The relationship between coccidial and helminth infections in sheep and goats in Kenya

Studies on prevalence of coccidian oocysts and their infection levels (oocysts g-1, OPG) were carried out among various age groups of sheep and goats from different geographical locations in Kenya. Prevalent species of Eimeria were identified and levels of infection with strongyle eggs (eggs g-1, EPG) examined. A significant difference was found in the EPG levels between various farms but not in the OPG levels; this was attributed to the relative susceptibility of various preparasitic stages of helminths to adverse climatic conditions, especially desiccation, compared with coccidian oocysts. There was a negative correlation between OPG levels and the age of animals as a result of acquired immunity. Between OPG and EPG values there was a positive correlation which is in tandem with the role of contamination in the acquisition of both types of infection. Sheep were found to shed significantly more oocysts and helminth eggs than goats; this could be related to the differences in their mode of feeding, i.e. grazing and browsing respectively. Young age (under 1 year) and confinement were found to contribute to high prevalence of oocysts in faecal samples. In sheep, a total of ten species of Eimeria were identified, the most prevalent being E. ovina (43%) and E. ovinoidalis (16.5%). In goat samples, eight species were identified, the commonest being E. arloingi (37.5%) and E. ninakohlyakimovae (35.2%).