Q: Could you please tell me how long does the HIV virus survive once it is exposed to air? I have the fear that man/woman are more vulnerable to the disease. For instance, if the skin gets cut in a hair dressing saloon, though the barber uses a new blade, but he wipes the cut with a towel which has been used by many others - could it turn out to be fatal? Please let me know whether the virus enters the body from the cuts and the maximum time the virus survives once it is exposed to air.

A:The chance of getting an infection from a barber shop is very, very low. I once calculated the odds and there was a very, very small chance of infection from a barber shop. Of course it makes since to ensure that only a new razor blade is used for each person. In the context of your specific queries, the virus lives a very short while outside the body. As a general rough and ready guide you can assume, especially for a small amount of blood, that the virus is only viable for the time that the blood remains liquid. After drying out, the virus soon dies -- the time is not in days but in minutes. Yes, a person can get infected from a cut or wound but only if viable virus enters his blood stream through the break in the skin. Please always remember that while it is best to take all precautions, HIV is not very infectious and does not get transmitted by casual contact. Even when a non-infected man has unprotected intercourse with an infected woman, the chance of infection is 1% or less. This does not mean that you can afford to take any chances -- the low infectivity will be no consolation to a person who does get infected. Casual daily life exposure to infected persons can be assumed to be safe.