Heartwater in Guadeloupe and in the Caribbean

A sero-epidemiological survey for heartwater was organized in 1992 in the Lesser Antilles, from Grenada to Saint Martin. Blood from about one percent of the ruminant livestock of the islands was randomly sampled and the sera were tested with an indirect ELISA. The percentage of positive sera was found to be 30% in Guadeloupe, 25% in Antigua, 2.2% in St.Martin, 1.3% in St. Kitts & Nevis, 3.8% in Montserrat, 1.7% in Dominica, 1.5% in St.Lucia, 1.5% in St.Vincent, 3.5% in Barbados, 2.9% in Grenada and 7% in Martinique. Ruminants from Guadeloupe and Antigua are known to be infected with heartwater. The low percentage of positive sera and the absence of clinical cases in the other islands strongly suggest that positive sera in these islands are probably due to non-specific cross reactions between Cowdria and other micro-organisms (possibly Ehrlichia) which remain to be isolated. In particular, the high percentages of positive sheep sera in Martinique (15%) and Montserrat (11%) should be further investigated.