Typhus: Uncommon Disease, Commonly Said

Typhus refers to a group of infectious diseases that are caused by rickettsial organisms and result in an acute febrile illness. Epidemic typhus is the prototypical infection of the typhus group of diseases, and the pathophysiology of this illness is representative of the entire category. The arthropod vector of epidemic typhus is the body louse (Pediculus corporis). This is the only vector of the typhus group in which humans are the usual host. Humans are accidental hosts in other type of typhus; rats, mice, and larger mammals are the usual hosts.

Typhus patients should have exposure to an endemic area, or occupational exposure (medical and military personnel are potentially at higher risk than the general population in endemic areas). Overcrowding leads to close personal contact and spread of arthropod vectors (particularly lice) among individuals. And lack of personal hygiene: Infrequent bathing and changing of clothes provides a hospitable environment for body lice.

Rickettsia prowazekii, which is the etiologic agent of typhus, lives in the alimentary tract of the louse. A Rickettsia-harboring louse bites a human to engage in a blood meal and causes a pruritic reaction on the host's skin. The louse defecates as it eats; when the host scratches the site, the lice are crushed, and the Rickettsia-laden excrement is inoculated into the bite wound. The Rickettsia travel to the bloodstream and rickettsemia develops.

And at last we know the brief explanation of the difference between typhoid fever and typhus