Jean-Marc Reifenberg

Comparison of the susceptibility of different Glossina species to simple and mixed infections with Trypanosoma (Nannomonas) congolense savannah and riverine forest types

Abstract Teneral Glossina morsitans mositans, G.m.submorsitans, G.palpalis gambiensis and G.tachinoides were allowed to feed on rabbits infected with Trypanosoma congolense savannah type or on mice infected with T.congolense riverine‐forest type. The four tsetse species and subspecies were also infected simultaneously in vitro on the blood of mice infected with the two clones of T.congolense via a silicone membrane. The infected tsetse were maintained on rabbits and from the day 25 after the infective feed, the surviving tsetse were dissected in order to determine the infection rates.

Molecular characterization of trypanosome isolates from naturally infected domestic animals in Burkina Faso

A total of 33 trypanosome cryostabilates isolated from domestic animals (bovine and dogs) were analysed using the polymerase chain reaction (PCR). The PCR was undertaken on diluted and treated buffy coat solutions according to an easy protocol of purification, using primers specific to Trypanosoma (Nannomonas) congolense of Savannah, Riverine-Forest, Kilifi and Tsavo types, T. (N) simiae, T. (Trypanozoon) brucei and T. (Duttonella) vivax. The results showed a lack of PCR sensitivity when target solutions were simply diluted, probably a reflection of the inaccuracy of the dilution procedure at very low trypanosome numbers. Nine mixed infections were found in purified samples whereas only three were detected in diluted crude solutions. T. congolense Savannah-type was present in all stabilates. Double infections involving this type with the Riverine-Forest type, T. vivax or T. brucei, were found. One stabilate was found to be infected with the three trypanosome types, namely T. congolense Savannah and Riverine-Forest genotypes and T. vivax. No infection attributable to T. congolense Kilifi and Tsavo types or T. simiae was detected in these stabilates. This work confirmed the abundance of mixed infections in the field, which could not have been detected by the classical parasitological methods. Amongst the T. congolense infections, the Savannah genotype was found to be predominant over the Riverine-Forest type; that could be a consequence of differences in genotype virulence in cattle. The detection of T. congolense Riverine-Forest type in vertebrate hosts living in wet areas could be confirmation of the suspected affinity of relationships between this taxa and the riverine forest tsetse fly species.

Trypanosome characterization by polymerase chain reaction in Glossina palpalis gambiensisand G.tachinoidesfrom Burkina Faso

Abstract. Following the discovery of four cases of African human trypanosomiasis, an entomological survey was conducted along the Mouhoun river in southwest Burkina Faso to collect Glossina palpalis gambiensisand G.tachinoides.Among 226 flies dissected, 4.87% (eleven individuals) were infected in midgut or proboscis, but never in the salivary glands. Polymerase chain reaction analysis was undertaken, and was able to characterize all the proboscis infections, and half of the midgut infections. Only Trypanosoma simiaeand T. vivaxwere found in the organs of infected flies, in single or mixed‐species infections. Ten more flies, negative with parasitological examination, were tested with Trypanozoonprimers and remained negative. The epidemiological significance of the absence of T.bruceigroup infections in wild tsetse populations and the presence of T.simiaein G.p.gambiensisare discussed.

Review on the Molecular Tools for the Understanding of the Epidemiology of Animal Trypanosomosis in West Africa

The epidemiology of animal trypanosomosis around Bobo-Dioulasso (Burkina Faso, West Africa) benefited a lot in the last years from the progress of molecular tools. The two most used molecular techniques were the polymerase chain reaction for the diagnosis of the disease in cattle and the characterization of the trypanosomes in the host and the vector on one hand, and the microsatellite DNA polymorphism in tsetse flies to study the intraspecific genetic variability of the vector on the other hand. The results obtained in the Sideradougou area during a recent two year survey with these techniques, associated with many other georeferenced informations concerning vector and cattle distribution, natural environment, landuse, ground occupation, livestock management, were combined in a Geographical Information System. This new approach of a complex pathogenic system led to a better evaluation of the risk of trypanosome transmission.

PCR Analysis and Spatial Repartition of Trypanosomes Infecting Tsetse Flies in Sidéradougou Area of Burkina Faso

ABSTRACT: A parasitological and entomological survey was conducted in the Sideradougou area (south of Bobo Dioulasso, Burkina Faso) in order to identify transmission factors of African trypanosomosis. A total of 3600 tsetse flies (Glossina tachinoides, Glossina palpalis gambiensis) were captured along 120 km of linear gallery forest and half of them were dissected. PCR analysis was undertaken on parasitologically positive flies (161 G. tachinoides, 92 G. palpalis gambiensis) to characterize the different trypanosomes. All the results were integrated in a GIS (Geographical Information System). Spatial repartition of the characterized trypanosomes enabled to recognize different areas with specific patterns of infection. Relations with environmental factors are discussed.