Background Trypanosomes cause disease in humans and livestock in sub-Saharan Africa and rely on tsetse flies as their main insect vector. Nigeria is the most populous country in Africa; however, only limited information about the occurrence and diversity of trypanosomes circulating in the country is available. Methods Tsetse flies were collected from five different locations in or adjacent to protected areas, i.e. national parks and game reserves, in Nigeria. Proboscis and gut samples were analysed for trypanosome DNA by molecular amplification of the internal transcribed spacer 1 (ITS1) region and part of the trypanosome specific glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH) gene. Results The most abundant Trypanosoma species found in the tsetse gut was T. grayi, a trypanosome infecting crocodiles. It was ubiquitously distributed throughout the country, accounting for over 90% of all cases involving trypanosomes. Trypanosoma congolense was detected in gut samples from all locations except Cross River National Park, but not in the proboscis, while T. brucei (sensu lato) was not detected at all. In proboscis samples, T. vivax was the most prominent. The sequence diversity of gGAPDH suggests that T. vivax and T. grayi represent genetically diverse species clusters. This implies that they are highly dynamic populations. Conclusions The prevalence of animal pathogenic trypanosomes throughout Nigeria emphasises the role of protected areas as reservoirs for livestock trypanosomes. The genetic diversity observed within T. vivax and T. grayi populations might be an indication for changing pathogenicity or host range and the origin and consequences of this diversity has to be further investigated.

BackgroundTsetse flies are vectors of trypanosomes, parasites that cause devastating disease in humans and livestock. In the course of vector control programmes it is necessary to know about the Glossina species present in the study area, the population dynamics and the genetic exchange between tsetse fly populations.ResultsTo achieve an overview of the tsetse fly diversity in Nigeria and at the Nigeria-Cameroon border, tsetse flies were trapped and collected between February and March 2014 and December 2016. Species diversity was determined morphologically and by analysis of Cytochrome C Oxidase SU1 (COI) gene sequences. Internal transcribed spacer-1 (ITS-1) sequences were compared to analyse variations within populations. The most dominant species were G. m. submorsitans, G. tachinoides and G. p. palpalis. In Yankari Game Reserve and Kainji Lake National Park, G. submorsitans and G. tachinoides were most frequent, whereas in Old Oyo National Park and Ijah Gwari G. p. palpalis was the dominant species. Interestingly, four unidentified species were recorded during the survey, for which no information on COI or ITS-1 sequences exists. G. p. palpalis populations showed a segregation in two clusters along the Cameroon-Nigerian border.ConclusionsThe improved understanding of the tsetse populations in Nigeria will support decisions on the scale in which vector control is likely to be more effective. In order to understand in more detail how isolated these populations are, it is recommended that further studies on gene flow be carried out using other markers, including microsatellites.

Tsetse fly and trypanosome prevalence in ruminants were estimated in April and August, peak months of the dry and rainy seasons in the Kachia Grazing Reserve (KGR) of Kaduna State, North Central Nigeria. This study was subsequent to reports of seasonal outmigration of semi nomadic Fulani from the grazing reserve due to death of cattle from trypanosomosis. Result of blood samples showed an overall parasitological infection rate of 17.4%. Infection rates in cattle, sheep and goats were, 18.6%, 9.5% and 5.1% respectively. Over all higher infection rate in the rainy season was attributed to abundance of tsetse and other hematophagus flies. Infection rate in younger animals (21.9%) was higher compared to those of older animals (16.5%). Trypanosoma vivax was the dominant infecting trypanosome specie followed by T. congolense and T. brucei.It was concluded that tsetse fly and trypanosomosis constituted dual plagues limiting economic livestock production and settling of the pastoralists in the grazing reserve. This warrants application of sustainable integrated control measures to enhance utilization of abundant fodder at the reserve.

Field tests were carried out to compare the performance of a new tsetse trap, the Nitse (I and II) with the biconical, F, and NGU traps respectively at the Yankari Game Reserve, Bauchi State, Nigeria. The game reserve harbours Glossina palpalis, G. tachinoides and G. morsitans submorsitans species. The biconical trap was used as the standard. The sites had been cleared of vegetation; they were 5-10 m away from vehicle paths and about 100 m apart. Each trap was moved rotatingly until all traps were exposed to each of the five sites. Traps were emptied each morning after 24 h and the tsetse sorted according to species and sex. The data on the different trap catches were analysed using the one-way ANOVA and the multiple range test via the SPSS statistical package. The performance of the Nitse I on G. tachinoides in one area with high tsetse density was significantly better than that of each of the three traps. But for G. m. submorsitans, Nitse I and the biconical trap performed better than only the F 3 (P < 0.05) in the high density area. Only the biconical performed significantly better than the F 3 trap in an area with low tsetse density. The new Nitse trap was more effective for G. tachinoides than for G. m. submorsitans.Resume-On fit les epreuves aux champs pour evaluer l'accomplissement du piege Nitse (I et II), un nouveau piege, aupres des pieges biconiques, F-, et NGU respectivement a la reserve des animaux a Yankari, l'etat de Bauchi, au Nigeria, la ou les especes des mouches Glossina palpalis, G. tachinoides et G. morsitans submorsitans existent. On a utilise le piege biconique comme le piege de modele de I'etude. On a place les pieges en emplacements differents de vegetation abbatrie separes de 100 m et 5-10 m au toin des chemins de vehicule. On a place les pieges en tous les cinq emplacements I'un apres I'autre. 24 heures d'apres, on a decharge les pieges chaque matin et trie les mouches attrapees selon l'espece et le sexe. On a analyse les donnees des pieges differents en utilisant le one-way ANOVA et l'essai de champ d'activite de multiple par un emballage statistique de SPSS. Le piege Nitse I a accompli mieux d'une maniere significative au sujet d'attraper G. tachinoides a la region A que chacun des autres pieges. Nitse I et le piege biconique ont attrape mieux G. m. submorsitans que le F, (P < 0.05) a la region de grande densite. Le piege biconique seulement a accompli mieux d'une maniere significative que le piege F, a la region de petite densite (B). Nitse, le nouveau piege, etait plus efficace pour attraper G. tachinoides que pour attraper G. m. submorsitans.

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