1%. He was then treated with mebendazole (100 mg twice a day, for 14 days), and at the end of his treatment, his visual impairment was the only symptom remaining. After a week, with no further treatment, his vision improved and acuity was increased to 8/10 in the left eye. While ocular symptoms occur quite frequently in symptomatic M. perstans infection, intraocular localization had not been described prior to this study. This case also is an example of the difficulty of treating mansonelliasis, and shows that combined drug regimens can be more effective than treatment using a single drug. Other relevant clinical information M. perstans might potentially interfere with the host's regulatory mechanisms and influence the outcome of other infections, such as malaria, tuberculosis and HIV, which often thrive in similar environments. Recent research has also focused on coinfection of M. perstans and other filarial parasites. A study examining the epidemiology of Loa loa, Onchocerca volvulus, and M. perstans in the rain forest villages of Cameroon found a high prevalence of coinfection with O. voluvulus and M. perstans. It also found a low prevalence of L. loa and O. voluvulus coinfection, as well as low prevalence of L. loa and M. perstans coinfection. Coinfection also has significant implications for treatment, because efficacious drugs for M. perstans are different from those for most filarial infections. Another study evaluated the effectiveness of ivermectin and albendazole in M. perstans and Wuchereria bancrofti coinfection in a filarial endemic region of Mali, finding that M. perstans infection did not have a significant effect on the treatment of W. bancrofti. Other studies have evaluated the efficacy of other treatments on co-infection with other filarial parasites and M. perstans. Transmission M. perstans is transmitted by the bite of species of Culicoides midges. Only the female midges take blood meals, because the blood is needed for the maturation of eggs within the female. Reservoir Humans are the only known reservoir for M. perstans. No animal reservoirs for M. perstans occur as there are for Mansonella streptocerca. Vector Various species of Culicoides can be found worldwide, and in some areas, their high numbers make them a biting nuisance to humans and domestic animals. Culicoides species are stout flies with short vertical probosces and wings folded scissor-like over their abdomens at rest. They generally measure 1–4 mm in length. The wings of most species have a pattern of light and