Experimental studies on the life cycle of a renal coccidium of lesser snow geese (Anser c. caerulescens)

Abstract

Lesser snow geese (Anser c. caerulescens), gadwall (Anas strepera), mallards (A. platyrhynchos), and blue-winged teal (A. discors) were raised artificially under minimal coccidiosis conditions (no coccidia were found in their feces prior to infection). Oocysts were obtained from the ureters of heavily infected wild juvenile lesser snow geese, sporulated, and orally administered to experimental birds. In lesser snow geese, oocysts were passed in the feces, beginning on postinoculation day (PID) 9 ± 1 and continuing for a further 34–35 days. Peak oocyst production occurred on PID 11 and 12. The morphology of the oocyst was described. Pathogenic effects on experimentally infected lesser snow geese included mild diarrhoea, slight anorexia, polydipsia, and increased salt gland discharge. Kidneys were enlarged, pale, and covered with 1- to 2-mm whitish nodules which, along with the ureters and lumina of renal tubules, contained many oocysts. This coccidium did not produce patent infections in the ducks listed above. Domestic geese (Anser anser domesticus), infected with numbers of oocysts similar to those used for lesser snow geese, passed few oocysts, beginning on PID 11 and continuing for a few days. Because of the inconsistencies in reports of Eimeria truncata in waterfowl, further study is essential before the species identity is determined.