Science abhors a surveillance vacuum: detection of ticks and tick-borne bacteria in southern New Mexico through passive surveillance

Abstract

Robust tick surveillance enhances diagnosis and prevention of tick-borne pathogens, yet surveillance efforts in the U.S. are highly uneven, resulting in large surveillance vacuums, one of which spans the state of New Mexico. As part of a larger effort to fill this vacuum, we conducted both active and passive tick sampling in New Mexico, focusing on the southern portion of the state. We conducted active tick sampling using dragging and CO2trapping at 45 sites across Hidalgo, Doña Ana, Otero, and Eddy counties periodically between June 2021 and August 2022. We also conducted opportunistic, passive tick sampling in 2021 and 2022 from animals harvested by hunters or captured or collected by researchers and animals housed in animal hospitals, shelters, and farms. All pools of ticks were screened forRickettsia rickettsii, R. parkeri, R. amblyommatis, Ehrlichia ewingii, andE. chaffeensis. Active sampling yielded no ticks. Passive sampling yielded 497 ticks comprisingCarios kelleyifrom pallid bats,Rhipicephalus sanguineusfrom dogs, mule deer, and Rocky Mountain elk,Otobius megninifrom dogs, cats, horses, and Coues deer,Dermacentor parumapertusfrom dogs and black-tailed jackrabbits,D. albipictusfrom domesticated cats, mule deer and Rocky Mountain elk, andDermacentor spp. from American black bear, Rocky Mountain elk, and mule deer. One pool ofD. parumapterusfrom a black-tailed jackrabbit in Luna County tested positive forR. parkeri, an agent of spotted fever rickettsiosis. Additionally, a spotted fever groupRickettsiawas detected in 6 of 7Carios kelleyipools. Two ticks showed morphological abnormalities; however, these samples did not test positive for any of the target pathogens, and the cause of the abnormalities is unknown. Passive surveillance yielded five identified species of ticks from three domestic and six wild mammal species. One tick pool from a black-tailed jackrabbit was found to harborRickettsia parkeri, and six pools ofCarios kelleyiticks, argasid ticks that have been reported to bite humans, were found to harbor a spotted fever groupRickettsia. Our findings update tick distributions and inform the public, medical, and veterinary communities of the potential tick-borne pathogens present in southern New Mexico.