Molecular detection of bacterial and helminth pathogens in flea (Insecta: Siphonaptera) vectors: First report of D. caninum and C. burnetii in fleas from Türkiye.

Fleas are vectors of various pathogens affecting humans and animals. This study aimed to determine the presence and genetic diversity of Bartonella spp., Rickettsia spp., Coxiella burnetii, and Dipylidium caninum in fleas. Fleas were collected from domestic animals (sheep, goat, dog, and cat) in four districts (Artova, Sulusaray, Yesilyurt, and Central) of Tokat province. The flea species were identified morphologically and then separated according to their species; pools of one to five specimens were prepared for each species. Genomic DNA from the pooled samples was extracted and screened by PCRs for bacterial species, including C. burnetii, Bartonella spp., Rickettsia spp., and also helminths such as D. caninum. Positive samples were sequenced for pathogen characterization, and bioinformatics analysis was performed. Of the 345 fleas identified, 99 were Pulex irritans, 48 were Ctenocephalides canis, and 198 were Ctenocephalides felis. PCR results revealed that C. burneti in 12 pools (11 pools from P. irritans and one pool from C. felis) and D. caninum in three pools (one pool from C. felis, C. canis, and P. irritans) from 70 flea pools were detected. Additionally, none of the flea pools were positive for Rickettsia spp. and Bartonella spp. The sequencing results confirmed the presence of C. burnetii and D. caninum. The phylogenetic analyses revealed that our D. caninum isolates belonged to the "D. caninum canine genotype" group. Our C. burnetii isolates obtained from P. irritans and C. felis pools showed the highest identity (99.63 % and 99.81 %, respectively) with the isolate detected in a human blood sample from Brazil (JF970260). Medically and veterinary important fleas can carry multiple pathogens, and future research on flea-borne pathogens is vital for public health in the "One Health" concept.