High-throughput screening reveals frequent Bartonella DNA detection in bat ectoparasites from Armenia: Associations with ectoparasite taxon and life stage

Bats and their ectoparasites form complex host-vector systems capable of maintaining diverse bacterial pathogens, yet these interactions remain poorly characterized in the Caucasus. We conducted the first high-throughput molecular survey of bacterial and protozoan pathogens in bat ectoparasites in Armenia. A total of 450 ectoparasites (mites and ticks) collected from 72 bats were pooled into 189 samples and screened using microfluidic real-time PCR targeting 43 bacterial and protozoan pathogens. The ectoparasite community was dominated by Spinturnix myoti and S. psi , which showed structured but overlapping associations with Myotis blythii and Miniopterus pallidus . Bartonella DNA was detected in 34.4% of pools, whereas Rickettsia spp. was rare (1.1%). At the bat level, 62.5% of individuals carried Bartonella -positive ectoparasites. Bartonella detection frequency in pools varied significantly among ectoparasite taxa, with Spinturnix mites showing approximately higher odds of Bartonella DNA detection than Macronyssus granulosus . Life stage was a strong predictor of DNA detection, with adult mites far more frequently positive than immature stages. Host species, region, and sex did not significantly influence pool positivity. These findings highlight the potentially relevant association of spinturnicid mites in Bartonella circulation within Armenian bat colonies requiring further study and provide essential baseline data for understanding the ecology of vector-borne bacteria in the Transcaucasia.