high-risk contacts such as young children, HIV infected and other immunosuppressed contacts since they have the potential to develop TB disease very quickly after being exposed to infected with M tuberculosis. In addition, the more time elapses, the more difficult it may be to locate some contacts. Homeless individuals can move from shelter to shelter. Although people who move out of the state can be referred through an established interstate mechanism, some individuals move out of the country. It may be extremely difficult to track them down. One key concept is the difference between an index case and a source case. The term index case refers to the first case reported to the local health department. However, this person may not have started the chain of transmission of TB disease. That term is reserved for the source case. As an example, we may first identify a baby with TB meningitis as the index case. However, the source may be his uncle with pulmonary tuberculosis who was living in the same house with the baby. In some instances, it is recommended to conduct a source case investigation to find the source of TB transmission when recent transmission is likely. This is usually done when a young child is found to have TB infection or disease and the age cut-off differs in different communities and the decision depends on the yield from prior investigations as well as the availability of staff to perform these investigations. A source case investigation is also done when a severely immunosuppressed person who does not have a known history of TB infection is found to have TB disease. Was the person recently released from a hospital where infection control procedures were lacking? Did she live in a congregate setting where transmission was possible? A third reason to do a source case investigation is when a cluster of TB skin test conversions is found in a high-risk institution, for example, in a health care or correctional facility. The purpose of a source case investigation is to determine who transmitted mTuberculosis to the child, index patient, or persons in the cluster of skin test conversions. Whether this person is still infectious, whether the case of TB in this person was reported to the health department, or whether any others were infected by the source patient. Since contact investigations are done among those with close contacts to the infectious patient, it is natural to think of the home as a logical place to begin one. However, most people do not isolate themselves at home. They have friends, attend schools, and go to work. There are special challenges in performing school and workplace contact investigations. Panic and anger is common, rumors start to fly, and it may be difficult to determine which individuals had the closest contact to the infectious case. If possible, health department staff should work in cooperation with the management team. Educate classmates and work colleagues to quell anxiety, and maintain strict confidentiality, even to the point of interviewing and evaluating the source case, so as not to raise suspicions. Ms. Ashkar will discuss this in greater detail later. Let's apply some of Dr. Fujiwara's points about contact investigation by reviewing the following four short cases. These cases should help us determine when a contact investigation needs to be done. The first case is about a man named Yuri. Yuri is a 43-year-old man who immigrated to the United States from Russia nine months ago. He is currently unemployed but attending English language classes at a local adult school. Yuri lives with a group of friends who are also recent immigrants from Russia, consisting of four adults and two children sharing a small duplex. Yuri recently sought treatment at his neighborhood health clinic for a persistent, productive cough, fever, and weight loss. He is AFB sputum smear positive, and his culture is pending. His chest x-ray is abnormal, and he has started a four-drug regimen. Should a contact investigation be done for Yuri? Why or why not? So, should a contact investigation be done for Yuri? Absolutely. He has a positive AFB sputum smear, which indicates infectiousness. He's got the symptoms of tuberculosis, especially the persistent cough, and so he really falls into one of the highest priority groups for a contact investigation. Thank you. On to our next case. Carl is a 70-year-old retired man who volunteers at a soup kitchen run by his church. He lives alone in an apartment and often visits his daughter and grandchildren who live nearby. Carl's physician referred him to the health department after he complained of shortness of breath, a weak, non-productive cough, fatigue, and night sweats. His AFB sputum smear is negative with culture pending. He was started on a four-drug regimen. Should a contact investigation be done for Carl? Why or why not? Is Carl's case a higher or lower priority than Yuri's case for a contact investigation? Why? Should a contact investigation be done for Carl? Yes, in this case, even though the AFB sputum smear is negative, he does have symptoms consistent with tuberculosis. In addition, his physician felt strongly enough about the diagnosis that he started him on treatment. You know, even though his physician felt very strongly about the diagnosis, it would be very helpful to the health department staff to have his X-ray reading. Is Carl's case a higher or lower priority than Yuri's case for a contact investigation? Well, Carl's case is actually a lower priority for investigation because he does have a negative smear while Yuri had a positive AFB sputum smear. And so the negative smear usually indicates that he probably has a lower bacterial load. But we would use the concentric circle beginning with the closest contacts first and if there's no evidence of transmission then we would stop the investigation. Ready for another case? While conducting active surveillance in a laboratory, a health department worker comes across lab results for Laura, a 35-year-old woman whose cultures contained MAVM complex only. Laura has three children under the age of eight and works in a nursing home. Should a contact investigation be done for Laura? Why or why not? Should a contact investigation be done for Laura? No, she has MAVM complex which is a non-tuberculous mycobacteria which is not transmitted person to person. And now for our last case. Roberto is a seven-year-old child who has been diagnosed with TB meningitis. Roberto and his family immigrated from Mexico two years ago and live with extended family in a small house. Roberto's AFB smear is negative. He has started an appropriate treatment regimen for his disease. Should a contact investigation be done with Roberto as an infectious source? No, he does not have infectious tuberculosis. He has TB meningitis which is extra pulmonary tuberculosis. However, he is the index case. In other words, the first case that was reported to the health department. You know, a source case investigation is done for non-communicable TB cases and converters. And the reason is we need to find out who transmitted the organism to Roberto. Is his source case still communicable and if so, he's transmitting to others. And it also allows us to find out if this source case was reported to the health department. And so we should do a source case investigation. I'd like to remind you all that for your questions, our fax number is 415-626-3110. Dr. Fujiwara will now continue with part two of her presentation on contact investigation. There are many steps in a complete contact investigation. These include medical record review, patient interview, field investigation, risk assessment for MTB transmission, decision about priority of contacts, evaluation of contacts, treatment and follow-up of contacts, decision about whether to expand testing and evaluation of contact investigation activities. While the investigation does not always proceed in this order, it is important to be organized, have all the steps in mind, and the tools and resources available to do the job well. One of the first activities is to perform a medical record review. It is important to confirm the diagnosis for a person with a sputum smear positive for AFB could have a non-tubercular mycobacterium. Information needs to be obtained about conditions that increase the likelihood of infectiousness and thus the relative priorities of the contact investigation, including having the site of TB disease in the lungs or larynx. For example, an adult with TB disease of the bone does not need a contact investigation. Having a cough that produces a lot of sputum or hoarseness may indicate laryngeal disease. Having a positive AFB smear and or m tuberculosis in the culture also increases the likelihood of infectiousness. As does having a cavity on the chest x-ray, as this indicates advanced disease in many TB organisms. Or not having started treatment or only having recently started treatment. One needs to ask when the TB symptoms began and when treatment was started. This helps to delineate the period of infectiousness. Determining the period of infectiousness as accurately as possible helps you to focus contact investigation efforts on those individuals who were exposed while the patient was actually infectious. However, estimating the period of infectiousness can be difficult. It is usually estimated by determining