what are the chances of infacting HIV or AIDS ,if this kind of situation ???? yesterday i travelled in the mumbai local train frm church to borivalli that was the last train of the night,i was in the first class compartment,i sat next to the window seat but there was a pin(tachni) some one had fixed it to edge of the window & it was poke to me,and very minute amt of blood came out from my right hand muscle side,...will i get infected with hiv or aids?? & wat is the life span of the HIV virus in the air???