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Loa loa
The African eye worm, a species of the family Onchocercidae (superfamily Filarioidea) that is indigenous to the western part of equatorial Africa, especially in the region of the Congo River, and is the causal agent of loiasis. Adult worms are white or gray-white, cylindric, and threadlike, the males averaging 25–35 × 0.3–0.4 mm (with a curved tail) and the females ranging from 50–60 × 0.4–0.6 mm; microfilariae are ensheathed, with nuclei extending to the tip of the tail. The life cycle is somewhat similar to that of Wuchereria species; humans are the only known definitive host, and parasites are transmitted by Chrysops flies (family Tabanidae); infective larvae from the latter require three years or more to mature in humans, and the adult forms may persist in a human host for as long as 17 years. | |
