Cat fleas (Ctenocephalides felis clade ‘Sydney’) are dominant fleas on dogs and cats in New South Wales, Australia: Presence of flea-borne Rickettsia felis, Bartonella spp. but absence of Coxiella burnetii DNA

The cat flea (Ctenocephalides felis) is the most common flea species parasitising both domestic cats and dogs globally. Fleas are known vectors of zoonotic pathogens such as vector-borne Rickettsia spp. and Bartonella spp. and could theoretically transmit Coxiella burnetii, the causative agent of Q fever. A total of 107 fleas were collected from 21 cats and 14 dogs in veterinary clinics, a feline rescue organisation and a grooming salon in New South Wales, Australia, to undergo PCR detection of Bartonella spp., Rickettsia spp. and C. burnetii DNA. Morphological identification confirmed that the cat flea (C. felis) is the most common flea in New South Wales, Australia, with only a single stick fast flea, Echidnophaga gallinacea recorded. The examined fleas (n = 35) at the cox1 locus revealed five closely related C. felis haplotypes (inter-haplotype distance < 0.5%). Multiplex TaqMan qPCR targeting the gltA (Rickettsia spp.) and ssrA (Bartonella spp.) genes was positive in 22.9% (95% CI: 11.8–39.3%) and 11.4% (95% CI: 3.9–26.6%) of samples, respectively. None of the DNA isolated from fleas was positive on TaqMan qPCRs targeting the C. burnetii IS1111, Com1 and htpAB genes. Co-infection of C. felis with Bartonella henselae and Bartonella clarridgeiae was demonstrated using gltA and ssrA Illumina next-generation amplicon sequencing. These findings reinforce the importance of flea control on domestic dogs and cats to effectively control the transmission of Rickettsia felis and Bartonella spp. The flea, however, is unlikely to be a vector of C. burnetii between companion animals and humans.