Dermacentor (Indocentor) auratus Supino 1897: Potential geographic range, and medical and veterinary significance

Dermacentor (Indocentor) auratus Supino, 1897 occurs in many regions of Southeast Asia and South Asia. In many regions of Southeast Asia and South Asia, targeted tick sampling and subsequent screening of collected D. auratus ticks have detected pathogenic bacteria and viruses in D. auratus. These disease-causing pathogens that have been detected in D. auratus include Anaplasma, Bartonella, Borrelia, Rickettsia (including spotted fever group rickettsiae), African swine fever virus, Lanjan virus, and Kyasanur forest disease virus. Although D. auratus predominantly infests wild pigs, this tick is also an occasional parasite of humans and other animals. Indeed, some 91 % of human otoacariasis cases in Sri Lanka were due to infestation by D. auratus. With the propensity of this tick to feed on multiple species of hosts, including humans, and the detection of pathogenic bacteria and viruses from this tick, D. auratus is a tick of medical, veterinary, and indeed zoonotic concern. The geographic range of this tick, however, is not well known. Therefore, in the present paper, we used the species distribution model, BIOCLIM, to project the potential geographic range of D. auratus, which may aid pathogen and tick-vector surveillance. We showed that the potential geographic range of D. auratus is far wider than the current geographic distribution of this tick, and that regions in Africa, and in North and South America seem to have suitable climates for D. auratus. Interestingly, in Southeast Asia, Borneo and Philippines also have suitable climates for D. auratus, but D. auratus has not been found in these regions yet despite the apparent close proximity of these regions to Mainland Southeast Asia, where D. auratus occurs. We thus hypothesize that the geographic distribution of D. auratus is largely dependent on the movement of wild pigs and whether or not these wild pigs are able to overcome dispersal barriers. We also review the potential pathogens and the diseases that may be associated with D. auratus and provide an updated host index for this tick.