Seroprevalence of Ehrlichia ruminantium (heartwater) in small ruminants in a pastoral production system in Narok district, Kenya

Abstract

A survey was undertaken on the prevalence of heartwater in Narok district, Kenya as a component of a broader study to establish constraints to livestock production in a Maasai pastoral production system. Serum samples were collected on a single occasion from 147 Red Maasai sheep and 149 Small East African goats aged 6 months to 3 years from three sites in the district. The sera were tested for antibodies to Ehrlichia ruminantium, by a MAP1 B ELISA. The sero-prevalence of E. ruminantium ranged from 62% to 82.5% in sheep, while in goats the range was 42.5% to 52%. Brain crush smears prepared from a dead sheep on the study site were positive for E. ruminantium organisms thus confirming the presence of the disease. The most prevalent tick species observed on the animals was Rhipicephallus appendiculatus with a mean tick count per animal of 3.98 to 5.67 while the mean tick count for Amblyomma variegatum, the vector of heartwater, was 0.015 to 0.12 per animal. The results of the study do suggest that the farmers need to adopt a regular tick control programme to prevent the susceptible animals from getting infected with heartwater.

Keywords: seroprevalence, survey, pastoral production system, sheep and goats, Ehrlichia ruminantium

Bulletin of Animal Health and Production in Africa Vol. 54(1) 2006: 23-33