Risk factors associated with Ehrlichia ruminantium and tick infestation amongst cattle in Guadeloupe, French West Indies.

Abstract

Ehrlichia ruminantium infection and infestations by two tick species, Amblyomma variegatum and Rhipicephalus microplus, are a major threat to the livestock sector in Guadeloupe. This study aimed to identify farming practices and livestock characteristics associated with the circulation of E. ruminantium antibodies in cattle (data already published) and tick infestations. Tick presence was assessed for 261 cattle from 73 farms across the three main islands of the Guadeloupe archipelago (Basse-Terre, Grande-Terre and Marie-Galante). The sampling methodology employed was designed to ensure representativeness of cattle farming in Guadeloupe. A questionnaire survey was implemented to gather information on herd management and husbandry practices. Risk factors were explored using multiple correspondence analysis (MCA) followed by a generalized linear model at the farm level, and finally a generalized linear mixed model at the cattle level. A total of 81% of the inspected cattle were infested with ticks, with a prevalence of 69% for A. variegatum and 47% for R. microplus. At the farm level, 96% of farms had infested animals, with 84% positive for A. variegatum and 73% for R. microplus. MCA revealed that non-traditional breeding system, with free-grazing animals, were associated with higher tick infestations and serological evidence of E. ruminantium exposure. The utilisation of green fodder also significantly influenced tick abundance and seropositivity. Differences in infestation patterns were observed between the three largest islands. The frequency of acaricide bathing and its interaction with acaricide alternation appeared to be significant factors in the mitigation of tick infestations in cattle.