Resistance of dogs to Rhipicephalus sanguineus and Haemaphysalis leachi leachi

It has been shown experimentally from three repeated infestations that dogs were unable to develop effective resistance against dog ticks: rhipicephalus sanguineus Latreille, 1806 and haemaphysalis leachi leachi Audouin, 1826. The number of successive engorged females recovered from dogs at the second and third infestations in both species were not significantly less (P>0.05) than the number recovered at the first infestation. There was also no significant difference in body weight, body dimensions (lengths and breadths) ofengorged females, feeding periods, pre-oviposition periods or egg weight. In-depth studies of host-tick vector interaction and examination of immunobiological parameters involved in order to develop strategies for better, cheaper and safer tick control in dogs as an alternative to the use of acaricides is suggested. key words: dogs, ticks, rhipicephalus sanguineus, haemaphysalis leachi leachi, resistance introduction rhipicephalus sanguineus Latreille, 1806 and haemaphysalis leachi leachi Audouin, 1826 are the most widespread ticks of dogs and known vectors of Babesia canis and B. gibsoni, the causative agents of canine babesiosis worldwide (Oduye and dIPeOLu, 1976; KuTTLer, 1988; BOBAde et al., 1989; CrAIg, 1990). rhipicephalus sanguineus is also well known as a vector of other pathogens of dogs, such as hepatozoon canis, ehrlichia canis (CrAIg, 1990), Coxiella burnetii (STePheN and AChyuThArAO, 1980), spotted group of rickettsiae (BeATI et al., 1996). They have also been reported to infest humans (SAdIq et al., 2001). The use of acaricides as dips, sprays or washes has been the main method of tick control in both food animals and dogs (TAyLOr, 2001). But because of the cost,environmental pollution, residues in food animals, development of resistance to the *Contact address: Johnson Olayide Adejinmi, dVM, Phd, department of Veterinary Microbiology and Parasitology, university of Ibadan, Ibadan, Nigeria, e-mail: [email protected]