4 Common Infections That Cause Diarrhea in Puppies

From worms to parvovirus, puppy diarrhea can be caused by several different ailments.

My girl had not 1 but 4 types of infections that gave her diarrhea. Photos by: Pippa Elliott
My girl had not 1 but 4 major problems that gave her diarrhea. Photos by: Pippa Elliott

As someone with a puggle puppy, I’m all too familiar with poop.

My new fur-family addition came with several unwanted extras in the tummy department in the form of campylobacter, roundworms, tapeworms and giardia.

Well, 2 fecal analyses and 3 courses of treatment later, I’m relieved to say she now passes PFPs (perfectly formed poops).

A History of Infections

My puppy didn’t have the best start in life and picked up her infections by contact with feces in the unhygienic conditions she lived in. When dogs come into contact with poop, they can catch all sorts of diseases, especially the very young whose immune system isn’t strong enough to protect them.

My recent experience of anxiously awaiting the next bowel movement to see if there was any improvement helped me view puppy tummy upsets from the other side of the consulting room table.

It has taken nearly 4 weeks to go from bloodstained, mucoid diarrhea to PFPs, so have a little patience if your puppy’s poops aren’t perfect yet despite a course of treatment. It can take a while to get to the bottom of things because your pup might have more than 1 infection (or 4, in my pup’s case).

1. Worm Infections

Worms are top of the charts when it comes to puppy poop infections.

  • The granddaddy is roundworms (Toxocara), with the mother passing larvae onto her pups in the womb and via her milk. It’s safe to assume your pup has Toxocara and to worm repeatedly — those larvae hatch out regularly, especially during the first 6 months of life.
  • Tapeworms (Dipylidium) go hand in hand with fleas, so the pup with passengers of the jumping sort is almost guaranteed to have tapeworms. The worms in the gut produce egg packets that migrate out of the pup’s anus and causes extreme itchiness, so be vigilant to the bottom-obsessed youngster constantly scooting or trying to chew under the tail.
  • Whipworms (Trichuris) and hookworms (Ancylostoma and Uncinaria) are also common and easy to catch. The eggs are extremely hardy and can survive for years in the environment, so it’s easy for a puppy to accidentally pick up infection. The signs include watery, bloody diarrhea, with the diagnostic challenge being fecal analysis that often gives false negatives due to lack of egg shedding at the time of sampling.
That belly! She's doing better know after treatment.
That belly! My puppy is feeling much better now after treatment.

2. Protozoal Infections

Other common gifts passed from mother to pups (usually those kept in unhygienic conditions) are giardia and coccidian infections.

Giardia is a single-celled organism from the family of organisms that causes amebic dysentery in people. Again, the cysts can persist in a moist environment for many months, making infection common. There are at least 6 species of coccidian that affect dogs, of which Cryptosporidium is the biggest problem in puppies.

One problem with protozoal infections is the risk of reinfection in the same pet — the cysts can cling to fur, ready to be ingested when the pup washes himself.

3. Bacterial Infections

Did you know that, on average, 1 gram of dog feces contain 23 million fecal coliform bacteria? That’s a lot of bugs, all with the potential to cause stomach cramps, diarrhea and kidney disease.

From salmonella to campylobacter, several bugs can affect puppies. These can cause debilitating diarrhea with the added risk that they can be passed onto people. Diagnosis of the individual bug and targeted treatment depends on fecal analysis.

Here’s Dr. Karen Becker, DVM, with more about diarrhea in pets:

4. Viral Infections

The deadliest virus on our list is parvovirus, with signs occurring 2–5 days after infection, including life-threatening bloody diarrhea and vomiting. Parvovirus is the Schwarzenegger of the virus world and can survive against all the odds in the environment, with vaccination being essential to maintaining good health.

Distemper can also cause diarrhea amid a host of other symptoms such as coughing, sticky eyes, fever and vomiting.

Less dramatic is coronavirus, which causes diarrhea in pups because of their weak immune systems. But — provided they don’t become dehydrated — it in itself isn’t deadly.

Treatment of Puppy Diarrhea

If you see blood in the stool or your puppy is vomiting, contact your vet immediately.

Diarrhea can be deadly if your pet becomes dehydrated, so it’s important to keep his fluid intake up. Check the gums to make sure they feel moist — dry-feeling oral membranes are an early sign of dehydration. Syringe in electrolyte solutions to keep hydration steady.

If the puppy is bright in himself, offer a bland diet of white meat with boiled rice or pasta, or a prescription diet designed for upset stomachs. Straightforward diarrhea should settle within 48 hours, so if the problem persists, seek veterinary advice.


This pet health content was written by a veterinarian, Dr. Pippa Elliott, BVMS, MRCVS. It was last reviewed Oct. 13, 2018.

Dr. Pippa Elliott, BVMS, MRCVS

View posts by Dr. Pippa Elliott, BVMS, MRCVS
Dr. Pippa Elliott, BVMS, MRCVS, is a veterinarian with nearly 30 years of experience in companion animal practice. Dr. Elliott earned her Bachelor of Veterinary Medicine and Surgery from the University of Glasgow. She was also designated a Member of the Royal College of Veterinary Surgeons. Married with 2 grown-up kids, Dr. Elliott has a naughty puggle called Poggle, 3 cats and a bearded dragon.

Please share this with your friends below:

Also Popular

Do NOT follow this link or you will be banned from the site!