the date of the onset of the patient's symptoms, especially coughing, estimating the period of infectiousness should be done by clinical and supervisory staff after complete assessment of the information available. The period of infectiousness ends when all of the following criteria are met. Symptoms have improved. The patient has been receiving adequate treatment for at least two to three weeks. The patient has had three consecutive negative sputum smears from sputum collected on different days. Let's say a law student was infectious during the month of December only and then begins appropriate treatment for TB the last week of December. He starts his new job at the law firm the following February. A new colleague at the law firm would not have to be concerned about being exposed to the patient. However, the patient's wife and children should be evaluated. How about the patient's family who attended the Christmas dinner with the patient for only an hour? They certainly had contact during the period of infectiousness so are potential candidates for investigation, especially if the closest contacts consisting of his wife and children are infected. The results of diagnostic laboratory tests need to be collected. The information collected during the review of the medical record can help to determine the relative priority of the contact investigation as delineated in table 6.2 in your materials. Recall that the initial interview should occur no more than three working days after the case is reported to the health department. Why? Because some people may already have disease and will need treatment. Also, contacts may be more difficult to locate as time goes by. Recall of events may be easier if closer in time. There are three main reasons to interview the patient for contact investigation. First, to find out more about the patient's symptoms to help determine the period of infectiousness. This is the concept of time. Second, to find out places where the patient spent time while he or she was infectious. And third, to identify the patient's contacts. This is the concept of person. Also, you want to obtain locating information for the contacts, again the concept of place. And also, to find out how often and how long the contacts were exposed to the patient while he or she was infectious. Again, the concept of time. Let's talk about each of these. With symptoms, the person should be asked about the presence of TB symptoms, especially coughing, and how long these symptoms have been present. Put yourself in the patient's shoes. If he or she has trouble remembering, have the patient relate the onset of symptoms to significant events in their lives, birthdays, holidays, or major news reports. If the patient gives permission, family members or friends may be interviewed to help estimate when the symptoms began. For places, the patient should be asked to identify all the places he or she has been since the onset of symptoms. When thinking about the different types of places where patients may spend most of their time, the places can be broken down in three categories. Household or residence, worker's school, leisure, or recreation environments. One of the easiest ways to do this is to ask the patient to go over his or her daily routine. Where does he work? Does he work at more than one job? How does he get to the job? Who are his friends and where do they meet? Is she a student? Does she have hobbies? Does he volunteer? His service is anywhere. Does she go to church? Has she been in jail? Is he homeless? Regarding contacts, nearly every TB patient has at least one contact. And for some people, the range can be from one to several hundred. Depending on living quarters, workplace, and other circumstances. When staff tell me that Mr. Jones has no contacts, which thankfully they rarely do, I always tell them, no man is an island. The situation may be that some patients may be reluctant to name contacts. The reasons vary. Some may not want to reveal their drug partners. Some people fear exposing friends and colleagues who are in the United States illegally. Others fear retribution and stigma if others found out they had TB. It is crucial to be sensitive to the patient's fears and to assure the patient that all information including the patient's name will be kept confidential. A special situation for confidentiality concerns may have to be put aside is in the event the patient has died or cannot be located before the contact investigation interview is initiated or psychologically unable to participate in a contact investigation interview. It is still important that a contact investigation be conducted to identify individuals who may have been exposed to TB. A friend or family member who is knowledgeable about the places where the patient may have potentially exposed others should be interviewed as a proxy for the patient. If the health care worker cannot locate the infectious patient but knows places where she used to reside frequent or work, if appropriate the management may have to be notified of the need to conduct a contact investigation. Health care workers need to seek the counsel of their supervisor or the TB controller to obtain approval to breach confidentiality. When organizing the contact investigation information it is important to have a detailed form to collect not only the information from the medical record review but from the patient interview. Contact investigations can require the worker to meet with the patient several times or record information from multiple points in time from placing the skin test to reading it to obtaining the chest x-ray, visiting the doctor, obtaining sputum, waiting for smear and culture results and starting medications. It can be difficult to remember all the information that must be obtained. Workers, even experienced ones, should use the patient interview checklist to help organize the information on symptoms, places and contacts. Most programs will utilize some type of contact investigation form to systematically collect the information. These forms will vary between programs but all should contain index patient identifying information, index patient medical information, contact identifying information and risk factors, and contact evaluation and follow-up information. An example of the key elements needed for the data collection forms is in table 6.3 of your materials. To summarize, performing the patient interview takes skill both technical and interpersonal. Of course, the interviewer has to know enough about TB disease and transmission to ask the appropriate questions, questions pertaining to symptoms, where the patient lived and spent time during the infectious period and which of the persons named are appropriate contacts. However, the manner in which people are asked often sensitive questions will impact on the quality and completeness of the answers or even if the question is answered at all. At all times, the patient should be reassured that his confidentiality will be assured. The field investigation is the time for the interview and education of close contacts about the purpose of the contact investigation, the basics of transmission, the risk of transmitting M tuberculosis to others, the importance of testing, treatment and follow-up for TB infection and disease. The visit is also an opportunity for observation and detective work. Additional contacts, especially children who may not have been identified during the verbal interview, may be uncovered. You can look for pictures of others who may live in or visit the house, shoes or others who live in the house or toys left by children. The environmental characteristics such as the size of the room, number of inhabitants and level of ventilation can be more fully assessed. Individuals may feel more relaxed and amenable to receiving TB education or tuberculin skin testing in their own home. A field investigation is also a time for caution. Workers should follow appropriate infection control guidelines including wearing a particulate respirator if the patient is infectious. Notifying your coworkers and supervisors of your whereabouts, using a buddy system when visiting a potentially dangerous area and wearing an identity badge are useful strategies. Finally, it is imperative to maintain patients' confidentiality. For example, health workers should put away stethoscopes, forms and medications when entering and leaving patients' homes. It is important to perform a risk assessment for TB transmission. Those of us experienced in tuberculous control issues know that some patients seem to infect everyone they come in close contact with while others seem not to infect anyone. The risk of transmission depends on three main factors. Infections of the TB patient, the environmental characteristics of each place, the characteristics of the high risk contacts. Infections of the person with TB depends on the period of time the patient was infectious, as well as the estimated degree of infectiousness estimating the period of infectiousness helps determine which contacts have actually been exposed to TB. For the second criterion, a person with a strongly positive AFB smear, a cough, and or cavatary tuberculosis is likely to be infectious. A person with extrapomyotuberculosis is not. Environmental characteristics are important. The risk of transmission in a particular place