Prevalence of heartwater in Guadeloupe (2024): stable endemicity and evidence of spread to Les Saintes

Heartwater is a tick-borne disease caused by Ehrlichia ruminantium and remains endemic in the Guadeloupe archipelago. While previous data from 1989 suggested a seroprevalence of 22 % in cattle, no updated figures were available for livestock, and certain islands such as Les Saintes were considered disease-free. This study aimed to update the sero-epidemiological status of heartwater in cattle and goats across Guadeloupe in 2024. Blood samples were collected from 261 cattle and 135 goats from all islands. Serological testing using the MAP1B ELISA was performed, and true seroprevalence was estimated using a simplified stochastic model that accounts for test sensitivity, specificity, and sample uncertainty. The mean cattle seroprevalence was estimated at 28 % (95 % CI [22-34 %]), with no significant differences between Basse-Terre, Grande-Terre, and Marie-Galante. Importantly, seropositive goats were identified on all major islands, including Les Saintes. Our findings suggest that heartwater remains endemically stable in Guadeloupe since the 1980s and reveal for the first time its serological presence in Les Saintes. These results emphasize the importance of strengthening regional surveillance systems, including veterinary reporting, serological monitoring, and coordinated efforts to prevent further spread across the Caribbean.