Hard tick distribution and diversity in fresno county, california, and adjacent areas

This was the first survey in the central and southern San Joaquin Valley to identify the hard tick species present in this region. Hard tick distribution and diversity were evaluated in Fresno County and adjacent areas by (i) collection of ticks at three different elevation habitat sites and from veterinary sources, and (ii) subsequent phylogenetic comparison using fragments of 16S rDNA. A total of 178 ticks of 4 species were identified: Dermacentor occidentalis (n = 65), D. variabilis (n = 31), Ixodes pacificus (n = 2), and Rhipicephalus sanguineus (n = 80). Each species was restricted to a single habitat, but with detectable genetic variability within each species. R. sanguineus were only collected from dogs, I. pacificus were only collected from Kreyenhagen Peak, D. occidentalis were only collected from Coalinga Mineral Springs, and D. variabilis were only collected from China Creek Park. Further research is suggested to increase numbers of sampled sites, and to evaluate presence of tick borne pathogens.