Bovine trypanosomiasis in dairy farming in the high tropics: First report of Haematobia irritans as the main vector for T. vivax and T. evansi in Colombia

Abstract

Bovine trypanosomiasis is a hemoparasitic disease transmitted in Latin America mainly by biting flies of the family Tabanidae. The study aimed to evaluate infection by <em>Trypanosoma vivax</em> and <em>Trypanosoma evansi</em> in cattle specialized in milk production on a farm and their potential vectors. A direct parasitological and entomological study was performed using microscopy techniques and polymerase chain reaction (PCR) with two molecular markers to differentiate <em>Trypanosoma</em> species in blood samples of cattle and flies. Infection frequency with <em>Trypanosoma vivax</em> and <em>Trypanosoma evansi</em> in cattle was 3.6 and 0%, respectively. Characterization of vectors shows <em>Haematobia irritans</em> as the most frequent fly in the study area (97.1%), followed by <em>Stomoxys calcitrans</em> (2.8%). No horseflies were identified. <em>T. vivax</em> and <em>T. evansi</em> were found in proboscis and thorax-abdomen of biting flies <em>Haematobia irritans</em> and <em>Stomoxys calcitrans</em>, representing an epizootic behavior, atypical in South American countries. Due to its high population density, it is suggested that the <em>Haematobia irritans</em> fly is the main potential vector.