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Definition

Several different illnesses called "typhus" exist, all of them caused by one of the bacteria in the family Rickettsiae. Each illness occurs when the bacteria is passed to a human through contact with an infected insect.

Description

The four main types of typhus are:

• epidemic typhus
• Brill-Zinsser disease
• endemic or murine typhus
• scrub typhus

These diseases are all somewhat similar, although they vary in terms of severity. The specific type of Rickettsia that causes the disease also varies, as does the specific insect that can pass the bacteria along.

Epidemic 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 carry the...