Vector control using larvicides is the main alternative strategy to address limits of preventive
chemotherapy using
ivermectin for the control of
onchocerciasis. However, it remains substantially limited by implementation difficulties, ecological concerns and the resistance of vector populations. Therefore, efficient and environmentally safe alternative control strategies are still needed. This study explores the composition of the blackfly bacteriome and its variability in the presence of Onchocerca volvulus
infection, in order to determine their potential as a novel vector control-based approach to fight
onchocerciasis. An entomological survey of a collection of samples was performed in the Bafia health district, a historical endemic focus for
onchocerciasis in Cameroon. A total of 1270 blackflies were dissected and the
infection rate was 10.1%, indicative of ongoing transmission of
onchocerciasis in the surveyed communities. Sequencing process of blackflies' gut
DNA for bacteria screening revealed 14 phyla and 123 genera, highlighting the diversity of gut blackflies bacterial communities. Eight bacteria formed the core of blackfly bacteriome and Wolbachia was the predominant genus with 73.4% of relative abundance of blackflies' gut bacterial communities. Acidomonas and Roseanomas genera were significantly abundant among infected blackflies (p = 0.01), whereas other genera such as Brevibacterium and Fructobacillus were associated with the absence of
infection (p = 0.0009). Differences in gut bacterial distribution of blackflies according to their
infection status by the parasite suggest a causal relationship between the bacteriome composition and the onset of blackflies'
infection by O.
volvulus or vice versa. Blackfly native bacteria are then potentially involved in
infection by O.
volvulus, either by facilitating or preventing the parasite infestation of the vector. These bacteria represent an interesting potential as a
biological tool/target for a novel approach of vector control to fight
onchocerciasis.