I read somewhere that cats carry disease(s) that may be a
hazard to people who are HIV+. I'm wondering at what point
the risk develops. Would it be a risk to someone who may
have experienced HIV related acute viral syndrome whose
lymph nodes remained painful for several weeks? Or from the
time one tests positive? Or much later in the progression of
the disease when the immune system is further compromised?
Thank you for your question. When it comes to cats and persons with HIV infection, the main risk is acquiring an infection called Toxoplasmosis (often nicknamed "Toxo"). This is an opportunistic parasitic infection that causes illness in persons with severely damaged immune systems. This infection does not cause illness in persons with fully functioning immune systems. If a person has HIV and Toxoplasmosis, they are considered to have full-blown AIDS. It is not the cat itself that transmits Toxoplasmosis. Rather, it is exposure to the feces of the cat that poses a risk. Therefore, anybody with a damaged immune system should not be changing cat litter boxes. Toxoplasmosis can also cause birth defects to the unborn child. Therefore, pregnant women should also not be changing cat litter boxes (regardless of whether they have HIV or not). In both of these situations, it is best if another member of the household changes the litter box. If a person with a damaged immune system (or a pregnant woman) must change the cats litter box, they should wear gloves and a mask. They should also avoid as much as possible producing dust while changing the litter box (some brands of litter produce less dust than others). If a cat does not use a litter box (it goes outside), then the cat would not pose a risk of infection (since you would not be exposed to the feces). If a member of a household is pregnant or immunosupressed, a veterinarian can test the cat to see if it has Toxoplasmosis. I cannot emphasize more, that it is not exposure to the cat itself that poses a risk....just exposure to the cats feces, that poses a risk.
In addition, persons with damaged immune systems are more susceptible to bacillary angiomatosis, an illness very similar to "Cat Scratch Disease". This bacterial infection can be transmitted through a scratch or bite from a cat (often a young cat or kitten). Therefore, if a person with a damaged immune system gets scratched or bitten by a cat, and subsequently develops malaise, swollen lymph glands, or fever, they should see their physician as soon as possible.
If you have any further questions, please feel free to call the Centers for Disease Control at 1.800.232.4636 (Nationwide).