Zoonoses written by Dr. Dave Kerr

I have my dog and cat on parasite protection during the summer. Are there any parasites they carry that can be passed to me or my family?

Safe Dad


Dear SD,

When diseases can be passed from one species to another they are called Zoonotic diseases. The rabies virus is the most dangerous  Zoonotic disease of pets because it is invariably fatal. There are certain parasites of dogs and cats that are zoonotic and can cause serious life altering disease when passed to humans.

The most important parasites are the common Roundworm and  Hookworm of dogs and cats. Both worms enter by eating infected food and the Hookworm can also enter the human body by penetrating the skin. When either worm enters a human they get “lost” looking for a dog or cat. When lost they find new homes in odd places like the eye, the brain and muscle any of which can lead to debilitating consequences.

Tapeworms are passed in the stool of dogs and cats in small ‘egg packets’ which look like grains of rice. Zoonotic infection happens when these are swallowed. This sounds very yucchy and no one would ever do this unless a pet sleeps with you and you accidentally swallow one while sleeping.

Toxoplasma is a parasite of kittens and cats. Pregnant ladies and immunocompromised individuals are at most risk of this zoonosis. Precautions need to be taken when cleaning the litter box and those people at risk should avoid cleaning the litter box if possible.

Fleas, mange mites and ticks are external parasites that can be passed from pets to people. These are more annoying than harmful unless the ticks carry Lyme disease. In the 17th century it was the fleas of rats that spread the bubonic plague through Europe.

There are a number of parasites we can be afflicted with that our pets get unfairly blamed as the source of infestation. Lice and pinworms are the most common. Dogs and cats can be infested with lice but these parasites are host specific meaning they will not transfer from pets to people. Neither dogs nor cats suffer from pinworms which can infect young children. The culprit in these infections is usually another young child.

Having pets in the family enriches and completes the family. Pets’ health must be maintained for their safety and the safety of the family. Regular examinations by your veterinarian and a regular deworming schedule like your pets are on, will help keep all family members free of dangerous parasites.

Let our North Hill veterinary team in Bolton know should you have any more questions,

Dr. Kerr