How Rats Can Harm Cats & Dogs

How Rats Can Harm Cats & Dogs

dog and cat

Most people are surprised to learn that while dogs and cats are usually seen as a natural enemy of rodents, rats can present a number of health problems and dangers to these common pets. Many farmers have traditionally kept cats and a dog or two to help ward off and reduce rodent populations.

Rodents can destroy crops, eat grain, nest in the hay, and cause a threat to pets and livestock. In order to understand how serious the rodent threat to dogs and cats is, you need to know something about rats in particular. 

Rats Will Run, but They Really Aren't Afraid 

Rats are rodents and it is their nature to run when they see larger animals heading in their direction. However, rats are not nearly as timid and afraid of bigger animals as their mice cousins. In fact, if you corner a rat, it may just attempt to defend itself by leaping at and biting you. This is often what happens when a dog or cat corners a rat and a rat's bite is a carrier of many major diseases. 

When a rat bites your dog or cat, it can transmit a number of diseases through the rat saliva into the wound of the bite. If your dog or cat is not up to date with all of its current shots, it may fall ill, infect others, or worse.

lab tests

Leptospirosis in Cats and Leptospirosis in Dogs 

Simply known as "lepto" in the veterinary medicine world, it generally doesn't do a lot of harm to cattle and rats. It does affect their kidneys such that they urinate quite a bit and it can lead to dehydration, kidney disease or death if left untreated. While you may treat cows and cattle for lepto, you aren't going to treat any rats in your barn or stable. 

Leptospirosis in cats and leptospirosis in dogs, however, is another story. It is not only damaging to their urinary systems, but they can also transmit it to humans and other pets in the household. The internal damage it causes is severe enough in some cases to cripple the affected animals or humans and leads to death. Preventing lepto is your best bet, as treating it is difficult and costly. The best prevention of course is catching and dispatching as many rats and mice on your property as you can. 

cat with rat


Hantavirus is a very serious disease carried in infected rats and rat droppings. Oddly enough, dogs can develop antibodies to the virus, and cats do not seem particularly affected either. The problem comes when these animals kill infected rats or bring their kills to your doorstep as "presents" and introduce the virus to you. 

Hantavirus weakens blood cells and causes major pulmonary damage in humans, if you survive it. Putting a different option in place to catch and kill rats removes the possibility that your pets will wander around your property killing something that is infected with hantavirus and bringing it back to you. Additionally, if they have the virus and bite you and break the skin, or they walk through infected rat droppings and then scratch you creating an open wound, you could become infected. 



If you have ever been pregnant, or you have heard pregnant women talking about how they can't change the litter in a cat box, then you know a little something about toxoplasmosis. It is a disease that starts in rodents, migrates to hunting cats, and finally ends up in humans when humans clean litter boxes of infected cats. The cat is the intermediate host for the toxoplasmosis between rats and humans and the disease can cause serious health risks to pregnant women and lethal risks to an unborn baby. 

Women who have cats at home are often tested during pregnancy to make sure that they have not contracted toxoplasmosis from their cats. Yet the best way to prevent it is to not allow cats to hunt rodents at all and kill the rodents as quickly as you can. There are some excellent and quick-kill traps available on the market for just that purpose. 

You should also know that dogs are rarely carriers of this disease, and even if they do have it, you would never know it. Given that most dog owners do not scoop dog feces with their bare hands, the risk is particularly low for dog owners contracting toxoplasmosis from their canine friends. 


Rat Bite Fever 

Even though this sounds like a made-up illness, it isn't. If you stop to think of all the vile stuff rats eat and that their mouths are essentially rotting garbage disposals, you can understand why a bite from a rat can cause quite a nasty, fever-producing infection. If you are lucky, the rat isn't hoarding nasty bacteria in its mouth that can cause rat bite fever. If your cat or dog isn't so lucky, it may require treatment to eliminate the bacteria from the bite wound(s) and the body. 



Fleas and Ticks 

Rats go everywhere. They will scurry through high grasses, up into trees and through bodies of water (including sewers!). Along the way they pick up a lot of nasty, blood-sucking parasites that will jump from a dead rat onto your live dog or cat when these parasites realize that their rodent host is now dead and not a live blood meal.

 Along with the transference of the parasites, whatever the parasites are carrying is transferred as well. That includes lyme's disease, which dogs and cats can contract, and bubonic plague (or just "plague"). These are diseases which humans can also contract from the fleas and ticks brought back into the home by the dogs or cats that killed the rats that were carrying these insect pests. Serious rat diseases and illnesses are preventable if you pre-treat your pets for fleas and ticks and keep them from chasing and killing rodents. 

dog at vet

Other rat diseases 

There are other rat diseases that are either directly or indirectly transmitted to dogs and cats and then to humans. Prevention is essential to stopping your pets from contracting these diseases and/or lifelong illnesses that can affect their quality of life. Since some of these diseases and illnesses can also be transferred to you, it is in your best interests to take all necessary measures to eliminate rodents from your property before they can harm your furry friends, your family, and you. If you want to know more about traps we offer, contact us today at

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