Scientists agree that a fragile virus such as HIV does not survive well in the environment but the jury is still out on exactly how long it can survive outside of a host.
studies have shown that drying of HIV-infected human blood or other body fluids reduces the theoretical risk of environmental transmission by 90 to 99 percent within several hours.
This is according to Avert an international aids charity.http://www.avert.org/faq1.htm#q22
Hours? What happened to seconds and minutes?
variant Creutzfeldt-Jakob disease or mad cow has proven to be resistant to sterilization and might be spread via the reuse of surgical instruments http://www.sciencedaily.com
Read more, ask more, and learn more. Do as much as you can to separate the wheat from the chaff. Then make an educated choice, decision and hopefully not a mistake.