Molecular survey of tick-borne pathogens in Otobius megnini from Central Mexico with special emphasis on Bartonella detection

Soft ticks (Argasidae) remain among the least studied hematophagous ectoparasites. One of these species, Otobius megnini , the spiny ear tick, is a widely distributed, likely Nearctic-origin species whose global spread has been facilitated by the movement of cattle and horses—its primary hosts. Despite its generalist habits and ability to parasitize a wide range of mammals, including livestock and companion animals from the orders Artiodactyla and Carnivora, its role as a potential vector of pathogens remains poorly understood. Previous studies have linked O. megnini to otitis and tissue damage during its larval and nymphal stages, and it is suspected of contributing to the maintenance of Coxiella burnetii and Anaplasma sp., the causative agents of Q fever and anaplasmosis. This study aimed to detect bacterial and protozoan pathogens in O. megnini collected January 2019 and July 2023 from dogs ( Canis lupus familiaris ), cattle ( Bos taurus ), and the environment across three central Mexican states (Mexico State, Guanajuato, and Hidalgo). A total of 690 specimens (42 females, 13 males, 624 nymphs, and 11 larvae) from 50 hosts of two different species, as well as from the environment in 12 localities in the states of Mexico, Guanajuato, and Hidalgo, were analyzed using conventional PCR and sequencing to detect Anaplasma , Bartonella , Coxiella , Ehrlichia , Rickettsia , and Babesia . Bartonella bovis DNA was detected in 10 engorged nymphs recovered from cattle in the State of Mexico; no additional pathogens were found. This represents the first molecular detection of Bartonella in O. megnini worldwide and particularly in Mexico. Further studies are needed to assess its implications for animal and human health. • Otobius megnini remains a poorly studied soft tick despite its wide distribution and veterinary relevance. • A total of 690 O. megnini specimens from dogs, cattle, and the environment were screened in central Mexico. • Molecular analyses targeted Anaplasma , Bartonella , Coxiella , Ehrlichia , Rickettsia , and Babesia . • Bartonella bovis DNA was detected in 10 engorged nymphs collected from cattle. • This study reports the first worldwide detection of Bartonella in O. megnini , highlighting potential One Health implications.