MSD Animal Health and the University of Bristol have published the results of their 'Big Flea Project' research1, which highlights the ongoing need for flea control, and a need to educate owners about the pathogenic risks fleas present.

For the research, 326 recruited veterinary practices examined 812 cats and 662 dogs using a standardised flea inspection protocol in April and June 2018.

Fleas were collected, the species identified, and pooled flea samples from each host were analysed for the presence of pathogens using PCR and sequence analysis.

Overall, fleas were found on 28.1% of cats and 14.4% of dogs.

Unsurprisingly, over 90% of the fleas on both cats and dogs were our dear old friends, Ctenocephalides felis. 

The PCR results found that at least 14% of the samples were positive for at least one pathogen, and 11.3% were positive for Bartonella spp (35 from cats, 4 from dogs), a pathogen which was identified as a risk to veterinary professionals and others with direct animal contact in a 2010 research paper2.

Entomologist Professor Richard Wall from the University of Bristol said: "Fleas are the most clinically important ectoparasites of dogs and cats worldwide.

"Rising levels of pet ownership, climate change and globalisation are increasing the importance of a detailed understanding of the endemicity and prevalence of flea-borne pathogens. This requires continued surveillance to detect change.

"The results have shown the high numbers of cats and dogs that still carry fleas and the relatively high prevalence of Bartonella spp found in the samples provided, which is of significant concern for the health of the pet, pet owner and veterinary practice staff."

Nicola Barclay, Senior Product Manager at MSD Animal Health said: "The Big Flea Project results demonstrate the ongoing need for pet owners to understand the importance of flea prevention, particularly with the implications of infestation for human and animal health.

"It’s particularly important at this time of the year as the weather is getting warmer and infestation is more likely to occur.

"Our national launch today has been designed to raise awareness amongst pet owners and encourage them to seek advice from the veterinary practice.

"Building awareness of the risks of fleas to practices and pet owners is also at the forefront of our ongoing campaign."


  1. Abdullah, S., Helps, C., Tasker, S., Newbury, H. and Wall, R. (2019), Pathogens in fleas collected from cats and dogs: distribution and prevalence in the UK. Parasites and Vectors, 12:71. doi:10.1186/s13071-019-3326-x
  2. Breitschwerdt, E. B., Maggi, R. G., Chomel, B. B. and Lappin, M. R. (2010), Bartonellosis: an emerging infectious disease of zoonotic importance to animals and human beings. Journal of Veterinary Emergency and Critical Care, 20: 8-30. doi:10.1111/j.1476-4431.2009.00496.x

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