AN OUTBREAK OF SARCOCYSTIS IN A COLLECTION OF PSITTACINES

Thirty-seven Old World psittacines at the San Diego Zoo died because of infection by a sporozoan parasite during a 15-mo period (1985-1986). One-half of the deaths were preceded by an acute illness. Light and electron microscopic studies identified the parasite as a species of Sar cocystis. Transmission of the disease to two budgerigars (Melopsittacus undulatus) and one cockatiel (Nymphicus hollandicus) was accomplished by gavage with purified gut scrapings from opossums (Didelphis virginiana), proving the opossum to be the definitive host. These findings suggested that the parasite is Sarcocystis falcatula (=debonei), a parasite of opossums and birds. Control measures, including trapping and relocation of opossums, have reduced mortality from this disease on zoo grounds.