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Intestinal worms in dogs & cats: how they affect you and your pets

Published on 30 Aug 2021

Australian Shepherd Puppy sick, tired and not feeling good.

Regular de-worming for pets is an important part of their care. Worm infection in severe cases can cause illness and death to pets especially puppies and kittens, as well as being a zoonotic risk – meaning that they can infect humans as well! Which worms can our pets catch and how do they affect them?

What are intestinal worms?

Intestinal worms are parasites that usually live within the intestines of pets living off the pet's blood or the nutrients inside the intestines. They can cause different signs depending on the location of their attachment as well as the age and health status of the pet. 

The most common worms affecting dogs and cats are:

  • Hookworm
  • Whipworm (dogs only)
  • Roundworm 
  • Tapeworms, including the flea tapeworm and the hydatid tapeworm 

Pets can catch intestinal worms in different ways, including via fleas (in the case of the flea tapeworm); via faeces of other pets and animals including sheep or kangaroos; from their mother’s milk or through the placenta in utero; or from the soil and surrounding environment. 

Intestinal worms have potential to be transmitted to humans, with children being at higher risk of catching worms from pets than adults. People can catch hookworm through accidentally ingesting the larvae or from contaminated ground. They may become infected with tapeworm by accidentally ingesting tapeworm eggs. The hydatid tapeworm (Echinococcus granulosus) can cause severe illness in humans. 

Who is affected?

Any dog or cat can be infected with intestinal worms. But puppies and kittens are most at risk of becoming sick due to these internal parasites. 

According to PetSure data, pets are most likely to present to the vet with worms under 2 years of age.  

Signs of intestinal worms

The signs of intestinal worms can vary depending on the type of worm and the age and immune status of the pet. Sometimes, you may even see worm segments wiggling around on your pet’s stools! If a pet is unwell for another reason, they may be more likely to be seriously affected by intestinal worms than a very healthy pet. 

Therefore, these signs are more commonly seen in puppies and kittens and are less commonly seen in healthy adult pets. 

Worm TypeSymptoms
HookwormDiarrhoea with blood, lethargy, “potbellied” appearance, anaemia. Can cause death.
WhipwormDogs only. Diarrhoea with blood and mucous, straining to defecate. 
RoundwormVomiting, lethargy, diarrhoea, “potbellied” appearance, failure to thrive in puppies and kittens. Can cause death.  
Tapeworm“Scooting” (itchy bottom), weight loss, diarrhoea, vomiting, worm segments on stool or around pets’ bottom. 

Because healthy adult pets can have worms and not show signs, it is very important to maintain a regular schedule of worm treatment so that your pet does not become overrun by them, and so that your family and other pets don’t catch them. 

If you suspect your pet may have worms or is suffering from the above signs, don’t hesitate to get in touch with your vet for advice.

Management of intestinal worms  

Preventing worms in pets is the best option to ensure that you and your family are protected against them. 

This means regular worming with a reputable brand of intestinal worming product to the schedule that your vet recommends. For adult pets, this generally means administering quarterly worming prevention. Not all products treat tapeworm, so check the product label carefully as you may need a separate product for tapeworms. If in doubt, speak to your vet who will be able to recommend an appropriate worming product for your pet. 

In cases where a pet is sick due to intestinal worms, management relies on administering an appropriate anthelmintic (antiparasitic medications), as well as supportive care to manage the symptoms.

In very serious cases, pets may be anaemic and blood transfusions or other emergency treatments may be recommended.

Related articles:

How often should I worm my cat? 

How often should I worm my dog? 

How much does it cost to treat?

According to PetSure claims data in 2020 (calendar year), the average, single treatment cost relating to intestinal worms was $265, with the highest, single treatment cost being $2974.


  1. Virbac Australia, Intestinal worms in dogs and cats, Accessed on 27 November 2020
  2. Advantage Petcare, Intestinal worms in dogs: Get the facts, Accessed on 27 November 2020

Disclaimer: Reimbursement for these claims would be subject to limits, such as annual benefit limits or sub-limits, benefit percentage, applicable waiting periods and any applicable excess. Cover is subject to the policy terms and conditions. You should consider the relevant Product Disclosure Statement or policy wording available from the relevant provider.

Terms, conditions, waiting periods, limits and exclusions apply. is issued by The Hollard Insurance Company Pty Ltd ABN 78 090 584 473, AFSL 241436, is arranged and administered by PetSure (Australia) Pty Ltd ABN 95 075 949 923, AFSL 420183 (PetSure) and is promoted and distributed by PetSure’s Authorised Representatives (AR) Pet Insurance Pty Ltd ABN 38 607 160 930, AR 1234944 and Pet Culture Pty Ltd ABN 69 644 613 098, AR 001284860. Any advice provided is general only and does not take into account your individual objectives, financial situation or needs. Please consider the Product Disclosure Statement (PDS) to ensure this product meets your needs before purchasing. PDS and Target Market Determination available at .

Kylie Mitchell

Kylie Mitchell


Kylie Mitchell is a veterinarian with over 17 years experience in animal health and welfare, including in the veterinary and pet insurance industries

She has three rescue cats (Noah, Bei Bei and Meeka), four very old cockatiels and a pond-full of fish.

Kylie Mitchell's Pets

  • MeekaMeeka
  • Bei BeiBei Bei
  • NoahNoah