Cameroon: A republic in central Africa lying east of CHAD and the CENTRAL AFRICAN REPUBLIC and west of NIGERIA. The capital is Yaounde.Africa, Central: The geographical area of Africa comprising CAMEROON; CENTRAL AFRICAN REPUBLIC; CHAD; CONGO; EQUATORIAL GUINEA; GABON; and DEMOCRATIC REPUBLIC OF THE CONGO.Ape Diseases: Diseases of chimpanzees, gorillas, and orangutans.Onchocerciasis: Infection with nematodes of the genus ONCHOCERCA. Characteristics include the presence of firm subcutaneous nodules filled with adult worms, PRURITUS, and ocular lesions.Chad: A republic in central Africa, east of NIGER, west of SUDAN and south of LIBYA. Its capital is N'Djamena.Africa, Western: The geographical area of Africa comprising BENIN; BURKINA FASO; COTE D'IVOIRE; GAMBIA; GHANA; GUINEA; GUINEA-BISSAU; LIBERIA; MALI; MAURITANIA; NIGER; NIGERIA; SENEGAL; SIERRA LEONE; and TOGO.Cercocebus: A genus of the subfamily CERCOPITHECINAE inhabiting the African forests. They are also known as mangabeys.Ivermectin: A mixture of mostly avermectin H2B1a (RN 71827-03-7) with some avermectin H2B1b (RN 70209-81-3), which are macrolides from STREPTOMYCES avermitilis. It binds glutamate-gated chloride channel to cause increased permeability and hyperpolarization of nerve and muscle cells. It also interacts with other CHLORIDE CHANNELS. It is a broad spectrum antiparasitic that is active against microfilariae of ONCHOCERCA VOLVULUS but not the adult form.Primate T-lymphotropic virus 3: A species of DELTARETROVIRUS that includes the strains SIMIAN T-LYMPHOTROPIC VIRUS 3 and HUMAN T-LYMPHOTROPIC VIRUS 3.Loa: A genus of parasitic nematodes found throughout the rain-forest areas of the Sudan and the basin of the Congo. L. loa inhabits the subcutaneous tissues, which it traverses freely.Gorilla gorilla: This single species of Gorilla, which is a member of the HOMINIDAE family, is the largest and most powerful of the PRIMATES. It is distributed in isolated scattered populations throughout forests of equatorial Africa.Loiasis: A parasitic infection caused by the nematode Loa loa. The vector in the transmission of this infection is the horsefly (Tabanus) or the deerfly or mango fly (Chrysops). The larvae may be seen just beneath the skin or passing through the conjunctiva. Eye lesions are not uncommon. The disease is generally mild and painless.