A comprehensive survey of the prevalence and spatial distribution of ticks infesting cattle in different agro-ecological zones of Cameroon

BACKGROUND: Ticks and tick-borne diseases are a major impediment to livestock production worldwide. Cattle trade and transnational transhumance create risks for the spread of ticks and tick-borne diseases and threaten cattle production in the absence of an effective tick control program. Few studies have been undertaken on cattle ticks in the Central African region; therefore, the need to assess the occurrence and the spatial distribution of tick vectors with the aim of establishing a baseline for monitoring future spread of tick borne-diseases in the region is urgent. RESULTS: A total of 7091 ixodid ticks were collected during a countrywide cross-sectional field survey and identified using morphological criteria. Of these, 4210 (59.4%) ticks were Amblyomma variegatum, 1112 (15.6%) Rhipicephalus (Boophilus) microplus, 708 (10.0%) Rhipicephalus (Boophilus) decoloratus, 28 (0.4%) Rhipicephalus (Boophilus) annulatus, 210 (3.0%) Hyalomma rufipes, 768 (10.8%) Hyalomma truncatum, and 19 (0.3%) Rhipicephalus sanguineus. Three ticks of the genus Hyalomma spp. and 33 of the genus Rhipicephalus spp. were not identified to the species level. Cytochrome c oxidase subunit 1 (cox1) gene sequencing supported the data from morphological examination and led to identification of three additional species, namely Hyalomma dromedarii, Rhipicephalus sulcatus and Rhipicephalus pusillus. The finding of the invasive tick species R. microplus in such large numbers and the apparent displacement of the indigenous R. decoloratus is highly significant since R. microplus is a highly efficient vector of Babesia bovis. CONCLUSIONS: This study reports the occurrence and current geographical distribution of important tick vectors associated with cattle in Cameroon. It appears that R. microplus is now well established and may be displacing native Rhipicephalus (Boophilus) species, such as R. decoloratus. This calls for an urgent response to safeguard the livestock sector in western central Africa.