SENSITIVITY OF DIAGNOSTIC TECHNIQUES IN DETERMINING THE PREVALENCE OF ANURAN TRYPANOSOMES

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Abstract
Leopard frogs (Rana pipiens) (233) from Oshkosh, Wisconsin, USA, were divided into 2 groups and their blood examined for trypanosomes. In group 1 (n = 157), where the blood was examined by the hematocrit centrifuge technique (HCT); 36 (23%) were infected with trypanosomes. Of these, 18 were infected with Trypanosoma pipientis, 13 with T. ranarum, 3 with T. rotatorium and 2 with mixed infections of T. pipientis and T. ranarum. In group 2 (n = 76), the blood was cultured and also examined by HCT and wet mounts. Trypanosomes (T. pipientis and T. ranarum) were detected in 24 frogs (33%) using all 3 techniques. T. pipientis (11) were detected by HCT; none were detected by culture and 2 by wet mounts. T. ranarum (12) were detected by culture while only 10 were found by HCT and 5 by wet mounts. One T. ranarum infection detected by HCT was missed by culture because of bacterial contamination. The HCT was consistently better than wet mount examinations. It is suggested that the HCT be used whenever possible in future trypanosome surveys.