Atoxoplasma is a genus of parasitic alveolates in the phylumApicomplexa. The species in this genus infect birds. They are spread by the orofaecal route.
History
This genus was created by Garnham in 1950. The history of this genus has been plagued with confusion. Before 1909 the species in this genus were confused with those of the genus Haemoproteus. Between 1909 and 1937 they were considered to be species of the genus Toxoplasma. It was because of this historical confusion with Toxoplasma that Garnham chose the name Atoxoplasma for this genus.
Garnham defined this genus to be those parasites that infect the monocytes of birds, are strictly host specific, have a granular cytoplasm and a large nucleus. His choice of type species Atoxoplasma avium was later shown to be a junior synonym of Atoxplasma paddae. Lainson in 1958 published a study suggesting that these species were transmitted by ticks and that this genus was a synonym of Lankesterella - a genus of species that infects frogs.[1]
The genus later became regarded as a junior synonym of the genus Isospora for those species that infect birds.[2]
Definition
The species in this genus develop asexually in both the blood and intestinal cells and form oocysts that are passed unsporulated in the feces, sporulate on the ground which then infect new hosts.[3] The oocysts are tetrasporozoic, diplosporocystic and possess Stieda bodies in their sporocysts.[4]
Life cycle
The encysted sporozoites are ingested. The sporozoites decyst and invade the intestinal wall and from there reach the liver and other tissues including the blood cells where they replicate asexually. Within the intestine they undergo sexual reproduction, undergo gametogony and fertilization. The zygotes undergo division and form cysts which are passed out with the stool.
^Lainson R (1958) Some observations on the life-cycle of Atoxoplasma, with particular reference to the parasite's schizogony and its transmission by the mite Dermanyssus gallinae. Nature 182(4644):1250-1251
^Barta JR, Schrenzel MD, Carreno R, Rideout BA (2005) The genus Atoxoplasma (Garnham 1950) as a junior objective synonym of the genus Isospora (Schneider 1881) species infecting birds and resurrection of Cystoisospora (Frenkel 1977) as the correct genus for Isospora species infecting mammals. J Parasitol 91(3):726-727
^Levine ND (1982) The genus Atoxoplasma (Protozoa, Apicomplexa). J Parasitol 68(4):719-723
^Barta JR, Schrenzel MD, Carreno R, Rideout BA (2005) The genus Atoxoplasma (Garnham 1950) as a junior objective synonym of the genus Isospora (Schneider 1881) species infecting birds and resurrection of Cystoisospora (Frenkel 1977) as the correct genus for Isospora species infecting mammals. Parasitol 91(3):726-727