depends on the concentration of infectious droplet nuclei in the air. The greater the concentration of droplet nuclei, the more likely that TB organisms have been transmitted. This concentration depends on the size of the room with a small crowded room more likely to facilitate transmission compared to the large room that is not very crowded. The amount of ventilation with a poorly ventilated room more likely to facilitate transmission than a room with an open window in a breezy environment. The presence of air cleaning systems such as high-efficiency particulate air filters and ultraviolet lights to kill tubercle bacilli available in places such as hospitals and some clinics, correctional facilities, and shelters. This feature is only rarely available in a private home. If present, it has usually been placed there specifically to protect household contacts from becoming infected. High-risk contacts of certain characteristics, those who spend a lot of time with a patient, have been physically close to the patient or have shared a room or house are designated as close contacts and are at higher risk of becoming infected. Close contacts are not limited to those who live in the same household but include those who spend leisure, school, or work time with the patient. Notice that I didn't mention HIV or diabetes or certain other conditions causing immunosuppression as a risk for becoming infected. These people are at high risk for developing TB disease if infected but are not necessarily at risk for becoming infected in the first place. The concentric circle approach helps to make decisions about priority contacts. When a person with tuberculosis gives names of potential contacts, the worker must decide which, if any, are appropriate for testing. The key principle to keep in mind is the concentric circle. The concentric circle will be discussed in greater detail by Ms. Ashkar. Briefly, it is an approach to prioritize the evaluation of contacts. Obtaining a detailed history is crucial. We have already discussed the importance of asking patients about contacts in the different types of places where patients may spend most of their time, such as household or residence, worker school, leisure, or recreation environments. Sometimes health workers make the assumption that home contacts are the closest contacts, followed by work and leisure contacts. However, some people may spend equal amounts of time with each group. In contrast, a teenager may spend most of his time with his friends or in class and spend very little time at home. The most attention should be given to the contacts who are at most at risk of becoming infected or coming down with TB disease if infected. Those who are most likely to be infected are the close contacts who include people who have shared living quarters with the patient or spend time with the patient frequently during the period of infections. Contacts with less intense, less frequent, or shorter duration of contact to the TB patient are called other-than-close contacts, and they generally should be given a lower priority for testing. Sometimes it is difficult to accurately classify who is a close versus an other-than-close contact. Decisions about the prioritization of contact investigation should be made by supervisory and clinical staff. In the example of the teenager, even if he spends a lot of time with his friends, the classification of close versus other-than-close contacts can depend on the activity. Friends with whom he spends most of his time in a car with the windows rolled up are at much greater risk for becoming infected than the friends with whom he plays football on an open field. Similarly, at-school exposure to TB organisms may be greater for classmates with whom he sings in the choir than classmates with whom he has a class in a large lecture hall once a week. The other group of high priority contacts is those at high risk of developing disease if infected, such as young children, HIV-infected or immunosuppressed, and persons with certain medical conditions, such as certain types of cancer, diabetes mellitus, or body weight of 10% or more below ideal. As we have learned from Dr. Fujiwara, contact investigations require TB control staff to weigh many different factors when making decisions about how to proceed. To illustrate these factors, we'll now begin the story of Christine. This story is a dramatization based on a real-life case. Christine is a 17-year-old high school student originally from Vietnam. She and her mother have lived in this country for five years. On October 1st, Christine saw her private physician for persistent cough, fever, fatigue, and weight loss. The physician hospitalized her for diagnostic tests under respiratory isolation because her symptoms were worsening. A tuberculin skin test was placed and read two days later at 18 millimeters. Christine's chest x-ray showed an infiltrate in the right upper lung. Christine's sputum smears were positive for acid-fast bacilli. Later, when her culture results were returned, they indicated MTB, sensitive to all first-line drugs. She was started on four-drug therapy and was reported to the health department as a TB suspect. Two days after the report was made to the health department, a health care worker from the TB control program visited Christine for an initial interview, including questions about her contacts. What important information should be elicited from Christine at this point in the contact investigation? Well, we need to really think of ourselves as detectives. We need to ask ourselves what about the symptoms, especially cough, we need to know where she spent her time, was it at home, was it at school, was it at work, and who did she spend the time with and how often was she spending the time with it and how long did she spend the time with? Okay, let's return to our case study of Christine. An initial interview with Christine reveals that she lives with her mother in a room in an apartment with other relatives. The other family members in the apartment consist of Christine's 34-year-old aunt, her 37-year-old uncle, and Christine's 3-year-old niece. Christine is a senior at a local high school where she attends six classes per day. Twice a week after school, she works in the kitchen of a drop-in senior center where she helps to prepare an early supper that has served as center visitors before their bingo game. Her only co-worker in the kitchen is Iris, who is HIV positive. Christine spends most of her free time with her best friend Jane. When asked about other social activities, Christine says her mother is very strict and forbids her to date. However, on the days she is not working at the senior center, she and Jane study for a few hours after school with a fellow student, John, at the school library. Christine was released from the hospital and returned home. From the information uncovered so far, who are Christine's close contacts? Who are her other-than-close contacts? Well, I think we can all agree that her close contacts are the mother, the aunt, the uncle, the 3-year-old niece, Iris, her senior center co-worker, her best friend Jane and her study friend John. But what about the other classmates? Other than Jane and John, were there any others that spent a significant amount of time with Christine? It's often a difficult decision to decide between the close and the other-than-close. And as you can see, we need more information. We should look at the class rosters to determine if Christine had multiple classes with some of these students. But generally, most of the classmates would be considered other-than-close. I'd like to interject here, though. I think it's really important to remember that TB organisms can remain suspended in the air even after the person has left the room. And there has been documented transmission in situations where the person has left the classroom, the actual case, and then the people after them were at risk for becoming infected. Interesting. Would you visit Christine's home, her job, her school? And if so, what would you be looking for? Well, a field visit is essential to observe the environmental characteristics such as room size, crowding, ventilation in order to estimate the risk of TB transmission and identify additional contacts, especially children. So I would begin by visiting the home. It's a less-threatening environment in which to begin your interview. And it also allows you to look for evidence of other contacts who may not be present at the time of your interview. Examples like pictures on the wall, pictures maybe of people who live there but maybe some who don't live there but are close relatives or friends, toys or shoes left by children. Some index cases misunderstand and think that you only want the names of contacts that live in the home. But come prepared when you go for that interview that you can skin test the contacts that are present at the time of your interview and make sure you educate these contacts to TB transmission and also whatever follow-up they need such as arranging their skin test reading appointment and educating them about treatment for LTBI. Okay. What questions will you ask Christine to elicit more information? I think that before we ask her more questions I think you really have to assure her that her confidentiality is going to be maintained. This might make her feel