PARASITE DIVERSITY IN AN ENDEMIC REGION FOR AVIAN MALARIA AND IDENTIFICATION OF A PARASITE CAUSING PENGUIN MORTALITY

Understanding the population structure of Plasmodium parasites is esse ntial for malaria intervention. A survey of parasites in vectors and h ost infections was conducted in an area of intense mortality due to ma laria in a captive penguin (Spheniscus demersus) colony, using a novel method for identification of Plasmodium species by amplification of r ibosomal sequences in DNA or RNA. Three phylogenetically distinct grou ps of avian Plasmodium were detected in mosquitoes (Culex) collected a t the study site (Baltimore Zoo, Baltimore, MD) during a period of hig h transmission. One of the three clades of Plasmodium was found to be prevalent in penguins monitored through the malaria transmission seaso n and consistent with morphological identification as Plasmodium relic tum. This parasite sequence was directly associated with the death of a penguin. Thus, a complete transmission cycle is defined at this site . Phylogenetic comparison of ribosomal sequences to an authenticated r eference strain of Plasmodium relictum indicates that this is not the parasite causing death in the penguins, suggesting that different para sites may be morphologically indistinguishable.