HIV stands for human immunodeficiency virus. It is the virus that can lead to acquired immunodeficiency syndrome or AIDS if not treated. The CDC provides a description and recommendations for prevention on their website.
Cholera is caused by the bacteria Vibrio cholerae. For more information, check out the CDC's website.
The Latin name for bacteria associated with the Black Death is bacterium Yersinia pestis. The CDC provides a description of what The Plague is on their website.