Prevalence of Loiasis Among Forest Communities in Cross River State, South South Nigeria

Loiasis, caused by the filarial nematode Loa loa, is a neglected tropical disease transmitted by Chrysops flies in forested zones of West and Central Africa. This cross-sectional study determined the prevalence of loiasis among adult residents of forest-edge communities in Cross River State, South South Nigeria. A total of 280 participants were recruited through systematic sampling, and blood samples were collected between 10:00 and 14:00 hours to coincide with the diurnal periodicity of Loa loa microfilariae. Thick blood films were stained with Giemsa and examined for microfilarial presence and density. Structured interviews gathered data on forest entry frequency, occupational exposure, and awareness of Loa loa transmission. Microfilaraemia was detected in 12.5 percent of participants, predominantly among male farmers and hunters aged 30 to 55 years. Subconjunctival worm migration was self-reported in 18.2 percent of positive cases. The study notes that loiasis co-endemicity with onchocerciasis presents a complex challenge for mass drug administration using ivermectin due to serious adverse events in high-microfilaraemic individuals, necessitating pre-treatment screening. Keywords: Loa loa, loiasis, forest communities, Cross River State, mass drug administration.