Roundworms, also known as ascarids, have round bodies and are 7-12 cm long. They live in  dogs’ intestines on partially digested food.

Pups infested with roundworms lose weight and look pot-bellied. They lose their appetites and may vomit or develop diarrhoea. Serious roundworm infestations obstruct or twist the bowel.

Most puppies acquire roundworm infection from their mothers before birth and then through the milk afterward.

Both puppies and adult dogs are also infected by swallowing roundworm eggs from bowls, hair or dirt contaminated with faeces. They can also be infected by roundworm larvae encysted in the organs of prey like mice, cockroaches, earthworms and chickens.

Ingested larvae and eggs are activated in the dog’s stomach and small intestine and migrate through the muscle, liver, and lungs. After several weeks, the larvae make their way back to the intestine to mature. When these worms begin to reproduce, new eggs will pass in the dog’s faeces, and the life cycle of the parasite is completed.

Roundworm eggs in the faeces confirm roundworm infestation. Because roundworm don’t produce many eggs we sometimes have to examine several fecal samples before we find eggs. Occasionally, we see mature worms in the dog’s vomit or faeces.

Treatment with broad-spectrum wormers like Milbemax or Drontal eliminates adult roundworm. No treatment reliably kills the migrating larvae so we give two or three treatments 2 weeks apart catch them as they mature into adult worms.

The eggs are resistant to most disinfectants and survive in quite harsh environmental conditions. They remain infective to dogs and humans for years.

Regular removal of dog faeces and deworming as detailed below prevent reinfection.

Roundworms are a risk to human health.  Children and people who are immunosuppressed or on immunosuppressive drugs are particularly vulnerable. The roundworm eggs only develop as far as larvae in people. As the larvae migrate through the body they can cause damage, particularly to the eye. Worming people does not kill the larvae as only adult worms are susceptible to wormers. To prevention human infestation

• Deworm pups fortnightly until 12 weeks of age, then monthly until 6 months of age. Adult dogs must be dewormed every 3 months
• Remove and dispose of dog faeces promptly
• Teach children to wash their hands thoroughly after playing with dogs
• Deworm pregnant bitches in late pregnancy and then every time her pups are dewormed, as above
• Discourage dogs from defecating in children’s play areas