Dermal microfilariae recovered form specimens obtained from umbilical and cervical sites of cattle infected with adult Onchocerca gutturosa alone or with adults of O gutturosa and O lienalis were measured and compared with uterine microfilariae obtained directly from gravid female worms of each species. Uterine microfilariae of O gutturosa were longer than dermal microfilariae obtained from cattle harboring only adults of O gutturosa. Dermal microfilariae were recovered from umbilical and cervical sites in these cattle. Those found at the cervical site had lengths equal to or greater than lengths of microfilariae recovered from the umbilical site. There was a significant (P less than 0.0001) shift in length across populations of microfilariae of O gutturosa from various sites in its bovine host, with a progressive decrease in length between microfilariae recovered from the worm's uterus, microfilariae from the cervical dermis, and microfilariae from the umbilical dermis, respectively. A similar direct comparison was not possible for microfilariae of O lienalis, because none of the cattle was infected with only adult worms of this species. In an indirect comparison, microfilariae of O lienalis were identified at the umbilicus, but their presence in the cervical region could not be determined unequivocally because of confounding of microfilariae length by concurrent infection with O gutturosa. Uterine microfilariae from O lienalis were longer than uterine microfilariae of O gutterosa, although a degree of overlap in the range of measurements existed between species.

Most studies on Simulum damnosum in Nigeria has focused mainly on the problem of onchocerciasis from the ecological standpoint. However, this study is aimed at viewing it from the human angle, with focus placed on the ignorance of the rural dwellers about the influences of their environment on the increasing incidences of onchocerciasis in their population. The premise is that, as the government and the scientists are working towards finding a lasting solution to the epidemic, the rural dwellers need to wake up to the realities of their own destiny. They need to come out and collaborate with other good efforts to form a strong united force that will rid their society of this menace. A study on the level of ignorance was carried out. It is assumed that their ignorance has kept the villagers relatively inactive and passive about freeing themselves. A descriptive method was used for this research and about 450 villagers were randomly selected and verbally interviewed. A questionnaire was designed and used as the instrument of the research. The research was carried out in two different villages of Asejire and Asepari. Findings were encouraging. Some of the villagers did not know about the existence of the disease even when some of their close relatives showed the symptoms. This high level of ignorance shows that it will be difficult to attain any cooperation from them in any attempt to make their environment unfavourable for the vector.

gastrointestinal parasites, horses, anthelmintic efficacy of ivermectin, adverse local or systemic reactions not observed