Rodent-borne Trypanosoma from cities and villages of Niger and Nigeria: A special role for the invasive genus Rattus?

Although they are known to sometimes infect humans, atypical trypanosomes are very poorly documented, especially in Africa where one lethal case has yet been described. Here we conducted a survey of rodent-borne Trypanosoma in 19 towns and villages of Niger and Nigeria, with a special emphasis on Niamey, the capital city of Niger. The 1298 rodents that were captured yielded 189 qPCR-positive animals from 14 localities, thus corresponding to a 14.6% overall prevalence. Rats, especially black rats, displayed particularly elevated prevalence (27.4%), with some well sampled sites showing 40-50% and up to 68.8% of Trypanosoma-carrying individuals. Rattus were also characterized by significantly lower Ct values than in the other non-Rattus species. DNA sequences could be obtained for 43 rodent-borne Trypanosoma and corresponded to 41 T. lewisi (all from Rattus) and 2 T. microti (from Cricetomys gambianus). These results, together with data compiled from the available literature, suggest that Rattus may play a particular role for the maintaining and circulation of Trypanosoma, especially T. lewisi, in Africa. Taken into account its strong abilities to invade coastal and inland regions of the continent, we believe that this genus deserves a particular attention in regards to potentially under-looked but emerging atypical trypanosome-related diseases.