a lot more comfortable. And there's really an excellent interview checklist on the module on page 34 of the contact investigation session. It's really important that we ask open-ended questions. What was she doing? What was the nature of the contact and when was that contact? Was it during her infectious period? How will you follow up with Christine's high school and with the senior center where she works? Well, communication is essential. Having a procedure agreed upon in advance by all parties. The program in TB control, the school, will certainly contribute to the success of the program. Make sure you protect the confidentiality, though, of Christine and include the parents in your education process and also school staff in both education and the testing sessions. You know, in New York City these kinds of situations generate a lot of hysteria and we've developed a kind of SWAT team approach to dealing with these situations. So we have a team of educators and epidemiologists go out to the school. We work very closely with the principal and then we work with the teachers' union and the parent teachers' association with the parents, with the students and we provide education and also are able to set up the whole testing mechanism. Brenda Ashkar will now explore the topics of how to evaluate contacts and how to decide whether or not to expand the contact investigation. Thank you very much. The concentric circle approach is a method of testing contacts in order of their exposure time and risk. The original TB patient, the index case, is in the center of the circle. The circle is divided into three rings to represent three levels of risk, close or high risk, other than close, medium risk, and other than close, low risk. The circle is also divided like a pie into segments representing three types of environment, household residential, work school, and leisure recreation. Evaluation of contacts for both latent TB infection and active TB disease should begin with the highest priority group, the close contacts and those at high risk of developing TB disease in all segments of the concentric circle. The initial evaluation should include a medical history, a mantu-tuberculin skin test, unless there is a history of a documented previous positive. Contacts with a history of BCG vaccination should have a skin test placed, read, and interpreted without regard to BCG status. At the same time as the initial skin test, a chest x-ray is indicated for certain contacts. Those who are symptomatic are HIV positive or other immunosuppressed and those who are under four years of age. Let's talk about the window period. Contacts who are skin tested less than 10 to 12 weeks after their last exposure to a patient with infectious TB may have a false negative reaction because they have not yet been able to react to the tuberculin. It takes two to 12 weeks after TB infection for the body's immune system to react to tuberculin. For this reason, contacts of someone with infectious TB disease who have a negative initial skin test reaction should be retested 10 to 12 weeks after the last contact with the person who has TB disease. The time span between the date of an initial skin test with a negative reaction and the date that is 10 to 12 weeks after exposure is called the window period. After the window period has ended, a repeat skin test should be administered to each contact who had an initial negative reaction. Please refer to the module for more details. The following groups of contacts should be evaluated for treatment of latent TB infection. Contacts with a positive tuberculin skin test and no evidence of TB disease and high-risk contacts such as children under 4, HIV infected and other immunosuppressed with a negative TB skin test under 5 mm, less than 10 to 12 weeks after exposure should have a chest x-ray and start treatment for latent TB infection. Please again refer to the module for window period prophylaxis and more detailed treatment guidelines. It is always important to keep in mind that the ultimate goal of the contact investigation is treatment of contacts with latent TB infection or TB disease. One of the most difficult decisions in a contact investigation is deciding either how far to expand an investigation or when to terminate it. This decision should be made by supervisory, clinical, and management staff. In order to facilitate the decision-making process, contact investigation staff must evaluate the results of the testing that was done for the highest priority group, the close contacts, and those at risk of developing TB disease in the household residential, work-school, and leisure recreation groups for evidence of recent TB transmission. We look for any of the following. First, infection rate among contacts. The identification of contacts who have newly identified positive skin test reactions, 5 mm or more of enduration, can be evidence for expanding a contact investigation. The infection rate among contacts is determined by calculating the percentage of contacts who have a new positive TB skin test. Previously documented positive skin test reactions are not included. For example, if 7 out of 10 contacts have a newly identified positive skin test, the infection rate would be 70%. Generally speaking, recent evidence of TB transmission is probable when the infection rate in a group of contacts is greater than the level of skin test positivity in the local community. This may be a residential area or an ethnic community. For example, if the expected infection rate in a given community is 10 to 20%, and the infection rate among contacts is 70%, the high infection rate among contacts indicates evidence of recent TB transmission. Comparing the infection rate among a group of contacts with the level of skin test positivity in the local community can be a useful tool in determining whether or not to expand the contact investigation. However, this comparison is dependent upon the availability of data. Some health departments may have this data readily available. Others may not. Other factors that should be considered when deciding to expand a contact investigation include infection in young children. Contacts under the age of four with TB infection are at increased risk of progression to TB disease. Since TB infection or disease is uncommon in young children, TB transmission is suspected. Skin test conversions. A conversion is a change in skin test reading from negative to positive. Secondary TB cases. This is when a contact develops TB disease as a result of transmission from the index case. A new contact investigation should be initiated immediately around any secondary case. Supervisory clinical and management staff then evaluates all of the above factors looking for evidence of recent transmission. Using the concentric circle approach, if no evidence of recent transmission among close contacts is noted, testing should not be expanded to the next circle. But if there is evidence of recent transmission within the highest priority circle, the next circle should be tested. This should continue until the level of infection is at or below the level of the community, and there are no other factors indicating recent transmission. Overtesting is not productive and may lead to false fears among those who perceive themselves as contacts. This is especially true in contact investigations which are done in group settings. These group settings can be an industry, school, nursing home, or even an apartment complex. Many group contact investigations have high community concern. Therefore, it is important to determine who are the actual contacts to the case and not be influenced by hysteria or pressure to test persons who may have little or no risk of infection. The staff member in charge of the contact investigation must have a thorough knowledge of the index cases' communicability factors and understand who are the high priority contacts. Education is essential to relieve the fears of those who are actual contacts and merely perceive themselves as contacts because they do not understand the mode of transmission of tuberculosis. Some school contact investigations provide examples of this. Can you imagine the tension when there is a contact investigation occurring in a high school and only certain students are being tested? You, the case manager, must explain to the parents their child who is not a contact is not being tested. With a good education program and a clear understanding of who the contacts are, the school administration is likely to support your decision about who to test. People with little or no exposure to the patient should not be sought out for testing unless there is evidence of transmission among contacts with more exposure. Non-contacts who I have labeled the worried well should be tested if they present for testing. But if they fail to cooperate at any time during the process, they are given little or no priority for follow-up. For low-risk contacts and testing subjects, a cut point of 10 millimeters is generally considered positive. Decision to skin test these people is based on the workload of your program and should be deferred until the highest priority contacts are evaluated. Undertesting of contacts may lead to missed opportunities and cases discovered later that could have been prevented. A review of an industrial investigation revealed that