Modelling the distribution of Rhipicephalus microplus and R. decoloratus in Zimbabwe

Abstract

Species distribution modelling is a very useful tool in vector management. Ticks are vectors of various pathogens which cause serious problems in livestock production in tropical countries. They have a high dispersal potential which is mainly facilitated by the movement of animals from one area to another. In light of the observed geographic expansion of Rhipicephalus microplus in Zimbabwe, we used species distribution modelling techniques to identify areas which may provide suitable habitats for the occurrence of this invasive tick species as well as the autochthonous Rhipicephalus decoloratus. Our results suggest that, despite the geographic expansion of R. microplus, climate will continue to be a limiting factor for the further expansion of this tick species. We expect its distribution to be restricted to the most favourable areas in the eastern and northern parts. The greater part of Zimbabwe is suitable for R. decoloratus, although in areas where R. microplus occurs, displacement of the former by the latter will be expected to occur. A heterogeneous climate, unregulated movement of cattle and episodic droughts are suggested to be possible factors for the continued existence of R. microplus and R. decoloratus in Zimbabwe and the partial displacement.

Identification, Distribution, and Habitat Suitability Models of Ixodid Tick Species in Cattle in Eastern Bhutan

“…This elevation range corresponds to the humid subtropical zone (600-1200 masl) in Bhutan, characterized by an annual mean temperature of 19.5 • C and an annual rainfall of 1200-2500 mm [1]. This agrees with a study from Zimbabwe, where elevation was found as the most influential factor for the geographic distribution of R. microplus and R. decoloratus [54]. In Bhutan, areas with higher elevation are characterized by colder temperatures and low rainfalls, and that might result in such areas to be less suitable habitats for R. microplus.…”

“…Rhipicephalus microplus was found more frequently in animals sampled in Pema Gatshel (98.2%) compared with those sampled in Trashigang (78.3%). Generally, this one-host tick species prefers warm and humid conditions [52], and temperature and rainfall are the most important climatic factors driving its geographic distribution [53,54]. Pema Gatshel, located at the warmer south, has the majority of its area dominated by subtropical climate with higher temperatures, abundant rainfall, and high relative humidity, while Trashigang is mainly characterized by a temperate climate with moderate temperature, rainfall, and relative humidity.…”

Cross border transhumance involvement in ticks and tick-borne pathogens dissemination and first evidence of Anaplasma centrale in Burkina Faso

“…Moreover, the low prevalences of B. bigemina at T2BF and of A. marginale at T0BF and T2BF could be attributed to the low infestation of cattle by R. decoloratus (Walker, 2003), one of their vector ticks. The occurrence of this species is known to be favoured by low rainfall (Sungirai et al, 2018) such as the beginning of rainy season at T1BN. Tick-borne pathogens identifications in cattle blood were confirmed by their presence in tick DNA samples.…”

Background on the control of the cattle tick R. (B.) microplus and the use of coumarin substances as an alternative

“…(B.) microplus is a species of Indo-Asian origin 18 that is widely distributed in tropical and subtropical regions between 32°N and 35°S latitude, in areas with an average annual rainfall of 750 to 1000 mm, a temperature range between 12°C and 24°C and altitudes from 250 to 1600 meters above sea level; 9,19 however, as a result of climate change, R. (B.)…”