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 maculopapular rash.
Head lice and body lice (Pediculus humanus) are similar in appearance, although the head lice is often smaller.
Vagabond's leukomelanoderma is a skin disorder found in the elderly with a combination of dietary deficiency and lack of hygiene, resulting in an infestation of Pediculus humanus.