investigation was not expanded after the closest contacts to a smear-positive case were examined. A year later, three new cases linked by DNA to the index case were found. All of these cases could have been prevented if the original investigation had been expanded. Well, now that you've completed your contact investigation, how do you know that it was successful? Program evaluation will give you that information. Evaluation of program performance is important to ensure that program resources are being used effectively. There are seven questions that you'll want to review with your supervisor to assist you in evaluating your program. The first is, were an appropriate number of contacts identified? The situation of a person having no contacts would be very rare. On the other hand, as we've already discussed, over-testing can also occur. Rather than searching for a magic number, it's probably more important to know if the appropriate contacts were identified. And this leads us to the next few questions. Were the highest priority contacts located and tested? Contacts who have shared close physical contact or have spent a lot of time with the index case are considered close contacts and are at high risk of becoming infected. Other individuals, primarily because of having a depressed immune system or a medical condition which is associated with TB, are at high risk of developing TB once infected. Was the contact investigation performed in all settings? Household or residence? Work or school? And leisure or recreational environments? Once again, don't assume that household contacts are the closest contacts. People spend significant amounts of time at work, school and pursuing leisure activities. Was the contact investigation expanded appropriately? The concentric circle approach can guide your decisions about when to expand testing to the highest priority group. Identifying contacts is just part of the process. It is equally important to know if the contacts were evaluated, offered and completed treatment. Therefore, you'd ask the next three questions. Were contacts completely evaluated, including second skin test if needed, and given appropriate therapy if they had TB infection or disease? How many infected contacts completed a regimen of treatment for latent TB infection? Did all identified cases complete an adequate treatment regimen? The answers to these questions will help determine how successful the contact investigation has been and how effectively your program's resources are being used. Well, we have learned that contacts are at high risk of becoming infected with M tuberculosis and if infected at a high risk of developing disease. Effective and successful contact investigations can help prevent additional cases of TB infection and disease, and further reduce transmission of mycobacterium tuberculosis. Thank you, Mrs. Ashkar, for helping us understand when a contact investigation should be expanded. Returning to Christine, we determined the important question to ask during the initial interview and Christine identified her seven closest contacts. Let's return to our story about Christine and the contact investigation being conducted on her case. The health department proceeds to evaluate Christine's closest contacts and to administer tuberculin skin tests. Christine's mother is not tested because she has a previously documented positive reaction. She has no TB symptoms. The rest of Christine's six closest contacts say they have no history of previous tuberculin skin tests and report no TB symptoms. All six contacts were last exposed to Christine two weeks ago when she was symptomatic. Among Christine's six closest contacts, tuberculin skin tests were administered. Two contacts were also given chest x-rays as part of their initial evaluation for TB. Iris, who is HIV positive, and Christine's three-year-old niece. This is because contacts who are immunosuppressed or less than four years of age are at higher risk of progressing to TB disease if infected. Given the possibility of a false negative tuberculin skin test reaction, the initial evaluation in these contacts includes both a tuberculin skin test and a chest x-ray. The results of the evaluation of Christine's close contacts were reported as follows. Christine's niece, nine millimeters normal chest x-ray. Iris, zero millimeters normal chest x-ray. Christine's aunt, 12 millimeters. Christine's uncle, three millimeters. Her best friend Jane, 11 millimeters. And her school friend John, zero millimeters. Christine's aunt, who has a 12-millimeter positive tuberculin skin test reaction, said she was vaccinated with BCG. She insists that her positive tuberculin skin test is the result of her BCG vaccination. Should any of these results be considered positive? We're thinking a key point in a contact investigation is what the cutoff point is for positive. And in this case, it is five millimeters. So anything greater than or equal to five millimeters would be considered positive. And that means that the niece, the aunt, and Jane, the best friend are really considered to have positive reactions. How should the healthcare worker address the aunt's concern that her positive tuberculin skin test is the result of a BCG vaccination? Well, let me try to intact that. BCG vaccine is used to prevent severe forms of tuberculosis in many countries. And it can cause a false positive skin test. There's really no reliable way to determine if the reaction is really from true infection or from the BCG vaccination. And BCG really offers no protection against being infected. And since contacts are at very high risk of being infected, in a contact investigation it's very important that whether a person has had a BCG vaccination or not, that they are evaluated. What follow-up testing or treatment should be given to contacts with positive reactions at this time? All contacts with a positive skin test, five millimeters or greater, or those with TB symptoms should have a chest x-ray. And the reason for the chest x-ray is to rule out TB disease prior to initiating treatment for latent TB infection. And for any contact with an abnormal chest x-ray, certainly would be worked up for TB disease with sputum tests. Okay. Should any follow-up treatment be given to contacts with a negative skin test at this time? Well, your question really brings up the concept of the window period. And this is the period of time after a person is infected where their skin test may still not be positive. So that's anywhere from two to 12 weeks after the skin test is given. And in New York City we treat young children and also people that are HIV positive who are in that window period who have a negative skin test. And we treat them while we're waiting for the results of the second test. Okay. Los Angeles County were fortunate to have the resources to offer window period prophylaxis to all close contacts of infectious cases. Interesting. What additional follow-up should be made with Christine's mother who provided documentation of a previous positive tuberculin test? Well, contacts who have a previously documented tuberculin test, positive tuberculin test do not need another skin test, but should be evaluated for symptoms of TB disease and asked about any history of treatment for TB, either disease or infection. And these folks may need a chest x-ray. And depending on the results of the evaluation, some of these contacts would be candidates for treatment for LTBI. Should any additional contacts be tested? Should the contact investigation be expanded? Well, a contact investigation is expanded if there's evidence of recent transmission. And as we just heard, that's a high infection rate among contacts, infection in a young child, skin test conversion in a contact or a secondary case of TB disease. And in this situation, investigation should be expanded because we have a number of skin test reactors and we have a positive skin test in a young child. To what segments of the circle, school, leisure, et cetera, should the investigation now be expanded? Well, all segments really should be expanded. Remember that the contacts can come from any one of these areas that you just mentioned. And a good history will really help to delineate who in these segments are really at risk. Okay, thank you. Let's see how the evaluation of Christine's contact proceeds. Since there was evidence of transmission of TB among Christine's close contacts, the contact investigation was expanded to include Christine's six high school classes. Tuberculin skin tests were offered to all teachers and students in these six classes. In addition, school contacts were asked if they had signs and symptoms of TB. The following results were reported. Of 129 student contacts, 110 were negative, with skin tests less than 5 mm. 11 were positive, with skin tests greater than or equal to 5 mm, and with negative chest x-rays. 8 were documented with previous positive reactions. Of the six teachers, all six were negative, with skin tests less than 5 mm. What follow-up testing or treatment should be given to contacts with negative skin tests now? Well, since it takes 2 to 12 weeks after TB infection for the body to react to Tuberculin, contacts who are skin tested less than 10 to 12 weeks after their last exposure may have a false negative reaction. So the time span between the date of an initial skin