Preventing E. Coli Infections in Dogs

E. coli infections can cause serious illness in both humans and dogs. Here's what you need to know.

By: tys720
E. coli is already in the gut. By: tys720

With E. coli’s reputation for causing serious illness, you may be surprised to learn that you are already intimately acquainted with this bacterium.

This is because E. coli (Escherichia coli) is a normal inhabitant of the lower bowel in many mammals — including humans.

Why it makes some animals ill, but not others, is poorly understood. The most likely explanation is the strength of the host’s immune system in fighting off infection. This would also explain why very young, very old or already-sick animals are most likely to become seriously ill from colibacillosis (infection from E. coli).


Newborn puppies and kittens are especially vulnerable to E. coli, which can cause blood poisoning that can in turn lead to organ failure. These very young animals are cold, weak and frequently have diarrhea.

If a puppy or kitten is a little older, then sickness and diarrhea are the most likely signs — but be aware, these can also be symptoms of many other conditions. Having diarrhea is not a diagnosis in itself.

Elderly animals will show different signs depending on what bodily organ is infected. Diarrhea is a common sign, but animals can potentially have cystitis, mastitis, endometritis or pyelonephritis (respectively, infection of the bladder, mammary gland, womb or kidney).


This bacterium normally lives in the gut where it doesn’t cause problems because the host’s immune system keeps it in check. But if the animal eats contaminated meat or drinks from a puddle containing E. coli, this massive extra dose can overwhelm the immune system and make the pet ill.

If a nursing female dog has E. coli in her bloodstream, the bacteria could circulate and settle in her mammary glands, causing mastitis. The milk can then infect the puppies with E. coli when they suckle.

Because puppies’ immune systems are not yet fully formed, E. coli makes them vulnerable to serious, sudden onset illness and death from colibacillosis.


Making a definitive diagnosis can be tricky. There is little point in screening feces for E. coli because it is a normal gut inhabitant. And routine blood tests give a general picture of dehydration rather than a specific diagnosis.

The most conclusive test is to culture E. coli from blood or tissue — this can be difficult in very small puppies and kittens, and it may mean taking tissue samples at post-mortem to give an answer posthumously.


Key to successful treatment is replacing fluids lost through diarrhea, giving antibiotics to kill the E. coli and first-class nursing care.

Young animals in particular are prone to low blood sugar levels and losing heat; thus, giving regular oral glucose supplements and keeping youngsters warm can make the difference between a successful outcome or not.


There are a number of things that help decrease the chances of young puppies and kittens acquiring a serious E. coli infection.

It is vital that they suckle colostrum within a few hours of birth. This highly nutritious milk is antibody-rich and primes their immature immune systems. Likewise, it helps if the dam is in good health and is not harboring a low-grade infection before she whelps which she could then pass onto her pups.

Factors such as a dirty environment or overcrowded kennels add to the background level of contamination and should be avoided.

Regular disinfection of whelping facilities and keeping the number of animals down in any particular kennel is a basic requirement. And don’t forget, humans can become infected, so regularly washing our hands after any contact with animals, especially before eating, is key.


  • Small Animal Internal Medicine. Nelson & Couto. Publisher: Mosby. 3rd edition.


This pet health content was written by a veterinarian.

* * *

Get Free Recall Alerts! Sign up now to Petful’s twice-monthly email newsletter, and you’ll also get our FREE pet food recall alerts. You’ll be among the very first to know about recalls. Click here to sign up now (it’s free).

Popular From Petful

Join the Conversation

Join the Conversation


  1. aamy Reply

    I cant possibly be the only pet owner in Streator IL who had 4 sick dogs because of e-coli in the water… The first dog that was sick was the 6lb Pomeranian… she got so dehydrated from vomiting and diareha that she spent 3 days on IV fluids and antibiotics at the vet…. cost over $300. The second who got sick was the Westie… whos bigger and didn’t dehydrate as fast… but was sick for 4 days and i treated her with prescription food n antibiotics left from the pom… my 150lb lab didnt eat for 4 days and i thought i would have to take him too…. i bought soft food and other treats and finally he started feeling better and eating…. all that was left was my 4 lb chiuauha… as soon as she vomited the first time i panicked… shes not big enough to be as sick as the others… i took 24/7 care of her for 4 days… not even sleeping… she drank an entire bottle of pedialite(the childrens medicine)… every 15 minutes i gave her a swallow for days…. just to make sure she wouldnt dehydrate…. i almost lost two of my 4 babies… then i found out there was a boil order for ecoli in the water…. 8( i had been dealing with this for a week and a half already… how did they now know? and has anyone lost a pet? i would have been devastated… i was anyway… guess im just venting… but i so went thru a very scary situation that could have been prevented??? Im just blown away…..

    1. David Deleon Baker Reply

      Ugh, that’s awful. Haven’t heard about any outbreak like this.

  2. ayla Reply

    I have a 9 week old pitbull puppy. The litter i got her from all but 1 have died from the same symptoms, including mom. The owner thought mom had been poisoned. All of the other pups have died within 2 weeks of each other. My little one is going through it now. I have went through every possibly cause&this seems the best fit. Its classic parvo symptoms but 5 different pups in 5 different locations couldnt possibly have gotten parvo when they have all had their shots, could they? Im racking my brain trying to figure this out. I have been giving her pedialyte every 15 mins trying to keep her hydrated&praying that it works. I would love to hear other suggestions&opinions

    1. Pets Adviser Reply

      Hi Ayla,

      Sorry to hear your puppy is sick. It’s important that you take her to a veterinarian/clinic right away to diagnose the problem and get the right treatment for it. Best of luck. As you say, other puppies have already died, so time is of the essence to seek treatment now.

  3. Aj Reply

    Hello my nana has e-coli and my eight year old dog was just licking food from her plate..I dont think he got much because I stopped him as soon as I saw him..but should I be worried? Is there anything I can do to flush it case he did get something?
    Thanks Aj

    1. Pippa Elliott Reply

      Hi AJ,
      I’m sorry to here your Nana had a encounter with E.coli, I hope she is on the mend and feeling much better..
      I would suspect there would be very little contamination on the plate, especially if your Nana was eating with a knife and fork. Most healthy dogs have strong enough immune systems to see of a small challenge from E.coli, but if you are worried, have a word with your local veterinary clinic and see if you can collect some doggy probiotics. These will improve the gut’s immunity and the probiotic bacteria will hopefully outnumber the E.coli. Of course, if your dog develops an upset tummy, please take him to see your vet asap.
      Best wishes to your, your dog, and of course…Nana.
      Dr. Pippa