 Does HIV cause AIDS? Here are some facts. This is an immunodeficiency virus. Family retroviridase, subfamily ortho retroviridase, genus lentivirus. It infects T cells, CD4 positive and CD8 positive T cells. B lymphocytes and macrophages. The prevalence is 2.5% in the U.S., 11% worldwide. The highest prevalence is in Africa. It's transmitted by blood blood or blood saliva contact. It's transmitted from female to offspring via in-utero transmission. It causes immuno-compromise via depletion of CD4 positive T cells. Symptoms include susceptibility to opportunistic infections. Testing by indirect antibody testing for seroconversion by ELISA. False positives are known for newborns who drink mother's milk, abortive infections or exposures, vaccinations or cross-reactivity. False negatives are often caused by seroreversion where antibody-producing cells are lost during subclinical phase. There are no fully effective vaccines available in spite of years of research. There are three stages to the disease. We have the acute stage, which happens immediately following transmission, brief flu-like symptoms, depression, swollen lymph nodes, followed by subclinical stage, where we have no symptoms, but we may not even show signs of virus, which leads to the chronic phase where we have opportunistic infections, inflammation of eyes, skin, gums, lungs, and there are some known non-progressors and some natural immunity. Okay, that was a mouthful. Which virus and which disease am I talking about? If you guessed HIV-AIDS, you are wrong. Here's the face of the virus I was talking about. I've been talking about FIV, feline immunodeficiency virus. Let me review those facts again. It's in the same class family genus. In fact, the genomes are extremely similar, almost all the same genes, although HIV has a better trans-activator protein. FIV also infects CD4 positive T cells of cats, and the resulting immunocompromise is the same. The method of transmission is similar, but what's interesting is that FIV is more often transmitted by bites between males than via normal heterosex between two cats. Cats, like most animals, don't have the same interest in sex that people do on a year-round basis. These are the transmission rates for HIV according to Dr. Wikipedia. Heterosexual sex results in 5 to 10 infections out of 10,000 exposures. Worldwide HIV rates are a little less than 1%, according to my own estimate of the numbers I have access to. Worldwide FIV infection rates are 10%, but in the U.S. with proper testing and management, those rates are 2%. Prevention of FIV is pretty simple. Keep your cat indoors at all times. FIV prevalence rates in African lions are as high as 95%. The lions appear to have developed tolerance to the virus, but domestic cats have not. It would be an interesting topic to research to see what is known about FIV resistance in wild African lions, but not relevant for this video. FIV is transmitted from mother to kitten in utero. That's to be expected. Kittens born to infected mother cats will derive antibodies in mother's milk. There is a vaccine available, but only protects from a few clades and the protection is not complete. This is actually the same challenge we face with HIV vaccines, and incorrect or incomplete vaccination can actually accelerate virus transmission because it makes it easier for the virus to enter immune cells, its favorite host. There are three stages to FIV, just like HIV AIDS. All intiviruses are slow viruses, meaning they spend part of their life cycle lying dormant in the host genome, resulting in a long subclinical phase. It's not until they are triggered by some stress on the host cell to reemerge and produce frankviremia detectable levels of actual virus particles. Testing for virus particles during the subclinical stage would always be a negative. That's one reason why tests for FIV and HIV focus on seroconversion, or antibodies against viral targets. This can lead to false positives. That's antibody, but no virus. Why? Well, sometimes the immune system wins the fight. The host is exposed to virus, but not infected. The antibodies and the cells that produce them stick around. Another possibility, cross-reactivity. Sometimes antibodies against something else will also react to the virus. That's why ELISA tests for a single target are not good evidence. With each additional test for a different antigen, the chances of cross-reactivity explaining the results drop. I will explain in a different video why there is no reference standard for HIV antibodies. What about the other viruses related to HIV? Well, there's Simeon immunodeficiency virus, and it's pretty well tolerated, like Lyons and FIV. But if you take the virus from an African monkey and infect an Asian monkey and vice versa, they both develop Simeon-acquired immunodeficiency syndrome, just like taking a Lyon virus and infecting a house cat. In the same group as HIV and SIV, the primate lentiviruses are three other viruses I'd like to mention. Equine infectious anemia virus, and this is the one I was most interested in, it's also known as swamp fever. It follows the same course as HIV and FIV, but it results in chronic fever and fatigue. It infects a slightly different type of cell, so monocytes and macrophages, but not CD4 positive telomphocytes. And it does have one extra gene that enables it to do so that HIV lacks. It's also transmitted by blood blood in utero, but also by biting insects. Caprine arthritis encephalitis virus, or CAEV, is probably, well that's goats by the way, is probably closely related to EIAV. It infects the same types of cells and it has that extra gene. It's extremely prevalent, 35 to 81% of dairy goats tested positive for it, although only 35% will show clinical signs, which includes autoimmune arthritis and wasting. In young kids, here we're talking baby goats, it results in failures to thrive and neurological problems. It appears to be transmitted in utero or by blood blood or blood saliva contact. Bovine immunodeficiency virus, well you get the idea. So in conclusion, if you want to believe that HIV doesn't cause AIDS, fine, but that would make it a very unusual member of the group of viruses it belongs to. If you want to believe that HIV is a vast conspiracy of the world's scientists, physicians and healthcare workers, fine, but are the veterinarians in on it too? But if you, like Dr. Duesburg, want to say that HIV is as the cause of AIDS is unlike any other virus disease relationship, you are just wrong.