Prevalence of gastrointestinal parasites in primate bushmeat and pets in Cameroon.

To document the prevalence of gastrointestinal parasites in Cameroonian monkeys and to assess the risk of transmission to humans, we sampled 125 primates belonging to 15 species, of which 78 had been captured for bushmeat in the wild, and 47 were pets kept in urban areas. Seven nematode species, one trematode, one cestode and three protozoa were detected. Eight different parasite species were found in Cercopithecus nictitans and six in C. neglectus, C. pogonias and Cercocebus agilis. Helminths were found in 77% of monkeys, and protozoa in 36%. Trichuris sp. and Entamoeba coli were the most frequent parasites, being found in 54% and 36% of animals, respectively. Helminths were more frequent in adults than in juveniles, while the prevalence of protozoa was not age-related. No significant gender difference was found. Bushmeat monkeys had a significantly higher prevalence of helminth infection than pets (92% versus 51%), whereas there was no significant difference in the prevalence of protozoa (32% versus 43%). Among helminth species, Strongyloides fulleborni was more prevalent in bushmeat monkeys than in pets (55% versus 15%), as were Ancylostoma spp. (62% versus 9%). As these parasites are transmitted transcutaneously by infectious larva, they have a high potential for transmission to humans, during butchering. One pet monkey kept in an urban household in Yaoundé was infected by Schistosoma mansoni. The potential public health implications of these findings are discussed.

A study of onchocerciasis with severe skin and eye lesions in a hyperendemic zone in the forest of southwestern Cameroon: clinical, parasitologic, and entomologic findings.

Prior to the initiation of an onchocerciasis control program based on the mass administration of ivermectin in the rain forest of southwestern Cameroon, a preliminary baseline study of the area was conducted. The results of this study showed that onchocerciasis was hyperendemic in the area. Skin symptoms and signs were observed including pruritus (67.4% of the population examined), onchocerca nodules (51.6%), skin depigmentation (18.5%), and hanging groins (5.7%). Except for pruritus, the prevalence of these symptoms increased with age. Of the eyes examined, 44.9% had microfilariae in the anterior chamber, 33.5% had choroidoretinitis, 28.0% had punctate keratitis, 8.3% had papillary abnormalities, and 3.6% had sclerosing keratitis. Vision in 10.5% of the eyes examined was classified as blind or very poor (visual acuity = 0-0.10), in 15.7% as poor (visual acuity = 0.11-0.39), and in 73.8% as good (visual acuity = 0.4-1.00). Unlike previous reports that have linked serious ocular damage mainly to savanna onchocerciasis, the present study showed that forest onchocerciasis also caused significant ocular pathology, including blindness. Parasitologically, positive skin snips were recorded for 92.7% of the persons examined, with both sexes being equally infected. The parasite load, expressed as the geometric mean number of microfilariae per skin snip, was 53.6, and was much higher in males than in females. The flv vector, Simulium squamosum, had a high infection rate of 7.5% infective females in Bakumba and 6.8% infective females in Ngbandi, the two fly-catching points. The transmission potential was 266 infective larvae per person per month in Bakumba and 189 in Ngbandi.

A community-based trial of ivermectin for onchocerciasis control in the forest of southwestern Cameroon: clinical and parasitologic findings after three treatments.

In the onchocerciasis-endemic rain forest area of the Rumpi Hills in southwestern Cameroon, a community-based trial of ivermectin, given either once or twice a year over a three-year period (1988-1991), confirmed that the drug is a potent microfilaricide. The side effects recorded following the first treatment were edema, fever, pruritus, generalized body pains and lymphadenitis. Following subsequent treatments, the same adverse reactions were recorded, but these were generally milder when compared with those of the first treatment. The prevalence of skin microfilaria (mf) was more reduced in zone two, in which treatment was given every six months (76.9% reduction at the end of one year) than in the zone one, in which treatment was given once a year (7.4% reduction). In both zones, the impact of the drug in reducing the intensity of infection was more significant than that for prevalence. Besides pruritus, other skin symptoms were not significantly modified by ivermectin treatment. Ivermectin reduced the prevalence of ocular mf as well as the mf load of the anterior chamber of the eye, resulting in improvement of certain eye lesions such as punctate keratitis, anterior uveitis, and papillary anomalies. There was also some improvement in visual acuity. The level of participation of the village populations was somewhat low, ranging from 52% to 66%, despite excitement over the drug's additional benefit of expelling intestinal round worms.