test with a negative reaction and a date that's 10 to 12 weeks after exposure is called the window period. After the window period has ended, a repeat skin test should be administered to each contact who had an initial negative reaction. And the high-risk contacts with negative skin tests, less than 5 mm of induration, and those, as we talked about, are the immunocompromised and the children under 4, should be evaluated for treatment of LTBI after the initial negative skin test. And this is called window period prophylaxis. All of Christine's contacts receive their initial test approximately 2 to 3 weeks after their last exposure. So those with a negative skin test need a second skin test after this window period is over. Let me repeat the numbers. You can call in your questions on our toll-free number 888-565-8673. For those of you outside the U.S. 415-861-8543. And again, our fax number 415-626-3110. Let's go back to our story of Christine. The health care worker suggests that she and Christine conduct their follow-up interview without her mother present. Christine agreed to meet the health care worker at the senior center. During the conversation, Christine reveals that she's been secretly involved for several months with a 25-year-old man named Victor who lives by himself in an apartment in her building. She felt bad about not naming him earlier but assumed it was okay because he told her he felt fine. What have we learned from this second interview? Well, I think this situation really points out the need to do a reevaluation of the index case. And here it's confidentially, confidentiality must be stressed because it may make the person feel more comfortable about revealing more information. And also it's an opportunity for us to do a little bit more of education and understand the importance of getting context. And here's an opportunity for us to do that. Yeah, we generally have tended to do a second interview about one month after the first one. Things come up. Let's see how the investigation continues to unfold. Victor is contacted by the health department and makes an appointment for evaluation. He declines a home visit to protect Christine's privacy. He has no history of a positive tuberculin skin test reaction. His skin test is 13 millimeters. He is evaluated for symptoms and has none and is given a chest x-ray, which is normal. He has started on LTBI treatment. As you recall, the initial evaluation of Christine's contacts took place two weeks after their last exposure tour. This two-week time span falls within the window period of 10 to 12 weeks that it can take for the body to recognize TB infection. Therefore, all of Christine's contacts who had negative reactions to the first tuberculin skin test were retested 12 weeks after their last exposure to Christine while she was symptomatic. The results of the second tuberculin skin test were as follows. Still negative, co-worker iris, 0 millimeters with normal chest x-ray, Christine's uncle, 3 millimeters, 100 students and 5 teachers, less than 5 millimeters. The new positives are school friend John, 14 millimeters, 10 students greater than or equal to 5 millimeters, one teacher, 11 millimeters. Once again, to review the results, the previously documented positives are Christine's mother and 8 students. The contacts who tested negative are Christine's uncle, 3 millimeters, iris, 0 millimeters with the normal chest x-ray and 100 students and 5 teachers all less than 5 millimeters. The contacts who tested positive are Christine's niece, 9 millimeters with the normal chest x-ray, Christine's aunt, 12 millimeters, Jane, 11 millimeters, Victor, the secret boyfriend, 13 millimeters, John, 14 millimeters, 11 students at an initial tuberculin skin test 2 weeks after their last exposure, greater than or equal to 5 millimeters, 10 additional students and 1 teacher when retested again after the window period at 12 weeks, greater than or equal to 5 millimeters. Well, should the contact investigation be expanded? Yes, there is additional evidence of recent transmission. There's a new positive reaction with Christine's study friend John, also 10 students and 1 teacher converted from a negative skin test at the initial test to a positive at the second test after the window period. And as we know, any contact who has a skin test reaction of 5 millimeters or more on either the initial test or the follow-up 10 to 12 weeks after exposure should be evaluated for treatment of LTBI. Well, where do we go now? To what segments of that circle work, leisure, and so on? Should the investigation be expanded? I think we have to ask ourselves, we've been quite thorough in our investigation, but for example, are there any other people that she may have spent time with in the high school that she didn't originally identify? And also, she has to travel from her school to work, et cetera, and how did she get to those places? Maybe she's in a car. She shares a car with somebody and that might be an additional place to look. Okay. Well, let's repeat those phone numbers. Our toll-free line is 888-565-8673 outside the U.S. 415-861-8543 fax numbers 415-626-3110 We'll conclude our case study of Christine with one final development. During the contact investigation, the director of the senior center where Christine works hears from Iris about Christine's TB. The director calls the health department and demands to know why all the seniors who visit the center for twice weekly dinner and bingo aren't being tested. What response should be given to the director of the senior center? Well, as you'll recall, Christine doesn't have contact with the seniors at the center. She only works in the kitchen to prepare a meal which is served to the seniors after she leaves and the seniors have no access to this kitchen area. And so the people in the senior center other than her co-worker Iris are simply not contacts. And so therefore we don't plan to do a contact investigation at the senior center. But frequently you receive requests to expand investigations in institutional settings and these are more driven by fear, lack of understanding of TB rather than by hard evidence of transmission of TB. In this situation it's essential to have health department staff go to the center and provide TB education to the staff, the visitors to alleviate their fears. A decision to skin test these people is based on the workload of your program and should be decided by supervisory clinical management staff. But a good rule to follow is to defer any contact follow-up there until the highest priority contacts are evaluated. Thank you. Mrs. Ashkar and Dr. Fujawara now the faculty would like to respond to your questions. Please call the toll free number that appears on your screen. 888-565-8673 for those outside the US 415-8618543 and again our fax number 415-626-3110 Please use a regular handset, not a speakerphone and speak as far away from your television monitor as possible. You can help us accommodate as many collars as possible by limiting yourself to one question. Our first call is Evelyn from San Diego. Evelyn, go ahead. Hi, Gisela and Brenda. We wanted to get I can hear you getting some feedback. Let me move back. We wanted to ask with the example of the law student and the visitors that were over for Christmas dinner using the concentric circle how would you decide whether or not to test those contacts that had just an hour or two exposure? Who wants to make a go? Dr. Fujiwara? Evelyn, I think this is from the presentation that I made and it really they spent only a little bit of time with the source case in that instance and I think it's important that you look at other people that he had more contact with and see if there's any kind of transmission there and then you can make the decision to see if you need to really go on and do the people that spent that much shorter amount of time with him. Our second question will be Bill from Tallahassee, Florida and his question is up to what age should a source case investigation be? That's a very interesting dilemma and a lot of it has to do with what kind of results you get in many jurisdictions including Los Angeles County we will do source case investigation on child reactors or as we call them converters under the age of four but for children who are TV cases we will do an investigation really at any age and you have to look at what your outcomes are and where you get the most for your investigation time. It's been also experienced the same in New York City. The younger the child the more a chance you're going to have of actually finding the source case. Now we have a faxed question from Anne in Santa Maria, California her question is during a source case investigation should other children finally be tested? I can go ahead and start with that. Yes, and the reason is is that the other children in the home have probably been exposed to the same source case as this child who is either a case or a reactor and it would also probably gives more impetus to your investigation if there are more reactors in the home also. Our next question is from Sandy in Harrisburg. Go ahead, Sandy. Yes, this is in regards to a homeless person who is now in jail, is uncooperative cannot he will not notify or we can't contact his we can't identify his contact because he won't cooperate with us. He's drank in various bars he's active