Infection with Mansonella perstans Nematodes in Buruli Ulcer Patients, Ghana

摘要

Buruli ulcer, caused by Mycobacterium ulcerans, is a neglected tropical disease common in rural parts of West Africa. Infection with M. ulcerans causes disfiguring skin ulcers, mainly in children. The disease is highly focal, and in Ghana, cases are reported mainly from the humid and tropical southern regions, including Ashanti and Greater Accra (1). Recent studies suggest that aquatic invertebrates serve as a reservoir for M. ulcerans, although complete transmission pathways remain unknown (2,3). Aquatic insects infected with M. ulcerans can establish infection in mice by biting (4), but it is not clear that this is the cause of human infection (5). In southeastern Australia, evidence has been found linking infected mosquitoes with human cases (6,7), but proof of transmission is lacking. Residents of regions in which Buruli ulcer is endemic are frequently exposed to parasitic infections such as filariasis. In Ghana, lymphatic filariasis caused by Wuchereria bancrofti nematodes is found in several regions to which Buruli ulcer is endemic, such as the Upper Denkyira District in the central region of Ghana, but its prevalence is unknown (8). The filarial nematode Mansonella perstans is endemic to countries in central and western Africa; its distribution overlaps that of other filarial nematodes W. bancrofti, Loa loa, and Onchocerca volvulus (9). Infective M. perstans larvae are transmitted through the bite of Culicoides midges (Diptera: Ceratopogonidae); the larvae develop over the course of months into adult worms that reside in serous cavities, particularly in the abdomen. M. perstans infection is not associated with a specific set of clinical signs and symptoms, but those attributed to this infection include acute swelling in the forearms, hands, and face that recedes in a few days and often recurs; itching with or without rash; arthralgia; and eosinophilia (9).