Detection of Trypanosoma evansi in healthy horses, cattle and buffaloes in East Sumba: eight years after outbreak

Abstract

Trypanosoma evansi is a widespread hemoflagellate parasite that causes surra (trypanosomiasis) in a variety of mammal species, including horses, cattle, and buffaloes. In 2010-2012, the greatest outbreak of surra in Indonesia occurred on one of Indonesia's most remote islands, Sumba. This parasite has killed thousands of animals, particularly horses. The purpose of this study was to determine the prevalence of T. evansi infection in healthy livestock (buffaloes, cattle, and horses) after the 8th outbreak in East Sumba using different methods, including serological test (CATT/T. evansi), parasitological test (WBF, Giemsa-stained blood smears (GSBS), and Microhematocrit Centrifugation Test (MHCT), and molecular method by PCR. The survey was conducted during the arid season, when the population of vectors was at its lowest. Blood samples were taken from 111 animals in three subdistricts in East Sumba (Lewa, Wulla Waijelu, and Kota Waingapu). Results revealed that the infection rate of livestock with T. evansi varies by animal species and detection methods. No positive sampel found by Micro Hematocrit Centrifugation Test (MHCT), wet blood film (WBF), and Giemza-stained blood smears (GSBS). The overall infection prevalence according CATT/T.evansi and PCR were 7.2%(8/111) and 5.4% (6/111); respectively. The infection rates by CATT T.evansi and PCR were as follows: horse, 0/57 (0%) and 1/ 57(1.75%); buffalo 5/23 (21.7%) and 13.04% (3/23); cattle, 3/31 (9.7%) and 2/31(6.45%); respectively. Buffalo and cattle have a higher prevalence of T. evansi compared to horses. The results of the present study indicate that cattle and buffalo may serve as a reservoir for T. evansi, which poses a high risk to horses due to the virulence of Surra when vector populations are abundant.