Trypanosoma evansi infection in Tunisia: current situation

Surra is a vector-borne disease, caused by a flagellate protozoan, Trypanosoma evansi, infecting all domestic mammals, including herbivores and dogs, and, very rarely, humans. In Tunisia, it affects mainly dromedaries (Camelus dromedarius) in the southern part of the country, causing heavy economic losses due to high morbidity, abortions and mortality. Trypanosoma evansi is mainly transmitted by mechanical vectors (Stomoxyine flies and tabanids), but also vertically, orally (to carnivores) and iatrogenically. In the present paper, we review and discuss the studies published on surra in Tunisia and show that the antibody seroprevalence in Tunisian dromedaries varies between 22.2% and 37%. The review also highlights the absence of a comprehensive database containing the most relevant information on the occurrence of T. evansi in Tunisia. We also underscore the urgent need for data collection and analyses. These data should be related to different aspects: epidemiological data (spatial and temporal distribution) and entomological data (main vectors involved in the transmission and their activity dynamics).