Q: I am a 24 year old man and i have a few doubts about AIDS. Almost about one and half years ago at the city bus station I picked up a tooth pick fallen on the ground to pick out the guava seed in my teeth. I had not realised that it was a toothpick initially and after picking out the seed, I realised that it was a toothpick. But I have bleeding gums and while using the toothpick blood flowed out indeed. I know its a stupid and unhygienic thing to do but then it was too late. Immediately I had fears of contracting HIV virus through this. Can HIV be contracted through saliva? If yes, how much amount of saliva is required(in ml) to contract HIV virus? For how long does the HIV virus survive after it is exposed to the atmosphere (the toothpick was not a new one and it had a lot of dust on it, so I presume that it would have been at least a day old)? How much minimum amount of blood is required to transmit HIV virus? After how many months of the exposure should we go for the HIV tests? I know that my story seems fabricated, but believe me this is what actually happened. Also I have not had any sexual intercourse with anybody till now and I have been using disposable syringes till now. I would be very grateful to you if you could help me out in this matter.

A:First, I must say that though what you did was not very hygienic, I do not think you will have any serious risk of HIV infection. Forget about it and if you still feel worried, get a HIV test done. If even one test is negative you can be sure you are not infected. If you get a positive result, do not get worried until you get another test. If any test is negative, stop worrying. As to your other question the position of saliva is not very definite but just as you have bleeding gums, other people can also have some blood in their mouth so don't take chances.