Study of the epidemiology and impact of ticks and tick-borne diseases in different cattle breeds in the South of the Ivory Coast.

Ticks are regarded as the ectoparasites that have the biggest impact on livestock, especially cattle production throughout the world. They are not only vectors for a wide spectrum of pathogenic organisms and therefore transmit various diseases, but the tick infestation itself can also affect the livestock and add to the economical loss. Animals can suffer from a considerable loss of blood due to the feeding and some of the tick species can even cause paralyses or toxicosis while feeding.
Although tick-borne diseases are a global problem, they are nevertheless most numerous and exert their greatest impact on livestock in the Tropical and Subtropical regions.
Our study did concentrate on the major tick-borne disease, i.e. Cowdriosis, Anaplasmosis, Theileriosis and Babesiosis to be found in bovines in the South of the Ivory Coast. These diseases are known to exist in the Ivory Coast, however the real prevalence of the different tick-borne pathogens and their distribution in the country were not known at the study start.
The Southern Zone is gaining importance for cattle production. In many of the farms we observe a change in the cattle production. In order to increase the meat and milk production, farmers started crossbreeding by artificial insemination with sperm of exotic breeds. However, the main health impediments to efficient livestock production in the Ivory Coast are still the tick-borne diseases. The phenomenon is emphasized in the new crossbreeds, which will be more sensible to the problem.
Before any improvement can be made for the cattle production, baseline data were needed. The present study aimed on one hand to identify the different tick species present on cattle in the Southern region and on the other hand to assess the prevalence and distribution of the divers pathogens in cattle and ticks causing the various tick-borne diseases using molecular tools such as PCR and Reverse line blot assays (RLB). The results will be analysed and used to elaborate an efficient tick-control strategy.
As in other West African countries, Amblyomma variegatum was found to be the most frequent tick species. Further, Boophilus decoloratus, Boophilus geigyi, Boophilus annulatus and Rhipicephalus lunulatus could be found on cattle. The blood analyses confirmed the presence of the following pathogens Theileria mutans, Theileria velifera, Babesia bigemina, Babesia bovis, Anaplasma marginale and Ehrlichia sp. In contrast, we were not able to detect any samples reacting positive for Ehrlichia ruminantium, Anaplasma centrale nor Ehrlichia bovis. A detailled analysis of the prevalence of the pathogens is presently carried out.
A resistance to some of the acaricides widely used for the common treatment in the Ivory Coast has been noticed during our study. Currently, there is a lack of knowledge and more research is needed to document this resistance problem. Therefore, to finalise a good and an efficient tick control program, we suggest to continue the project and to emphasize on the occurrence of possible tick resistance to the divers acaricides.

The study was carried out in close collaboration with Dr Louise Achi (Laboratoire Central Vétérinaire de Bingerville, LANADA) in the region around Abidjan.

Contacts:

Christine Rühle, University of Neuchâtel, Institute of Zoology, Neuchâtel, Switzerland.
E-mail: christine.ruhle@unine.ch

Dr Louise Yaba Atse-Achi, LANADA, Laboratoire Central Vétérinaire de Bingerville, Bingerville, Côte d’Ivoire.
E-mail : louise.achi@csrs.ci