Answer: Anthrax, Typhus, and HIV
Anthrax can be contracted through the digestive system, abrasions on the skin or inhaled through the lungs. It is often fatal. Typhus is caused by Rickettsia prowazekii, which is carried by body lice. When the lice feed on a human, they may simultaneously defecate. When the person scratches the bite, the feces (which carries the bacteria) are scratched into the wound. Body lice are common in areas where people live in overcrowded, dirty conditions, with few opportunities to wash themselves or their clothing. Because of this fact, this form of typhus occurs simultaneously in large numbers of individuals living within the same {community;} that is, in epidemics. This type of typhus occurs when cold weather, poverty, war, and other disasters result in close living conditions which encourage the maintenance of a population of lice living among humans. Epidemic typhus is now found in the mountainous regions of Africa, South America, and Asia. Recent research indicates that HIV replicates prodigiously and destroys many cells of the immune system each day. But this growth is met, usually for many years, by a vigorous defensive response that blocks the virus from multiplying out of control. Commonly, however, the balance of power eventually shifts so that HIV gains the upper hand and causes the severe immune impairment that defines full-blown AIDS. This information comes from the Anthrax official website, the Typhus official website, and the HIV official website.