Community Perceptions of Blackfly Nuisance and Acceptability of the "Slash and Clear" Vector Control Approach in the Ntui Health District of Cameroon: A Qualitative Study.

Besides being vectors of the onchocerciasis parasite, blackflies are a source of nuisance in onchocerciasis-endemic communities. We investigated the experience of residents in the Ntui Health District (Cameroon) regarding blackfly nuisance and assessed their perceptions of a novel "Slash and Clear" (S&C) intervention for blackfly control. Focus group discussions were conducted before and after S&C implementation (respectively, in February 2022 and December 2023). Blackflies were known to emerge from the river areas and cause disease. To prevent blackfly bites, the population often covered their body with protective clothing and applied various substances (kerosene, oil, or lemon) to their skin. Post-intervention data showed reduced blackfly nuisance, and the willingness to sustain blackfly control in the long-term was unanimous among community leaders and members, including the village volunteers who implemented the S&C intervention. In conclusion, blackfly nuisance is evident in the Ntui onchocerciasis focus of Cameroon and led to a panoply of coping practices, some of which could be detrimental to their health. Implementing S&C for blackfly control is well accepted and could sustainably alleviate the nuisance caused by blackflies while simultaneously breaking the onchocerciasis transmission cycle.

Association Between Ov16 Seropositivity and Neurocognitive Performance Among Children in Rural Cameroon: a Pilot Study.

Infection with Onchocerca volvulus was recently reported to increase the risk for epilepsy in Cameroonian children. We investigated whether infection with O. volvulus may alter the cognitive function of children who may or may not develop epilepsy later in their lifetime. Using rapid diagnostic tests, we determined the presence of Ov16 antibodies in 209 school-aged children without epilepsy recruited from three Cameroonian villages, as a proxy for onchocerciasis exposure. In addition, the neurocognitive performance of these children was assessed using a battery of validated tools. Participants were aged 6-16 years, and 46.4% were Ov16 seropositive. Upon standardizing age-specific neurocognitive scores and investigating predictors of neurocognitive performance using multiple linear regression models (adjusted for gender, education level, previous ivermectin use, and anthropometric parameters), we found that being Ov16-positive was significantly associated with reduced semantic verbal fluency (estimate -0.38; 95% confidence interval -0.65 to -0.11; p = 0.006) and lower scores on the International HIV Dementia Scale (estimate -0.31; confidence interval -0.56 to -0.04; p = 0.025). Furthermore, an increasing frequency of past ivermectin use was associated with increased neurocognitive scores. Our findings suggest that exposure to O. volvulus may affect neurocognitive performance of children. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40817-021-00111-z.