What happened after the introduction of Rhipicephalus microplus in West Africa: displacement and hybridisation on a large scale.
De Clercq, E.
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The cattle ticks Rhipicephalus microplus has been introduced in West Africa about a decade ago and since then, the tick has spread successfully in the region and is now recorded in five countries: Ivory Coast, Togo, Benin, Burkina Faso and Mali. Until now no detailed information was present on how R. microplus was behaving or if there was any interaction with local ticks of the same genus. It was observed however that the tick, although more adapted to warmer, humid conditions, has now spread to more northern areas were it also tends to displace the local ticks. In Benin, a detailed survey was executed to study the distribution of R. microplus after its initial introduction in one of the state farms in Kpinnou, in the south of the country. The results showed that R. microplus was widely distributed up to the northern departments but that identification of the blue ticks was sometimes cumbersome. The objective of this study was therefore to verify the morphology of the four blue ticks present in Benin, both morphologically and molecularly. For the morphological study ticks were identified using a stereo-microscope and SEM photos were taken of those ticks that showed intermediate characteristics For the molecular study, a random sample of what was seen as "pure" species were molecularly analyses using genomic (ITS2) and mitochondrial DNA 16S mDNA) and also a number of the hybrids. The preliminary results showed among the morphologically "pure" ticks, combined genetic profiles were found whereas the oppiste was also true: genetically pure species with combined morphological features. It was shown that morphological identification of ticks was not always correct and hybrid species might be overlooked or hybrids misidentified as pure species. Furthermore is was hypothesised that certain crosses do result in fertile offspring, questioning the importance of these hydrids especially concerning vectorial competence, acaricide resisistance and survival related to temperature and humidity. In conclusion it can be stated that R. microplus has successfully displaced the local blue ticks in Benin and possibly also other West African countries and has even hybridised with the local blue ticks, resulting in a population of ticks with unknown characteristics.
CitationMadder, M.; De Clercq, E.; Vanwambeke, S.; Jansen, F.; Sungirai, M.; Fannes, W. (2014). What happened after the introduction of Rhipicephalus microplus in West Africa: displacement and hybridisation on a large scale.. , VIII International Conference on Ticks and Tick-borne Pathogens (TTP-8),