Cystoisospora belli (formerly Isospora belli ) has been renamed and included in the Cystoisospora genus. Both C. belli and Cyclospora spp. infect the small intestine and have been implicated in diarrheal disease. C. belli, which first was linked with disease…
Giardia intestinalis is a flagellated protozoan that infects the duodenum and upper small intestine. Giardia is the most commonly identified enteric parasite in the US and Canada. Infection can be asymptomatic or associated with a variety of intestinal manifestations. Factors…
In addition to Entamoeba histolytica ( Chapter 263 ), amebae that can be found in the human intestinal tract include other species of Entamoeba ( E. dispar, E. moshkovskii , E. bangladeshi, E. coli, E. hartmannii, E. polecki), Endolimax nana…
Entamoeba histolytica is a “tissue-lysing” ( histo = tissue, lytic = lysing) ameba that can cause disease ranging from asymptomatic colonization to diarrhea, colitis, and liver abscess. It was first discovered in 1875 by Fedor Aleksandrovich Lösch, who described amebic…
Endolimax nana is a single-celled parasite of the colon. Although considered nonpathogenic, infection with E. nana is an indicator of exposure to fecal contamination and often is seen in fecal samples positive for other common parasitic intestinal protists. Description of…
Human disease caused by Cryptosporidium was first described in 1976 and became recognized increasingly during the HIV epidemic. Improved detection of oocysts in feces has shown Cryptosporidium to be a common cause of diarrhea in both immunocompetent and immunocompromised hosts.…
Blastocystis is a protist that parasitizes the lower intestine of humans and a vast range of animals. Although Blastocystis has been implicated as a cause of various gastrointestinal tract symptoms, its role as a pathogen, mechanism of transmission, and life…
Balantioides coli originally was called Balantidium coli (synonym Neobalantidium coli ), but it has been renamed based on new phylogenetic observations. , This ciliate inhabits the intestine of several mammalian species, and it is the only ciliate known to infect…
Acknowledgment The author and editors remember the substantial contributions of Robert W. Tolan to pediatric infectious diseases and to this chapter in previous editions. Colleagues continue to mourn his loss. Babesiosis is an emerging tickborne zoonotic disease, clinically similar to…
Pediculosis The Parasites, Pathogenesis, and Epidemiology Pediculosis is an infestation by one of several species of sucking lice of the phylum Arthropoda, class Insecta, order Phthiraptera, suborder Anoplura, and family Pediculidae or family Pthiridae. The three types of lice that…