Mansonelliasis

Abstract

Mansonelliasis is caused by one of three species of filarial parasite from the genus Mansonella: Mansonella ozzardi, M. perstans, or M. streptocerca. Mansonelliasis caused by M. streptocerca is thought to be limited to the equatorial rainforest areas of West and Central Africa. The more broadly distributed Mansonella perstans parasite is thought to be infecting around 114 million people in continental Africa alone and to also occur in certain parts of South America. Mansonella ozzardi is, however, the principal cause of mansonelliasis in the New World and the only known cause in Central America and the Caribbean. Mansonelliasis infections are typically diagnosed by the identification of microfilariae, which can be found in the blood (at all times of day) of those infected with M. perstans and M. ozzardi and in the skin of those infected with M. streptocerca. The three parasites can be distinguished from each other and the microfilariae of other filarial parasites by their morphological features or by PCR. There is, presently, no universally agreed symptom-set for the clinical diagnosis of mansonelliasis or guidelines for its treatment. Infections are often regarded as either mostly or completely asymptomatic and there have thus been few studies investigating its treatment. Presently, there are no large-scale internationally coordinated programs for mansonelliasis control. DEC, ivermectin, and doxycycline have all been shown to clear Mansonella microfilariae from some (though usually not all) infected individuals. Doxycycline treatment may be curative and seems to have the fewest side effects; it also, however, requires the longest treatment course and has only been tested on M. perstans.