Serological survey of heartwater relative to the distribution of the vector Amblyomma variegatum and other tick species in north Cameroon.

A study was carried out on the spatial and temporal distribution of Amblyomma variegatum and other ticks infesting sheep and goats in northern Cameroon. A serological survey of heartwater (cowdriosis) using a competitive ELISA was concurrently carried out in the same flocks. A. variegatum was found to be the most predominant species accounting for 48.3% of all the ticks collected. Other species identified included Rhipicephalus sulcatus, R. lunulatus, R. turanicus, Boophilus decoloratus, B. annulatus, Hyalomma nitidum and H. truncatum. Tick control was found to be necessary between June and December in the North and in the southern part of the Far North Provinces with annual rainfall average of 800 mm and above. Heartwater serology indicated that the disease appears to be endemic with a mean prevalence of antibodies to Cowdria ruminantium of 61-67%. Antibody prevalence was highly associated with the presence of A. variegatum (P < 0.001). Studies of the susceptibility of animals from Amblyomma-free areas to heartwater through natural exposure to the vector are envisaged.