“The human body louse is only a vector and not a reservoir because infected lice die five to seven days after they become infected with R. prowazekii. R. prowazekii multiplies in the gut epithelium of the louse which then detaches, ruptures, and releases rickettsiae into the feces. Rickettsiae from the infected feces enter the skin via abrasions or bite site and access the human host.”
Sami M. Akram; Vidhya Prakash.
See full article: “Rickettsia Prowazekii (Epidemic Typhus).”