A UK man is on a campaign to raise awareness about Toxocara, following an infection that blinded the child of a family friend. Mike Kennedy, chairman of the Grange Residents’ Association, is  raising awareness about the importance of picking up "dog dirt" (i.e. dog stool).

Toxocara canis is an intestinal parasite that can be found in a small percentage (likely 2-14% in Ontario) of healthy dogs, and a larger percentage of puppies. Toxocara cati is the feline equivalent found in a comparable proportion of cats. If a person swallows an infective egg – an egg that was passed in an animal’s stool and allowed to sit around in the environment for a while – infection can occur. The parasite can migrate throughout the person’s body, causing various types of problems. Migration into the eye (ocular larval migrans) can cause blindness. Migration through the brain (neural larval migrans) can cause serious brain injury. These are very rare diseases, but are obviously still a concern because of they can be so severe. The risks are highest in children and people with developmental delays, since they’re more likely to swallow stool, dirt, or something else contaminated with stool.

Mr. Kennedy’s emphasis on educating animal owners to pick up after their pets is the key. We know a small percentage of dogs and cats shed Toxocara in their stool. You never know exactly who is shedding the parasite at any time, so removing the source of parasite eggs, the stool, is critical.  Deworming pets regularly is also important, but it is only one component of parasite control. The frequency and type of deworming needed for dogs and cats varies between regions and animals.  Your veterinarian can design an appropriate deworming program for your pet. Such a program requires a balance between adequate deworming to reduce the risk of parasites in pets (and the associated risk for human infection) and using dewormers prudently to reduce the risk of parasites developing resistance to these drugs.

Photo credit: Michael Lazarev (Clyde, the bulldog puppy)

  • Victoria Clare

    I am wondering about your statement that “educating animal owners to pick up after their pets is the key.”

    Surely in the UK, where this story comes from, Toxocara canis is carried by a high percentage of the native red fox population, and Toxocara cati is common in the large feral cat population?

    Picking up after pets is of course highly desirable for many reasons, but is it really going to make that much difference to toxocara infection rates specifically, given that pets are more likely to be regularly wormed than wild or feral animals, so are presumably less likely to be a source of infection?

    I live in the UK, and I’ve never lived anywhere where red foxes were not present in fairly large numbers, so I tend to assume that all soil could be infected, whether or not pets have access to it.

  • Scott Weese

    It’s a good comment and certainly wildlife can be a source of contamination in some areas. However, the degree of contact between pets and public places (esp. personal spaces such as backyard) it presumably much higher than wildlife. Also, wildlife have variable defecation patterns and some are not known for defecating in public/high transit areas. We’ll never eliminate the potential wildlife course but there’s not much that can be done about it apart from standard hygiene. Removing pet feces is a much more practical approach and while it doesn’t eliminate the risk, it should be a key preventive measure.

  • Judy

    Does deworming kill Toxocara?
    I think a large percentage of pet owners do NOT regularly deworm their adult pets, and those who do not bother to pick up their pet’s droppings in public places are probably the least likely to regularly perform deworming.