HIV survives for only a very short period of time ouside of a host. If its just sitting there in the sand clotting, its not gonna last long. not to mention even if you did get stuck with a needle you risk of getting HIV is only like 1-3% and can be reduced to almost negligible if you take prophylactic therapy. I dont know the stats on hepatitis, but all of our soldiers have been vaccinated against Hep B. Hep C is what you really worry about in the hospitals, as a stick has like a 25% transmission rate. Not a fun disease to have, many folks will go on to develop liver failure and a small group of people will even develop hepatocellular carcinoma. At any rate I dont believe the survival time outside the body is very long for hep C either, but I dont remember the numbers on this one.