isospora isospora isospora is a genus of internal parasites in the subclass coccidia. isospora scientific classification domain: eukaryota clade: diaphoretickes clade: sar clade: alveolata phylum: apicomplexa class: conoidasida order: eucoccidiorida family: eimeriidae genus: isosporaschneider, 1881 species i. almaataensis i. anseris i. ashmoonensis i. bahiensis i. bigemina i. bronchocelae i. buteonis i. buteonis i. cardellinae i. hammondi i. heydorni i. hominis i. mandari i. mejiro i. neorivolta i. peromysci i. rara i. ratti i. rivolta i. thibetana i. wallacei it is responsible for the condition isosporiasis, which causes acute, non-bloody diarrhoea in immunocompromised individuals. taxonomy at least 248 species were originally described in this genus. for instance, the house sparrow has 12 species of isospora. however, most species are little studied, and some authors doubt whether all should be recognized as distinct species. in 2005, all former isospora species that infect mammalian hosts were reclassified as members of the genus cystoisospora, a member of the sarcocystidae family.