Development of Caryospora bigenetica n. sp. (Apicomplexa, Eimeriidae) in Rattlesnakes and Laboratory Mice1

Abstract

During a survey of the coccidian parasites of reptiles from Iowa, three specimens of Crotalus horridus L., the Timber Rattlesnake, and one of Sistrurus catenatus (Rafinesque), the Massasauga Rattlesnake, were found to be passing oocysts of a Caryospora, here described as C. bigenetica n. sp. Since these snakes (family Crotalidae) are known to subsist mainly on small mammals, oocysts from one of the Timber Rattlesnakes were fed to laboratory white mice (Mus musculus L.) to determine if mammals might be involved as alternate hosts in the life cycle. At necropsy, tissues of the tongue and dermis of the mice revealed a sequence of stages which included mature male and female gamonts, fully sporulated sporocysts, “excysted” sporozoites, and “resting” sporozoites that lay individually in solitary, cyst‐like host cells termed “caryocysts.” A coccidia‐free Massasauga that was fed an infected mouse, at a time when caryocysts in the mouse would have been present, later passed oocysts similar to those of the original inoculum. These results, along with the discovery of endogenous stages (asexual and sexual) in the intestine of the Timber Rattlesnake and the experimentally infected Massasauga, suggest that this parasite has a heteroxenous life cycle pattern, with sexual stages occurring both in the ophidian and the mammalian hosts.

Avispora mochogalegoi n. sp. (Apicomplexa: Sarcocystidae) in the little owl, Athene noctua (Strigiformes: Strigidae), in mainland Portugal

“…In fact, previous studies had already highlighted the evident morphological and biological differences of Caryospora spp. found in raptors and reptiles, such as the presence of a Stieda body and developmental details in the intermediate host, especially regarding caryocysts, along with the evident host specificity (CAWTHORN & STOCKDALE, 1981;WACHA & CHRISTIANSEN, 1982;UPTON et al, 1986;BERTO et al, 2014).…”

Caryospora varaniornati sp. n. (Apicomplexa: Eimeriidae) in the Nile monitor, Varanus (Polydaedalus) niloticus species complex

“…Two species infecting viperid snakes, Caryospora bigenetica and C. simplex, have been found to have heteroxenous life-cycle pattern involving rodents as the so-called secondary hosts (Wacha and Christiansen 1982, Upton et al 1984b, Upton and Barnard 1988. SCID mice were previously shown to be an optimal model for testing the heteroxenous life-cycle pattern of C. simplex from viperid snakes , Vítovec et al 1997.…”

Caryospora matatun. sp., a new coccidian parasite (Apicomplexa: Eimeriidae) from the horned bush-viper,Atheris ceratophorusWerner, 1895 from Tanzania

“…However, experimentally studied Caryospora spp. from vipers and rattlesnakes possess a distinct heteroxenous mode of the life cycle (Koudela, 199.3;Wacha & Christiansen, 1982). An oocyst infection leads to a dermal caryosporosis and a development of subcutaneous caryocysts in a secondary hosts, i.e.…”

“…An oocyst infection leads to a dermal caryosporosis and a development of subcutaneous caryocysts in a secondary hosts, i.e. rodents (Koudela, 1993 Upton & Barnard, 1988;Wacha & Christiansen, 1982). Recently, a severe combined immunodeficient (SCID) mice were used and suggested as a model for testing the heteroxenity of Caryospora spp.…”