This is a nematode that occurs in South America and the Caribbean (Haiti). The adult worms are 3 to 5 cm long by 70 to 150 m m wide and live in the body cavities, mesentery and subperitoneal tissues. The aperiodic microfilariae live in the blood and skin. They have no sheath, measure 200 m m long by 3 to 4 m m wide and have a long thin tail without nuclei. The microfilariae should be distinguished from tose causing onchocerciasis. The vectors are Culicoides and Simulium sp. The parasite also occurs in monkeys.

In general, the infection is well tolerated, but there may be symptoms of general malaise, pruritus, joint pain and arthritis. Diagnosis is made by blood examination (thick smear or Knott).

DEC is not effective. Ivermectin is probably active against the worm.