As the ambient temperature cools, our rodent brethren may seek to join us indoors in our warm homes.  Here are some of the more common concerns regarding your pets coming into contact with these pesky squatters:

Intestinal parasites such as hookworms and roundworms

Our pets can contract intestinal parasites from rodents by having direct contact with their sometimes interesting (to our pets) feces (i.e. ingestion of at least a microscopic amount of the rodent’s stool) and through hunting.  Heartworm prevention usually keeps intestinal parasites under control as most of these medications also contain an ingredient that treats hookworms and roundworms.  Since most of the pets in Seattle do not receive heartworm prevention (pets who have not left the Seattle area are extremely unlikely to contract heartworm disease), we see a higher incidence of intestinal parasites than other parts of the country.  Please remember to have your pet’s stool checked at least every 6 months, more often if there are any episodes of diarrhea or worm-shedding.  Some households especially those with young children or immunocompromised adults, elect to keep their pets on heartworm prevention in order to reduce the risk of contact with intestinal parasites as they can have an effect on humans, too.



Even if your pet doesn’t have direct contact with a flea-infested rodent, their frequenting any space that is visited by one puts them at risk for contracting fleas.  Adult fleas live and feed on animals but their eggs, after being laid onto the hair coat, fall to the environment.  The egg hatches and a larva emerges and develops, feeding on adult flea feces, which is also shed from the flea carrier’s hair coat.  Larvae spin cocoons and become pupae.  After developing from pupae (which can lay dormant for several months), new fleas soon find an animal on which to start feeding.  It’s easy to see why fleas can be a year-round problem in the Seattle area, whether rodents enter your home or not.




Though smaller animals usually don’t survive the interaction with a larger attacking, rabid animal, all mammals including rodents are at risk of contracting and spreading rabies, usually through bites.  Please be sure to keep your pets up-to-date on their rabies vaccine.




Leptospira is a bacterium shed in the urine of many wild animals, including rats.  Our pets usually come into contact with the organism in standing puddles of water and/or moist soil but, they could also be exposed if an infected rodent urinated in your home.  Exposure to this organism can result in injury to the liver and/or the kidneys and the organism can be transmitted to people.  Most dogs in our area should be vaccinated against this organism.  Cats seem to be less susceptible to this bacterium and clinical infection in our kitties is rare.


Rodenticides / rat bait


Putting out or even having rat poison in your home can pose a serious, even fatal risk for your pet.  A pet eating a rat / rats that recently ate rat poison can also be dangerous for small and medium-sized pets.  Consider hiring a professional that specializes in households with pets to help you get a rodent infestation under control safely.

I would be remiss if I failed to mention that households that include young cats are often free from problems with wildlife in their homes.  …Just saying!


Joyeeta De, DVM

Green Lake Animal Hospital