Data from: Molecular and niche modeling approaches to identify potential amplifying hosts for an emerging tick-borne pathogen, Rickettsia rickettsii subsp. californica, the causative agent of Pacific Coast tick fever

Pacific Coast tick fever (PCTF) is a recently described zoonotic disease
in California caused by a spotted fever group rickettsia (SFGR),
Rickettsia rickettsii subsp. californica (formerly Rickettsia 364D) and
transmitted by the Pacific Coast tick, Dermacentor occidentalis. Like many
emerging vector-borne diseases, knowledge regarding the transmission
cycle, contribution from potential amplifying hosts, and geographic
distribution of R. rickettsii californica is limited. We paired molecular
analysis with comparative spatial niche modeling to identify vertebrate
hosts potentially involved the transmission cycle of this pathogen. We
identified R. rickettsii californica DNA in three mammal species
(Otospermophilus beecheyi, Lepus californicus, and Sylvilagus audubonii).
This is the first record of R. rickettsii californica detected in mammals
and may indicate potential amplifying hosts for this human pathogen.
Species niche modeling of uninfected and infected D. occidentalis
identified areas of high suitability along the coast and Sierra Nevada
foothills of California. These findings support the hypothesis that
amplifying host(s) may support higher infection prevalence in the infected
tick regions compared to other parts of the tick’s range. Potential host
species distribution models (SDM) were constructed from museum records and
niche overlap statistics were used to compare habitat suitability with R.
rickettsii californica-infected tick SDMs. We found higher than null
overlap of infected ticks with California ground squirrels (O. beecheyii)
and trending, but non-significant, overlap with two lagomorph species.
Pairing molecular and niche modeling may be a useful approach to identify
species that are involved in the maintenance of emerging tick-borne
zoonoses.