Intestinal nematode infections are caused by a group of helminths, sometimes referred to as soil-transmitted nematodes, soil-transmitted helminths, or geohelminths. They are among the most common parasitic infections in humans and affect more than one-seventh of the world’s population. In…
Organisms of the genus Trypanosoma are flagellated protozoan parasites that inhabit the blood and tissue of a wide variety of vertebrate hosts, including birds, reptiles, and mammals. The name is derived from the Greek, trypano (meaning auger, a helical shaped…
Trichomonas vaginalis can infect both men and women and is recognized as the most common nonviral sexually transmitted infection in the world. Description of The Pathogen T. vaginalis , a flagellated protozoan parasite, was first described in 1836 by French…
Toxoplasma gondii , a parasite with worldwide distribution, is responsible for a significant disease burden in humans. Primary infection can be asymptomatic, mildly symptomatic with a mononucleosis like illness and/or lymphadenopathy, or it can cause severe ocular disease, even in…
Sarcocystis species are zoonotic protozoan parasites of the phylum Apicomplexa. Since its first description in 1843, >150 species have been reported from a range of wild and domestic mammals, birds, and reptiles. The organism requires a definitive host and an…
Acknowledgment Paul M. Arguin is acknowledged for substantial contributions to this chapter in previous editions. Although malaria is a major cause of morbidity and mortality in the world, most cases in the United States and Europe occur in people who…
Description of Pathogen Acanthamoeba are a genera of free-living amebae that can cause localized infection of the central nervous system (CNS), respiratory tract, skin, eyes, and disseminated disease. Nearly 25 named species and at least 20 genotypes of Acanthamoeba have…
Description of the Pathogen Naegleria fowleri is a free-living ameba that causes primary amebic meningoencephalitis (PAM). , It is the only known species of the genus Naegleria pathogenic to humans amongst over 40 other identified species. Two other species, N.…
Before 1985, few human microsporidial infections had been reported. Since then, the number of cases has increased dramatically because of recognition of this pathogen in patients infected with HIV. Although most reported infections have occurred in HIV-infected people, the organism…
Description of the Pathogen The genus Leishmania comprises vector-borne protozoan parasites that cycle asexually between the digestive tract of the sand fly as a motile flagellated promastigote and, in a wide range of vertebrate hosts (e.g., rodents, canids, hyrax, humans),…