Domestic fleas infest scores of wild mammal species

A study led by the University of Queensland, Australia, has found that fleas from domestic pets are infesting numerous wildlife species globally, affecting animals on every continent except Antarctica.

The study looked at the distribution of two species of fleas – Ctenocephalides felis and C. canis – which favour cats and dogs, respectively, as hosts.

Led by Nicholas Clark and published in the journal Parasites & Vectors, the research findings illuminated the risk and magnitude of the transmission of pathogens carried by the insects from domestic to wild animals, and the potential hazards of continued, unchecked infections.

The authors built a comprehensive worldwide database to gauge the extent of interactions between the two flea species and wild hosts. They used statistical modelling to determine the risk factors of wildlife infestations, and they performed genetic analyses to ascertain whether fleas preferentially infect wild hosts closely related to their domestic ones.

The dataset revealed that the risk of flea infestation and the subsequent spread of diseases from domestic to wild animals was widespread in scale and geographical range. The main predictor of flea conveyance was the proximity between human and natural habitats.

Of greater concern was the finding that fleas could also be transferred to wild animals if they came in contact with feral animals such rats, foxes and rabbits. Interestingly, the evolutionary and genetic analyses indicated that the dog flea was more selective, infesting around 31 different wild mammalian species, whereas the cat flea was found on a broad variety of species — more than 130.

The researchers hope that the findings will show there is an urgent need for limiting contact between wild and domestic animals to stem the spread of dangerous infections and maintain the health of wild populations.