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Saurian and Avian Malaria Parasites
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Jos. J Schall
Department of Biology University of Vermont Burlington, VT 05405 Joseph.Schall@uvm.edu |
Since 1978, J. J. Schall and his students have explored the biology of malaria parasites, with studies of species that exploit reptiles and birds as their vertebrate hosts. The term "malaria parasite" is used here for apicomplexans in the genera Plasmodium, Haemoproteus, and Leucocytozoon. Sites for the study of lizard malaria parasites include a long-term project at the UC Hopland Research and Extension Center, near the town of Hopland in Mendocino County California; the Long-Term Ecological Research site at El Verde in eastern Puerto Rico; and the tiny Caribbean islands of Saba and St. Martin. A major project was done years ago in Sierra Leone, west Africa. The eastern Lesser Antilles have provided an excellent system for studies in the biogeography and phylogeography of lizard malaria in Anolis. The first goal of the overall project was to determine the virulence of Plasmodium in lizard hosts, in which an inventory was made of the full range of pathology and reproductive costs of P. mexicanum for fence lizards at Hopland and three Plasmodium species infecting the endemic anole of Saba. Other topics pursued include long-term trends in prevalence at three sites, the dynamics of natural and induced infections, transmission biology and vector ecology at Hopland, and the life history traits of the parasite. In more recent years, the powerful techniques of molecular biology have opened new lines of investigation. The systematics of malaria parasites was studied, resulting in the largest molecular phylogeny ever presented. Phylogeographic studies followed for the Caribbean islands. A set of variable genetic markers (microsatellites) for P. mexicanum have been characterized, and ongoing studies examine the clonal diversity of infections and effect of clonal diversity on the parasite's life history and virulence. Blood samples collected from infections over more than a quarter century at Hopland are used to follow changes in the genetic makeup of the parasite over time. In recent years, the biodiversity and host range of avian malaria parasites has been studied in Vermont, California, and Israel. Vermont is an excellent location to sample a large number of bird species because it is on the flyway for migration, and also is the intersection between more alpine, boreal and southern habitats. Also, Vermont is quite large, larger than Switzerland, and almost as large as Belgium. The goals of these studies are to define the true diversity of the parasites, recover their phylogeny, examine the value of morphology vs. gene sequences in identifying the parasites, and understanding the parasite's host range. Three genera of interest: Plasmodium, Haemoproteus, and Leucocytozoon. This site provides details on techniques, a list of publications resulting from the studies, a synopsis of research results, and photographic albums of the parasites of lizards and birds. Information on the current lab group and previous students and their projects is also given. |
  Site construction funded by the Morris Animal Foundation |