Molecular epidemiological studies of concurrent Trypanosoma species infections in man, cattle and tsetse in northern Cameroon

Description

This book reveals the diversity and complexity of Trypanosoma species circulating in Dodeo, a rural area of northern Cameroon (Central Africa); where there is frequent interaction of man and livestock with tsetse flies. Several pathogenic trypanosomes have to colonise the gut of tsetse before they further develop into infectious forms. Therefore, we investigated the presence of trypanosomes in gut and proboscis tissue, cattle and humans by PCR targeting conserved sequences in the ITS1 regions of Kinetoplastidae DNA as well as gGAPDH; subcloning and sequencing of representative amplicons. Taking advantage of molecular sequence data, their evolutionary relationships within the Trypanosomatidae family was studied. The variety of trypanosomes reported in this book might become potential pathogens in hosts. In intense, Trypanosoma grayi previously reported as a parasite of reptile exclusively, was found in cattle correlating with PCVs values at pathological levels. T. grayi might be undergoing a change in host range since all previous trials to infect mammals with T.grayi were not successful, as discussed by Hoare (1929), and in particular as specific primers designed from T. grayi ANR4 in the database were used to identify this parasite even in the proboscis. This unexpected finding reports thus the first evidence of this parasite in mammals. Variants of T. congolense, termed T. congolense-like were identified in man, which is surprising as human are known to possess an innate immunity against the animal trypanosome species due to their susceptibility to trypanolytic factors present in human serum. This could be a strain of T. congolense which is on its way to adapt to humans as definitive hosts; characteristic of a zoonotic parasite. This is consistent for T. congolense transsialidases (TconTS) revealed themselves to be immunogenic to humans with T. congolense DNA, thus underlining the first report of atypical trypanosome species occurring in man in Cameroon, and in Central Africa.