Bovine anaplasmosis and babesiosis in the Lesser Antilles: risk assessment of an unstable epidemiologic situation.

A seroepidemiological survey on tick-borne diseases of ruminants was carried out on 11 islands of the Lesser Antilles from Grenada to St Martin. A total of 1,795 cattle were randomly sampled and sera tested for antibodies to anaplasmosis (Anaplasma marginale) and babesiosis (Babesia bovis and B bigemina) using a dot-ELISA test. Except for anaplasmosis, which was virtually absent from Guadeloupe, the seroprevalence of the 3 tick-borne diseases ranged from 18 to 71%. The epidemiologic situation was considered to be unstable in all of the study sites. The risk of clinical outbreaks was high in all the islands except for B bigemina in Montserrat and St Lucia and B bovis in St Lucia. The practical consequences in terms of tick eradication, tick control, and vaccination are discussed.