Pentastomiasis.

Pentastomiasis is a parasitic zoonosis caused by pentastomes, members of an unusual phylum--Pentastomida--with characteristics of both arthropods and annelids. Adult pentastomes parasitize the respiratory tracts of reptiles or carnivorous mammals. The infection is generally limited to the tropics and subtropics, but ocular involvement has been reported in the southern United States. The majority of human pentastomiasis is caused by two species. The first, Armillifer armillatus, infects humans as secondary hosts. Infection is usually asymptomatic but has characteristic postmortem and radiologic features. The second, Linguatula serrata, can infect humans as does Armillifer or can cause a self-limited nasopharyngitis--the halzoun or marrara syndrome--with the human acting as a temporary definitive host. This article discusses the biology and parasitology of these metazoans as well as the clinical manifestations, pathology, diagnosis, and epidemiology of pentastomiasis.