Prevalence of Loiasis Among Adults in Rural Communities of Benue State, North Central Nigeria

Loiasis caused by Loa loa is a filarial infection endemic to the forest zones of West and Central Africa, transmitted by Chrysops deer flies and characterised by subconjunctival worm migration, subcutaneous swelling, and occasional severe neurological complications during ivermectin therapy. This study surveys the prevalence of loiasis among adults in rural communities of Benue State, North Central Nigeria, which borders the forest-derived ecological corridor of the middle Benue valley. A cross-sectional parasitological survey was conducted in five rural communities in Oju, Obi, and Gwer-East Local Government Areas. Daytime blood samples were collected between 10:00 AM and 2:00 PM, and thick blood films were prepared and examined under microscopy for Loa loa microfilariae. Data on occupation, farm entry frequency, forest proximity, Chrysops fly bite history, and participation in community-directed treatment with ivermectin were collected. Current literature from 2020 to 2024 documents the importance of identifying high-density loiasis communities in Nigeria before mass drug administration with ivermectin to prevent Mazzotti-type encephalopathic reactions. This study generates microfilaria prevalence data and estimates the proportion of the community at risk for severe adverse events following ivermectin exposure. Findings will be submitted to the Benue State Ministry of Health and the African Programme for Onchocerciasis Control successor body for programmatic guidance. Keywords: loiasis, Loa loa microfilariae, rural communities, Benue State, ivermectin.