Worm infestations are common in dogs and cats, and knowing how to spot the signs early can ensure your pet stays healthy and happy. Worms can cause several health problems, ranging from mild discomfort to serious illness. Here’s how to determine if your pet has worms and what to do about it.

What are intestinal worms?

Intestinal worms are parasites that live in your pet’s intestines, feeding on blood or other nutrients. There are four main types of intestinal worms in pets to be aware of:


Roundworms are one the most common types of intestinal worms in pets. The adult worms, resembling long strands of spaghetti, live in the small intestine. Infestations are particularly common in kittens and puppies, who can get roundworms from their environment, from their mother in the womb, or through her milk while nursing.

Symptoms of roundworm infestation in puppies and kitten can include a pot-bellied appearance, stunted growth, vomiting and diarrhoea.


Hookworms are smaller than roundworms but can still cause severe disease, particularly in young pets. These adult worms attach to the intestinal wall and feed on blood with their sharp, biting mouthparts, which can cause bloody diarrhoea, weight loss and anaemia. In severe infestations, the level of blood loss can be fatal. Pets with hookworm infestations will pass eggs in their faeces, which hatch into larvae.


Tapeworms are long, flat, segmented worms. The flea tapeworm is the most common tapeworm affecting cats and dogs in Australia. Infestations occur when pets ingest fleas containing flea tapeworm larvae during grooming. Signs of infestation include scratching or licking their bottom and visible tapeworm segments in their faeces or around the anus, which resemble small white grains of rice.

Another important tapeworm for dogs is the hydatid tapeworm, which can affect dogs in rural areas if they eat raw offal or scavenge on farm animals and wildlife carcasses.

Hydatid tapeworm can cause significant illness in humans, so speak with your vet to find out if your dog may be at risk.


Whipworms are parasites of the large intestine that affect dogs but not cats. The symptoms of whipworms can include watery or bloody diarrhoea, weight loss and lethargy. Whipworm infestations can be fatal in severe cases with high numbers of worms. Dogs become infested with whipworms by ingesting whipworm eggs from a contaminated environment. Whipworm eggs are very resilient in the environment, remaining viable for years even under extreme environmental conditions.

Signs your pet may have worms

Watch out for the following signs of intestinal worms:

  • Diarrhoea
  • Vomiting
  • Bloated stomach (pot belly)
  • Changes in appetite
  • Weight loss
  • Pale gums
  • Itchy bottom

Sometimes, worms or worm segments might be visible in your pet’s faeces. However, not all worms are visible to the naked eye, so if you don’t see them, it doesn’t rule out an infestation.

If you notice any of these signs, book an appointment to see your vet so they can assess your pet, carry out necessary diagnostic tests and make a diagnosis.

Other worms to be aware of

Feline lungworm

As the name suggests, lungworms reside in a cat’s lungs. In Australia, two lungworm species infect cats, the most common and harmful one being the cat lungworm (Aelurostrongylus abstrusus). Cats can get lungworms by ingesting an infected snail or slug or eating a rodent, lizard, or bird that has consumed an infected snail or slug. Adult worms live in cats’ lungs and cause significant respiratory diseases.

Signs of infection can range from mild or even no symptoms to severe respiratory issues, with kittens being at higher risk. Affected cats may show coughing, wheezing, and breathing difficulties. Lungworm infections can be mistaken for feline asthma or chronic bronchitis and, if left untreated, can cause severe and irreversible lung damage.


Mosquitoes transmit heartworms, which can cause significant damage as they migrate through your pet’s body, and heartworm disease can be fatal. This disease is seen throughout mainland Australia and affects both dogs and cats. However, dogs are more commonly affected.

Although heartworm infestations are most common in regions with high mosquito populations, cases have been diagnosed in nearly all parts of Australia. Heartworms live in the heart and blood vessels of the lungs, disrupting circulation and damaging tissues, which can eventually lead to heart failure. If left untreated, heartworm disease can be fatal.

Infested pets will typically show no signs of illness initially; however, as time goes on, signs may develop, including coughing, lack of energy, reluctance to exercise and weight loss.

How do pets get worms?

Pets can get worms in many different ways, such as by ingesting roundworm eggs while sniffing around at the dog park, swallowing a flea that contains flea tapeworm, being bitten by a heartworm-infected mosquito, or hunting or scavenging.

Puppies and kittens can even get worms from their mum in the womb or through her milk.

Can worms be transmitted from pets to humans?

The short answer is yes; many worms that infest dogs and cats are zoonotic, meaning they can be transmitted to humans. Different worms cause different diseases, with various symptoms, potentially affecting the eyes, skin or internal organs. Children, the elderly, and people who are immunocompromised are at a higher risk. Always consult your doctor if you have any concerns about symptoms.

How can I prevent my pet from getting worms?

Preventing worms is easier than treating an infestation. NexGard SPECTRA for Dogs provides the most complete protection against fleas, ticks, mites, heartworm and intestinal worms, all in one tasty, monthly chew. It can be used from 8 weeks of age and 1.35 kg bodyweight.

NexGard SPECTRA Spot-On for Cats provides the most complete protection against fleas, ticks, mites, heartworm, lungworm and intestinal worms (including tapeworm), all in one easy, topical treatment. It can be used from 8 weeks of age and 0.8 kg bodyweight.

Talk to your vet to help you choose the right product for your pet.