Children get toxocariasis when they are infected with the eggs of roundworms (Toxocara canis) from the faeces of dogs. The infection happens when the child gets soil or sand contaminated with faeces into its mouth. Once the eggs are inside the child’s digestive tract, they move into the bowel where they hatch into larvae.
The larvae burrow through the wall of the intestine and through the soft tissues to, most commonly, the lungs, liver, eyes, and brain, where they can cause symptoms that range from a mild fever to blindness (don’t click this link if you are squeamish).
It’s hard to tell how many of these infections cause illness, but research in the USA, at the turn of the century, found that 13.9% of children aged upwards of 6 years had Toxocara canis antibodies in their blood, which showed that they had been infected at some time in their lives. Similar research in Sri Lanka found a 50% incidence.
In the park we have a combination of children and dogs that makes it particularly important that we are vigilant. Almost every dog will get roundworms at some time in its life and, at any one time, about 20% of dogs are infected. This means that one in every five dogs that comes into the park will bring with it mature roundworms, each one of which can lay 200,000 eggs every day, for a rolling, tumbling, thumb-sucking toddler to put in his mouth.
People are very careful about picking up on the central path and we are grateful, but some are less conscientious when their dogs poop in the grass, which is, of course, where our children play. Please clean up after your dog. Toxocara eggs are not infectious for the first 10–12 days so you are in no danger as you poop-scoop, but they can live in the soil and be infectious for many, many years afterwards if you don’t scoop.
This is the first post of a spring campaign; let’s keep our park poop-free.
Pictures: Google Images