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Introduction
It is well established that ticks and tick-borne diseases (TBDs) significantly impact domestic animal health and the livestock farming industry globally (Busch et al. 2014; De Castro 1997; Jonsson & Piper 2007). In Africa, it is estimated that animal losses because of high tick infestations and the control of TBDs such as babesiosis and anaplasmosis cost countries such as Kenya, Tanzania and Zimbabwe between $5 and $6 million per annum (McLeod & Kristjanson 1999). South Africa has a large commercial cattle farming industry and spends considerably more on TBDs per annum (approximately $21 million) (McLeod & Kristjanson 1999). There are two tick species that act as vectors of the causative agents of bovine babesiosis in South Africa: Rhipicephalus decoloratus (the African blue tick), which is endemic to Africa and transmits Babesia bigemina (African redwater) and R. microplus (the Asiatic blue tick), which is originally from southern Asia and acts as a vector for B. bigemina and B. bovis, the causative organism of Asiatic redwater in cattle. Rhipicehalus microplus is of greater concern in the cattle industry mainly because of the greater pathogenicity of B. bovis (De Vos, De Waal & Jackson 2004).
Rhipicephalus microplus, originally a parasite of bovid species in India and Indonesia (Barré & Uilenberg 2010; Labruna et al. 2009; Osterkamp et al. 1999), is presumed to have been introduced into Africa via Madagascar during the latter half of the 19th century (Hoogstraal 1956; Madder et al. 2011). The tick has subsequently spread across southern, eastern and western Africa and to date the affected countries include South Africa (Howard 1908; Tønnesen et al. 2004), Zimbabwe (Mason & Norval 1980), Swaziland (Weddernburn et al. 1991), Zambia (Berkvens et al. 1998), Ivory Coast and Benin (De Clercq et al. 2012; Madder et al. 2007), Tanzania (Lynen et al. 2008), Mozambique (Horak et al. 2009), Burkina Faso, Mali and Togo (Adakal et al. 2013) and Namibia (Nyangiwe et al. 2013b).
More specifically in South Africa, Howard (1908) was the first to record R. microplus among ticks collected at King William’s Town in the Eastern Cape province (ECP). Thereafter, Howell, Walker and Nevill (1978) recorded R. microplus in isolated pockets along the southern coast of the Western Cape province (WCP) in the districts...