Brill–Zinsser disease is a delayed relapse of
epidemic typhus, caused by Rickettsia prowazekii. After a patient contracts epidemic typhus from the fecal matter of an infected
louse (Pediculus humanus), the
rickettsia can remain
latent and reactivate months or years later, with symptoms similar to or even identical to the original attack of typhus, including a
maculopapularrash.[1] At such times, typhus can be transmitted to other individuals through fecal matter of the louse vector, and generate a new
epidemic of the disease.[citation needed]