Les tiques des ruminants dans les petites Antilles : Biologie, importance économique, principes de lutte

Abstract

Two species of tropical ticks, Boophilus microplus, originating from Asia and Amblyomma variegatum originating from Africa, parasitize the ruminants of the West Indies and in particular the French Antilles (Guadeloupe and Martinique). They are the vectors of various diseases including babesiosis and anaplasmosis for B. microplus and benign theileriosis and cowdriosis for A. variegatum. In addition, A. variegatum is associated with clinically severe and often fatal forms of Dermatophus congolensis disease (cutaneous Streptothricosis). The majority of the cattle on Guadeloupe are the Creole type, which are highly resistant to these diseases. The goats on Guadeloupe, however, suffer heavily from cowdriosis. The overall economic damage due to ticks on Guadeloupe is estimated to be 13.8 MF. While B. microplus seems to cover the full extent of its potential geographic range including the West Indies and the continent, A. variegatum, which is the more pathogenic species, is only found in the lesser Antilles and Porto Rico. Around the middle of the century it was only found on 4 islands, but over the last 25 years it has infested 14 new islands. It seems highly likely that cattle egrets are to blame for the recent acceleration in its propagation. These egrets came to the Lesser Antilles from Africa near the end of the 50's, and are currently found throughout the Caribbean. The A. variegatum infestation now threatens the American continent and the Greater Antilles. Despite its great capacity for regional distribution via its hosts, this tick has a limited productivity and is therefore less able to install itself and form colonies than B. microplus. It is therefore relatively easy to eradicate a colony if proper counter measures are taken as soon as it is detected. Wherever such a colony is established, taking rigorous measures that interrupt the development cycle should destroy the population. In addition, A. variegatum does not seem to be resistant to acaricides and seems to be relatively specific to domestic animals of a large size during its adult stage. These aspects favour the development of a defensive strategy which would eradicate these ticks by regularly applying acaricides on their domestic hosts.