Abstract:
African animal trypanosomosis (AAT), is an infectious parasitic disease of wildlife and
livestock caused by multiple species and strains of Trypanosoma. In South Africa, it is restricted
to northern KwaZulu-Natal (NKZN) and caused by Trypanosoma congolense and Trypanosoma vivax.
A cross-sectional study was done to determine AAT prevalence in 384 goat samples and identify
trypanosome species circulating in 60 cattle at dip tanks that are on the interface with the HluhluweuMfolozi
game reserve in NKZN. Both cattle and goat samples were analyzed using the buffy coat
technique (BCT) and a polymerase chain reaction (PCR) assay targeting the internal transcribed
spacer 1 (ITS) region. Cattle samples were further analyzed using an ITS quantitative real-time
PCR (qPCR) assays designed for the detection of T. congolense, T. vivax, and T. brucei. None of the
goat samples tested positive for Trypanosoma infections. The ITS qPCR assay detected Trypanosoma
DNA in 30% of the cattle samples, while only 8.3% were positive with the ITS PCR and 11.7% were
positive using BCT. Quantitative real-time PCR assays were designed to amplify a 98 bp, 137 bp,
and 116 bp fragment of the cathepsin L-like (CATL) gene from T. brucei, T. theileri, and T. congolense,
respectively. Each assay was shown to be efficient (>94%) and specific (109 to 102/101 copies/reaction)
in the detection of Trypanosoma species. The CATL qPCR assays detected T. congolense and T. theileri
infections in 33.3% of the cattle samples. The CATL qPCR assays also detected T. congolense infections
in goats (23.1%) that were neither detected by BCT nor the ITS PCR. The CATL qPCR assays provide
an additional, sensitive, and specific tool for Trypanosoma diagnostics. The presence of trypanosomes
in goats suggests they might be potential reservoirs of infections to other livestock.
