Molecular characterization of trypanosomes commonly found in cattle, wild animals and tsetse flies in Kwazulu-Natal, South Africa, 2005-2007

Abstract

The objective of this study was to use molecular biological reagents (primers targeting different genomic loci) and methods (PCR and RFLP) to detect and characterize trypanosomes in cattle, wild animals and tsetse flies in KwaZulu-Natal, thus contributing to improved understanding of the genetic diversity of trypanosome species infecting cattle at the game/livestock interface in the KwaZulu-Natal Province of South Africa. Primers based on sequences of different loci in the trypanosome genome were used in conducting polymerase chain reactions (PCRs) on samples collected from cattle at 14 diptanks and one commercial farm around the Hluhluwe-Umfolozi Game Reserve, wild animals within Hluhluwe-Umfolozi Game Reserve and tsetse flies from the commercial farm, Hluhluwe-Umfolozi Game Reserve and two other Game Reserves. Trypanosome isolates were grown under laboratory conditions in cattle, rodents and culture medium for molecular characterizations. Overall, a total of 673 cattle, 266 tsetse flies, 141 buffaloes and 6 rhinoceros samples were analyzed. The following observations were made: two species of trypanosomes are present in KZN; T.congolense and T. vivax. The two species were found as single and as mixed infections in cattle. There are two genotypic groups of T. congolense in KZN; the Savannah- and the Kilifi-type. The two genotypic groups were found as mixed infections in cattle and in tsetse flies. Lastly, there are at least five “genomic variants” of Savannah-type T. congolense in KZN. The infection rate in cattle ranged from 5.2-91%; in tsetse flies, 11-97.5% and in wild animals it was 4.3%. Mixed infection of T. congolense and T. vivax were only observed in samples from one diptank. Mixed infections of Savannah- and Kilifi-type T. congolense were observed in samples from Boomerang commercial farm, and in tsetse flies. Copyright