Several ectoparasites on domestic dogs are considered important to public health,
particularly fleas, ticks and lice can also transmit pathogens to humans and domestic animals. In
this study, a survey of ectoparasite infestation on domestic dogs from eight sub-districts of
Mueang Chiang Rai District, Chiang Rai Province, Thailand was performed between June and
October 2011. A total of 1,498 ectoparasites belong to three species including Rhipicephalus
sanguineus (hard tick: 64.55%), Ctenocephalides felis orientis (flea: 33.85%), and Heterodoxus
spiniger (chewing lice: 1.60%). Prevalence of ectoparasite infestation on domestic dogs was
91.25% with the highest prevalence found in Mae Khao Tom and Huai Sak areas (100%) and the
lowest in Wiang area (80%). The number of dogs infested were 81.25% (n = 130/146) for
Rhipicephalus sanguineus, 53.13% (n = 85/146) for Ctenocephalides felis orientis, and 2.50% (n
= 4/146) for Heterodoxus spiniger. The Mean density of ectoparasites per host was 10.26% with
the majority being Rhipicephalus sanguineus (7.44%) followed by Heterodoxus spiniger (6.00)
and Ctenocephalides felis orientis (5.96). The results demonstrated that the mixed infestations
of Rhipicephalus sanguineus and Ctenocephalides felis orientis (46.57%, n=68) were mostly
found in domestic dogs. Both species are the major ectoparasites vector of pathogens
transmission from domestic dogs to human and other animals in high prevalence areas.