with TB, he has symptoms he has numerous smears and he is culture positive. How do we identify his contacts while maintaining his confidentiality? Dr. Fujwara. Sandy, that's a really tough situation as you know and I think it's important that you've tried you've tried to talk with the person but sometimes we don't know what it is that motivates this person so sometimes you have to figure that out and the other thing that's useful is to have other people try to do some some interviewing too to see if that is also possible but there are some situations where I hate to say this but you may not be able to find the contacts because they are so difficult such as the one that you described here. You know, I think one of the things you mentioned Sandy is the confidentiality and some states and California and one where if it's to protect the health of the public you can breach confidentiality and so in this case it may be the need to show this person's picture around the Skid Row area and see if he's recognized because often patients go by a kind of a nickname rather than their given name. And you also gave a clue that you know that he goes to a certain bar so it would be perfectly appropriate to go to that with the regulars. Our next question is from Sharon from Franklin, Pennsylvania. Go ahead Sharon. Thank you. Would you please address the booster phenomena when doing a contact investigation? Dr. Fujwara? Yes, the booster phenomenon is a situation where the person is actually infected with the organism but it doesn't show up. The germs are kind of sleeping and so when you do right after that it means that the person was actually infected if the second test is positive that the person is actually already infected. In terms of what we have to do in the context of a contact investigation it's been our practice to actually kind of we don't do a second booster like one or two weeks afterwards. We do wait for that 12 week period to be over and if it is positive on that second test we do assume because it isn't the context of a contact investigation that that person does indeed have a positive skin test. And I would agree a two-step generally isn't indicated in a contact investigation although I realize you could say in an elderly population or a nursing home but I think when you know someone's been exposed if the second skin test after the window period is positive then you have to assume that this is an infection and not just a boost. Our next question is from Carolyn and Arnold Maryland. Carolyn? Yes, thank you. In Christine's contact evaluation would sputum evaluation be appropriate in the contact who was HIV positive with a negative PPD and a negative chest X-ray since some HIV positive patients with TB have negative chest X-rays? I'm going to ask Dr. Fujawara to address that. Carolyn that that is does come up sometimes with a person she's HIV positive she does have a negative X-ray she has no symptoms. I think that in this situation given the fact that she has no symptoms that I would be probably less likely to get a sputum evaluation however if her X-ray had been negative and she had a symptoms of tuberculosis then probably I would go ahead and do sputums. Thank you. Our next question will be a fax question from Donna in Raleigh, North Carolina hope the weather is good. Do you recommend doing a contact investigation on smear positive culture negative pulmonary TB disease cases? You know that's the way I see it if the person was smear positive then you would have been initiating that contact investigation for three days. Interview time should be within three working days and I think even though our new technology is wonderful for laboratories we wouldn't have gotten the culture back yet. Now if it was a delayed contact investigation and you did have the culture result I think that's clinicians determination of whether or not this is a case if all clinical correlation points to TB despite the negative culture then most certainly continue your contact investigation if the physician feels otherwise then you would stop it. Thanks. All right, Patricia from Madison, Wisconsin go ahead. My question is a two part question the first part should individuals who are considered to be low risk test positive for TB infection but who are without symptoms and show a negative chest x-ray always receive oral TB therapy and has there been any follow-up such as longitudinal longitudinal studies to determine treatment results in such individuals i.e. did they ever have TB infection in their lifetime? Dr. Fujiwara? Let me address that, Patricia so the issue is as a person at low risk but already has a positive skin test as no symptoms and negative chest x-ray should that person get treatment for well if it was in the context of a contact investigation probably I would lean towards giving the person treatment for latent TB infection but if this is just a person who came in for whatever reason and got tested this is really considered a low risk and as we know that the CDC's new recommendations are a decision to to test somebody is a decision to treat however in many situations you get the results after the person's been tested and that's where the decision comes in so it doesn't in a general situation you don't necessarily have to think about treating all of those people Our next question is going to be a faxed question from Maria in Detroit, Michigan during a contact investigation if we have somebody who says they had a positive skin test in the past how should we evaluate them? We get that question very often we say you need to have be able to document the results of a previous positive and that doesn't mean just hearsay come up with some health provider in writing that you have a previous positive and so if you cannot document a previous positive then we would give you another skin test but I don't think it's just black and white and what I instruct the nurses is to please ask open-ended questions ask if you know tell me what your skin test result looked like was there any follow-up after and therefore you can make your decision from there Our next question is going to be from Amelia from Yakima, Washington go ahead Amelia Yes, thank you in a contact investigation should contacts to an active case that have tested negative start on treatment until the time for their next tuberculin skin test which would be after the window period and if negative then stop treatment In our presentation we stated that negative contacts would be offered treatment for LTBI if they were in a high-risk group immunocompromised or children under the age of four I also mentioned that in our jurisdiction in Los Angeles County we do have the resources so we would offer window period prophylaxis to the negative PPD close contacts of infectious cases but that's not the standard throughout the country I think there's a second question in there after the second one is done and it's after the two 12-week period and if it's negative then you can assume that the person is really not infected and stop treatment at that time correct Our next question is going to be from a faxed question from Andrea in Alexandria, Louisiana at our health department we normally have the opportunity to administer one skin test on each of the contacts it seems like doing a second skin test will take a lot of resources why is it important? Dr. Fujiwara? well Andrea the issue here is a discussion and if you don't have the resources are not available then you can do only one however if you're only going to do one it should be done after that window period is over there's no use doing it in the middle because you'll never know if it's negative during that window period you'll never know if that person truly was infected or not however you should realize that you do run the risk of not identifying some early infections and also people that who may be or may not necessarily turn out to be cases Our next question is going to be from Joan in Bridgeton, New Jersey go ahead Joan Hi, thank you for taking my question in a contact investigation is a two-week-old infant held for about five minutes by a TB case should that baby be considered a close contact? well is the case coughing etc etc etc that's true a two-week-old infant is such a susceptible organism that I probably would consider that a close contact although it's so difficult exactly what Dr. Schechter said earlier was this case coughing on that infant how long had the case been on medication I mean you have to look at all of the factors but also I would err on the side of being more conservative with the child of that age the clue that I think we can use also is that what was going on with the other close contacts for example if you did an investigation in the other close contacts there's a lot of transmission there then maybe that would skew you toward evaluating the child as being also much at risk if there wasn't much transmission in that close circle other people in the close circle then maybe you could decrease your level of anxiety there but the question, not a name given but from Harlem, New York how do you follow up on close contacts who refuse skin testing can I give that to Dr. Fujiwara of New York well I can talk to you from the point of view what we do in New York is that we're quite aggressive and and again the techniques to use there are that if you're not successful