 Rift valley fever, occurrence patterns, signs and symptoms. What is Rift valley fever? Rift valley fever is a viral disease that affects sheep, goats, camels and cattle resulting in abortions and deaths in young animals. It also affects humans leading to transient fever in a majority of cases but in a few cases the infection can escalate to a severe disease characterized by extensive bleeding and death. Which people are more likely to get the disease? Herders sleeping with their animals in sheds, bombers and crows People taking care of sick animals, particularly assisting aborting animals and those giving birth Animal health workers treating sick animals and performing post-mortem inspections Arbatore workers and people involved in slaughtering sick animals People who may get in contact with excretions from sick or dead animals affected by the disease Those who may handle uncooked meat or drink blood and raw milk of animals affected by the disease How do animals get the disease? Rift valley fever is caused by a virus transmitted by mosquitoes Some mosquito species such as Aedes and Culex have a higher capacity to transmit the virus than others How do mosquitoes come about? Following excessive and persistent heavy rainfall, flat areas get flooded resulting in small lakes that are referred to as Dumbos Dumbos are used by multiple species of mosquitoes for breeding Mosquitoes that develop bite animals that come to these Dumbos to take water or those from the neighboring livestock camps, bombers, crows and grazing areas where these mosquitoes can reach as they swarm to seek blood meals How does Rift valley fever virus get transmitted in animals and people? Mosquitoes can transmit Rift valley fever to susceptible wildlife, domestic animals and humans as they feed An outbreak occurs when many animals have been infected and can show clinical signs This requires large populations of mosquitoes and biting flies to enhance mosquito host contacts enhance the chances of virus transmission Livestock vaccination campaigns in infected areas can also transmit the virus through the use of contaminated vaccination needles Vaccination during outbreaks is therefore discouraged People can also get the disease by coming into contact with blood, body fluids and other tissues of an infected animal particularly aborted fetus tissues and fluids In rare cases, people can get infected by consuming raw milk and meat from affected animals How often does disease occur? Outbreaks occur after long intervals of 5 to 15 years A few cases may occur during the normal rains but these often go undetected Which areas has the disease previously occurred in East Africa? In Kenya, areas that are prone to Rift valley fever outbreaks include Mandera, Marsobit, Wajir and Garisa counties in north and north-eastern parts of the country Tanareva, Kilifi and Kuala counties in the coast Buranga and Thika in central and Baringo, Naivasha and Kajiado in the Rift valley In Tanzania, the disease has previously occurred in many areas including Arusha, Kilimanjaro and Tanga in the north Dodoma, Singida and Magnoni in central and a few other areas in Lake Victoria region In Uganda, RVF outbreaks recently occurred in Kabale, Arua, Mubende and Kiboga districts How many animals in the herd will be affected? About 20 to 90% of sheep, goats, cattle and camels in entire herds may be affected by the disease during outbreaks What are the effects of infection in livestock? Young animals are extremely susceptible with 70 to 100% of lambs and camel folds succumbing to the disease Sheep are highly susceptible and about 20 to 70% of them die when infected Cattle and humans are moderately susceptible and less than 10% die when affected Donkeys are resistant while birds are not susceptible In case of any of the above signs and symptoms, please report to your local veterinarian, medical practitioner or Rift valley fever disease multi-sectoral coordination units across East Africa This video was developed by the International Livestock Research Institute with support from USAID's Office of US Foreign Disaster Assistance