Roundworms are a common intestinal parasite of dogs and cats. Eggs are shed in feces, become infective in the environment over several weeks and then can infect people that ingest these eggs. Once inside the human body, the eggs develop into larvae (immature worm-like stage) which then migrate into the eyes or internal organs (eg: liver and kidneys). The ocular form is known as Ocular Larva Migrans (OLM) and can lead to blindness, while the internal organ form, called Visceral Larva Migrans (VLM), causes a variety of diseases depending on which organs are affected.
Infection can occur in both adults and children. The infection most commonly occurs by ingestion of infective eggs from contaminated soil and sand found in gardens, playgrounds, sandboxes, parks and beaches and by eating unwashed/contaminated raw vegetables. Children under the age of 5 years have an increased risk of infection since they often play in potentially contaminated backyards and playgrounds and sometimes eat dirt or put their unwashed fingers in their mouths.
Eggs can remain viable in the soil for years depending on the environmental parameters (temperature, humidity) and can only be killed by extreme heat (steam/fire) or from prolonged exposure to UV radiation (sunlight). Snow can often insulate the eggs and allow them to survive the cold winter weather.
Because of these potentially serious health risks, the Companion Animal Parasite Council (CAPC) recommends that puppies and kittens be dewormed every 2 weeks until 12 weeks of age and then once per month until they are 6 months old. Deworming can be started as early as 2 or 3 weeks of age. Adult dogs and cats should be dewormed a minimum of 4 times per year.
In addition to regularly deworming all pets and picking up their feces, adults and children should adhere to good hygienic practices… keep fingers out of mouths, wash hands thoroughly and regularly, wear gloves while gardening and don’t eat unwashed vegetables.