Authors

Discussion

species of Trypanosoma transmitted by the tsetse fly (Glossina) vector are responsible for clinically significant diseases in both human and animal populations. Although significant advances have been made in the control of human African trypanosomiasis (HAT), animal African trypanosomiasis (AAT) remains a disease of significant economic burden and livestock mortality in sub-Saharan Africa. Current AAT surveillance tools suffer from poor sensitivity and specificity, with serological methods also requiring animal restraint and blood collection by trained personnel. Faecal sampling is an attractive potential option for more accessible sample collection and screening. Therefore, this study set out to determine in the first instance whether it is possible to detect DNA of an AAT aetiological agent (T. brucei) in the faeces of experimentally-infected cattle. Five male Holstein-Friesian calves of post-weaning age were inoculated with T. brucei AnTat 1.1 and the infection course was followed for a total of 68 days. A total of 146 faecal samples (12 pre-infection, 134 post-infection) were passively collected and screened using PCR and a novel probe-based qPCR assay targeting a Trypanozoon-specific repeat region in kinetoplast minicircle DNA. Target DNA was successfully detected in 85% (n=114) of post-inoculation faecal samples by qPCR and 50% (n=67) by PCR. Target DNA was detected in samples collected between four days post-inoculation (dpi) to 66 dpi by both qPCR and PCR. Amplification of target DNA was confirmed by Sanger sequencing of PCR products, which revealed significant homology to the target sequence. These results confirm, for the first time, the ability to consistently detect Trypanosoma DNA from the faeces of infected cattle. This opens up the potential to use faeces as an easily accessible sample to screen for active AAT infection in cattle and potentially wild mammalian hosts. Future research should be directed at this novel diagnostic approach as a potential tool to improve AAT surveillance.