Flea-borne diseases affect cat health and the cat-human bond worldwide, and recently epidemics of re-emerging flea-borne diseases have been linked to cats. Of particular concern are two zoonotic bacteria listed as priority pathogens by the National Institutes of Health – Bartonella and Rickettsia species – that are the most common pathogens found in Ctenocephalides felis (the cat flea) in the United States. Free-roaming domestic cats are a particularly high-risk population for flea-borne pathogens, living at the interface between humans, other pets, wildlife, and the parasites that infest all these animals, and with limited access to veterinary care. In ticks and mosquitos, ecological factors like geography and climate, as well as vector-related factors like the microbial communities present in the vectors, are known to affect pathogen colonization and transmission. In contrast, little remains known about the risk factors associated with pathogen carriage in cat fleas.
To address this gap, we plan to survey fleas found on free roaming cats systematically sampled from all 48 continental states. This will help us determine the distribution of cat fleas across the country. We will then test the presence and abundance of pathogenic bacteria using 16S rRNA next-generation sequencing (16S-NGS), and evaluate associations between pathogen carriage and specific ecological, geographical, socioeconomic, and vector-related factors. This long-term study will allow us to systematically evaluate potential driving factors for pathogen colonization of these ubiquitous but understudied vectors, informing our ultimate quest to prevent transmission of potentially deadly pathogens to both pets and their people.