something to talk to with your supervisor maybe he or she has some hints that can be offered and also to use another person to do to do the interview again and try to get that person to adhere in New York City we do have a detention policy for actual cases but this does not apply to people that we're just trying to skin test we just want to make that clear alright the next question is from Judy in Honolulu, Hawaii go ahead Judy yes my question is are patients that are HIV positive or immunosuppressed is there a need to determine energy in those patients Mrs. Ashkar we don't recommend energy testing but if you have a negative skin test on the initial and a negative skin test on the follow up there are some jurisdictions that would look to continue the treatment for latent TB infection in that type of patient because of their immunosuppression and the difficulty in telling whether or not it's a true negative or energy and we've seen those situations where a person is in fact not even allergic but reacts to another antigen still has TB but has a negative skin test and I think the energy testing is probably not worthwhile but you might treat that person anyway alright Sylvia from Los Angeles, California go ahead Sylvia yes in a contact of instigation for a culture positive for MTP patient you're doing a contact follow up and we identify high risk contacts to have a PPT positive at 5 millimeters therefore they would be considered positive would you retest these people over again after the window period between 10-12 weeks later because most physicians in the private sector usually won't consider these positive unless it's over 10 millimeters well I guess I have my work cut out for me in Los Angeles to try to educate these physicians but we can show them in writing that 5 millimeters or greater is a positive skin test for a high risk contact and so therefore they would not need to have a follow up skin test then they would be candidates x-rayed and be candidates for treatment for LTBI thanks alright our next question is going to be a fax from Steven also from Los Angeles during interactions with patients I commonly discuss sharing airspace with others instead of the word contact I think this helps in the elicitation of contacts do you have any thoughts Steven the issue of this sharing air contact which you're talking about is vocabulary and what makes sense to the patients certainly what we say a lot in the TV world is we talk about contact investigations all the time and contact does mean different things to different people so you're trying to be more specific with the sharing of the airspace if that works then I think it's something that can be used and I agree you always have to talk to the level of the patient if you're going to use jargon they're not going to understand what you're talking about and this is exactly how we fail in contact investigation and so I think your idea is an excellent one next we'll do a fax from Amy in Manitowoc, Wisconsin I'm sorry if I mispronounced that the question is how do you determine the level of skin test positivity in the local community Dr. Fujawara do you want to take first try that's a very that's a difficult question because that implies that there are going to be routine or systematic ways of doing skin test surveys within the community and in most I'll talk about New York City for example we do not have those kind of systematic data there may be in other parts of the country where that is done but it's just hard to get background what we end up doing is doing specialized surveys for example healthcare workers or people in nursing homes we can kind of put data together in an aggregate form you have to really look at the population that you're dealing with and it becomes very very specialized it's hard to get that background we don't though we talk about it a lot I agree and talking about the infection level in the community we're not necessarily talking about a town we're talking about facets of the community and your demographics and so in a community as diverse as Los Angeles we try to get some estimate of the infection rate in like the Latino population the Asian population we can get it in our kindergarten students and so you look at various measures of level of infection depending on who you need to have this number on but again it becomes an estimate very frequently our next question is going to be from Jim Burley of Westminster California go ahead hi this is Jim Burley public health nurse from Orange County Public Health and I have a question we have a student a dog student with positive PPD and all kind of symptoms of TB and have chest x-ray non-cavitary x-ray and the other student with the positive PPD all kind of symptoms with a cavitary x-ray so they both you know attend the school so how far do we go back to identify the context all right did you want to Kimberley are you meaning in a period of time how far do you go back it's not still on but basically you use the concentric circle and it sounds like from what you're telling us the second student is a secondary case from the first student and so therefore you would expand the circle and I'm assuming you started with doing all of the classes that Kimberley was in and from there you might have to go further and what classes as Dr. Fujiwara said earlier what classes followed the classes that each of these students were in to expand the circle until your infection rate then basically meets that of the community that you're in I think another thing to remember is that you really have to really delineate when those symptoms started because that's really going to help you to know how far back that you have to really go it might very well be four months, six months but it's true it depends on the both of the cases symptoms, duration of symptoms all right our next question is from a faxed one Marilyn from Carlisle, Pennsylvania how do you differentiate between a BCG reaction and a TB infection Dr. Fujiwara well a BCG a BCG reaction BCG as we know can cause a skin test to become positive, TB infection does the same thing it's extremely difficult it's just impossible just from looking at the reaction you're not going to be able to tell if it was truly from BCG or from TB infection however we have some rules of thumb in that the larger the reaction is and usually because the BCG has been given in childhood and it's usually a lot of times you're looking at an adult the larger the reaction is the less likely it is is going to be from the BCG and we actually follow the rule that if the BCG was given more than one year ago and that the skin test is above the cut point whether it's contact cut point or screening then we consider a TB infection and not a BCG reaction Mike from Anchorage, Alaska how can confidentiality be preserved when contacts in the school worker home are well aware of the fact that the index patient was or is ill as long as you're not the one confidentiality and if you're asked you can't just agree oh yes of course it was Mike the patient but one of the things we've done which has been somewhat interesting is that if we're calling the class in for skin testing if the school nurse is doing it or it's being done on the premises we'll also call in the index case and therefore at least to preserve somewhat that she or he is being treated the same way but sometimes you can't always preserve the confidentiality that concludes the time we have for our question and answer period we're sorry if we couldn't get to your call or fax following today's broadcast our faculty will be available for another half hour or so to take some additional telephone questions from you use the toll free telephone number on your screen at the end of this course we will assemble a list of the most commonly asked questions and our responses to them and post them on our website before we close with some final housekeeping details let's hear TB control staff from San Francisco review the steps involved in a contact investigation the nine steps involved in a complete contact investigation are number one, review the medical record number two, interview the patient number three, conduct a field investigation number four, assess the risk or transmission of the TB bacteria number five decide which contacts are the most important number six, evaluate contacts relating to TB infection and active TB disease number seven, treat and follow up contacts number eight, decide whether or not to expand testing using the concentric circle approach number nine, evaluate your contact investigation next week on Thursday, February 3 at this same time we'll be covering material contained in the next two self-study modules in your series module number seven confidentiality in TB control and module number eight TB surveillance and case management in hospitals and institutions please remember to read both of these modules in advance of the broadcast if you did not receive a set of the self-study modules for reviewing this course they can be ordered directly from the CDC call 4046398135 we thank you for joining us in this first session of TB Frontline thank you to Dr. Fujawara and Mrs. Ashkar for helping us to navigate our way through the important and complex topic of contact investigation we'll see you next Thursday, February 3 at this same time for our second session of the course, have a great day