Feudjio Soffack Steve, Melachio Tanekou Tito T, Nana Djeunga Hugues C, Farikou Oumarou, Kame Ngasse Ginette I, Tchami Mbagnia Mureille C, Wondji Murielle, Wondji Charles S, Khalil Hager, Abd-Alla Adly M M, Geiger Anne, Simo Gustave, Njiokou Flobert
Laboratory of Parasitology and Ecology, Faculty of Science, University of Yaoundé I, Yaoundé, Cameroon.
Department of Microbiology and Parasitology, Faculty of Science, University of Bamenda, Bamenda, Cameroon.
Insect Sci. 2025 Sep 7. doi: 10.1111/1744-7917.70160.
Sterile Insect Technique (SIT) has proven effective to reduce tsetse population density in large infected areas where animal African trypanosomosis (AAT) and human African trypanosomiasis (HAT) elimination was difficult to achieve. However, the decrease in mass production of insectary-reared tsetse and the limited but incomplete knowledge on symbiont-trypanosome interaction over time, impede large-scale use of SIT. We investigated the spatiotemporal changes in symbiont prevalence and symbiont-trypanosome interactions in wild tsetse of Sora-Mboum AAT focus in northern Cameroon, collected in 2019 and 2020, to provide insights into the mass production of refractory tsetse. Spiroplasma spp., Sodalis glossinidius and trypanosomes were screened with PCR. G. tachinoides was the most abundant Glossina species found in Sora-Mboum focus. Symbiont prevalences in G. tachinoides were higher in 2019 compared to 2020, from 67.6% to 53.5% for Spiroplasma spp. and from 28.8% to 8.1% for S. glossinidius. These symbionts were also found at higher prevalence in flies from Mouhoun HAT focus in Burkina Faso. Four trypanosome taxa (Trypanosoma congolense forest type, T. congolense savannah type, T. brucei s.l., and T. vivax) were found in Sora-Mboum focus and Mouhoun focus, though at lower prevalence in Mouhoun. The presence of Spiroplasma spp. in adult tsetse was negatively associated with that of trypanosomes. Our study highlights the potential of Spiroplasma spp. as a good paratransgenesis candidate to enhance SIT application. This symbiont is naturally found in high proportions of tsetse and could prevent factory flies from acquiring and transmitting trypanosomes during their lifespan when released for population density control.
昆虫不育技术（SIT）已被证明在难以实现动物非洲锥虫病（AAT）和人类非洲锥虫病（HAT）消除的大片感染地区，对于降低采采蝇种群密度是有效的。然而，随着时间的推移，昆虫饲养场饲养的采采蝇大规模生产数量的减少以及对共生体与锥虫相互作用的有限但不完整的认识，阻碍了SIT的大规模应用。我们调查了2019年和2020年在喀麦隆北部索拉 - 姆布姆AAT疫源地采集的野生采采蝇中共生体流行率和共生体 - 锥虫相互作用的时空变化，以深入了解难治性采采蝇的大规模生产。通过PCR筛选了螺旋体属、格氏嗜 Sodalis glossinidius 和锥虫。塔氏采采蝇是在索拉 - 姆布姆疫源地发现的最丰富的采采蝇物种。2019年塔氏采采蝇中的共生体流行率高于2020年，螺旋体属从67.6%降至53.5%，格氏嗜 Sodalis glossinidius 从28.8%降至8.1%。在布基纳法索穆洪HAT疫源地的采采蝇中也发现这些共生体的流行率较高。在索拉 - 姆布姆疫源地和穆洪疫源地发现了四种锥虫分类群（刚果锥虫森林型、刚果锥虫草原型、布氏锥虫复合种和活泼锥虫），尽管在穆洪的流行率较低。成年采采蝇中螺旋体属的存在与锥虫的存在呈负相关。我们的研究强调了螺旋体属作为增强SIT应用的良好共生转基因候选者的潜力。这种共生体在很大比例的采采蝇中自然存在，并且在为控制种群密度而释放时，可以防止工厂饲养的采采蝇在其生命周期内获取和传播锥虫。
