The intermediate host spectrum in a Sarcocystis species of birds.

The life cycle of an avian Sarcocystis has been completed in the laboratory, originating with naturally infected icterids and passing alternately between opossums (Didelphis virginiana) and experimentally infected birds. To determine the intermediate host range, six avian species, including canaries (Serinus canarius), zebra finches (Poephila guttata), budgerigars (Melopsittacus undulatus), pigeons (Columba livia), chickens (Gallus gallus), and guinea fowl (Numida meleagris), were inoculated orally with Sarcocystis sporocysts derived from experimentally infected opossums. All birds but the Galliformes were susceptible to merogony. Pigeons (Columbiformes) were susceptible to early merogony but apparently not to muscle stages. Passeriformes and Psittaciformes were completely susceptible and the parasite developed into muscle cysts in them.