The University of Georgia College of Veterinary Medicine

eorgia Veterinary Scholars Program

GVSP Summer 2008 Scholars

Georgia Veterinary Scholar	Faculty Mentor

Mason Savage University of Georgia Class of 2011	Dr. Michael Yabsley

Characterization of Trypanosoma cruzi from the United States

Savage, Mason*. Roellig, Dawn; and Yabsley, Michael. Southeastern Cooperative Wildlife Disease Study, Department of Population Health, College of Veterinary Medicine, University of Georgia, Athens, Georgia 30602

Trypanosoma cruzi, a protozoan parasite, is the etiologic agent of Chagas Disease. This parasite is widespread in the Americas and causes nearly 50,000 deaths annually in Latin America. Although infections with T. cruzi are known to be common in wildlife in the United States, cases in people and domestic animals
are uncommon. The objective of this study was to characterize isolates of T. cruzi obtained from a variety of hosts and geographic regions of the United States. Amplification and/or sequencing of several genetic targets were used to classify the US strains into one of the two T. cruzi genotypes (type I or type II). A total of 11 isolates from the United States and a Type I human isolate from Brazil were included in the study. Two of the 11 United States isolates were classified as type I (both from Virginia opossums, Didelphis virginiana), eightwere classified as type II (subtype IIa) (from six raccoons (Procyon lotor), a ring-tailed lemur (Lemur catta),
and a domestic dog), and a single isolate from a domestic dog was classified as type I/IIa due to its possession of genetic characteristics of both genotypes (likely representing a mixed culture of both strains). Growth rates of the epimastigote form in LIT medium (stage of the parasite found in vectors) varied significantly between isolates. Although all isolates exhibited peak growth between days 12 and 19, the two type I isolates and the apparent mixed infection achieved higher numbers of parasites/ml at their growth peaks. All isolates were able to invade and replicate in a canine macrophage cell line and cell invasion, replication, and release rate assays for the various isolates are currently underway and will be presented.

Research Support: NIH/NIAID R15 AI067304-01A1.

Student Support: NIH 5 T35 RR022685.