Worms and your family


Dogs and cats with hookworm infection may be not show any symptoms or develop diarrhoea, weight loss, anaemia and lack of appetite. The source of infection is soil contaminated with infected faeces (poo) of dogs or cats. Eggs are shed in faeces and develop into infective larvae in the soil. People are infected when gardening without gloves or when children play in sandpits or on the grass. In people, hookworm larvae penetrate exposed skin and lesions appear as tracks under the skin (referred to as cutaneous larval migrans). Common after rain or in moist areas.


worms and your dog
Larva found in a human’s eye. This can cause blindness.

Each species of roundworm is adapted to survive within a specific species of animal. Certain Toxocara and Toxascaris species of roundworms are specifically adapted to survive within the bodies of dogs and cats. If a human accidentally ingests a roundworm egg from a dog or cat, the developing larva will become confused in the strange environment and will migrate from the foreign digestive tract to various organs throughout the body, potentially causing serious health problems. This process is known as visceral larva migrans. An immature larva that migrates to the eye can lead to blindness in a specific process known as ocular larva migrans. If a human picks up the microscopic eggs on their hands, through contact with an infected animal or contaminated soil, then accidental ingestion may occur unless thorough hand-washing techniques are followed regularly. Young children or adults with weakened immune systems are particularly prone.


  • Maintain good hygiene at all times. This means washing hands thoroughly after petting or playing with your pets (especially puppies and kittens,) This is especially important to stress to children.
  • Cleaning up after your pets in a timely manner. (Frequent poo pickups!) If not removed from the environment, roundworm eggs can survive for months to years and may reinfect your pets at any time. And they are destroyed only by heat that is 60-70 degrees (similar to a flame thrower, which is not our recommended method of worm control). Covering sandpits and good litter tray hygiene is a good idea.
  • Have your pets screened or treated for internal parasites regularly by your veterinarian.

This means diligently testing/treating puppies and kittens multiple times during the first several weeks of life (usually as part of the new puppy or kitten exam and appointments for vaccine boosters,) as well as each year during your pet’s annual wellness exam. Many products are now available to prevent internal parasites on a monthly basis in dogs and cats. It is not always possible to diagnose intestinal parasites from a single slide, as it depends on the number of eggs that are shed.

Why do you treat multiple times?

The worms goes through several stages during their life cycle, from egg to immature larva to mature worm over a period of between 5 and 10 ½ weeks, depending on the species. For example, the canine (dog) roundworm takes 6 weeks to fully develop. Common treatments may not work at all stages of the parasite’s life cycle, so animals are usually medicated multiple times to clear the infection.

Heartworm disease (dirofilariasis)

Dirofilariasis is transmitted to dogs, cats and people through bites from infected mosquitoes. Microfilaria (heartworm larvae) migrate through tissues until reaching the heart. In dogs and cats microfilaria develop into adult heartworm and cause heart and respiratory disease. In people microfilaria do no survive but lung emboli can develop and cause respiratory infections. These can mimic the signs of lung cancer on X-ray.

Prevention of infection
  • Reduce the risk of being bitten by a mosquito using repellents and fly screens.
  • Ensure your cat or dog is up to date with heartworm prevention.