Mansonella ozzardi is endemic to many tropical locations throughout the New World. Locations include various parts of Mexico, Panama, Brazil, Colombia, Argentina, as well as many islands in the Caribbean.
M. ozzardi consists of two biological forms. One is transmitted by black flies of the Simulium family and is mainly found in the Amazon and parts of the South American mainland. The other form is transmitted by midges of the Culicoides family and is endemic to beach areas in the Caribbean where these pests are common. Once in the human host the larvae move into the peritoneal cavities. The adults then mate and produce unsheathed microfilariae about 207-232 x 3-4 micrometers in size. The microfilaria closely resemble those of M. perstans except they have a sharp tail. They are nonperiodic like their vectors and can be found in the blood and skin at all times.