Biting preferences of blackfly in two endemic communities of ose local government area, Ondo state, Nigeria

Context: Blackflies are hematophagous dipterans who transmit Onchocerca volvulus; the pathogen of onchocerciasis. Aims: The study was undertaken in Imeri and Idogun to evaluate the knowledge of respondents on the biting preferences of blackflies. Settings and Design: The design is an observational study in epidemiology which involves the use of structured questionnaire to obtain useful epidemiological information from the respondents. Materials and Methods: Structured questionnaire was administered during personal interview and focus group discussion to obtain useful epidemiological information. Statistical Analysis Used: Data obtained were analyzed using Carl Pearson Chi-square at P < 0.05 level of significance. Results: The results showed that only 193 of the 578 respondents interviewed in the two communities had adequate knowledge of the cause and mode of transmission of onchocerciasis. This group knew that the disease is transmitted by the bite of infected blackflies. Other respondents (66.6%) had wrong perception about the cause and mode of transmission of the disease. The wrong perceptions observed in the communities include transmission by sexual intercourse, stepping on charms, and transmission from infected parent to offspring. The knowledge on the biting preference of the blackflies as tested among 193 respondents that were knowledgeable about the disease varied significantly (P = 0.05). Some respondents believed the fly bites in the farm (48.7%) and others believed the fly bites by the riverside (36.3%), in the village (5.2%), whereas 9.8% of the respondents believed the fly bites both on the farm and the riverside. Similarly, others believed the fly bites on the exposed legs (54.4%), hands (9.9%), and face (6.7%). Meanwhile, 29% of respondents believed the fly bites on any exposed part of the body. Conclusions: The results revealed that ignorance on the bioecology of the vector is still very high in these communities.