All dogs have an infection with roundworms called Toxocara Canis at some time during their lives, and puppies are almost always worst affected. The disease is called Toxocariasis. This is one of the potential diseases that can also affect humans but there has been considerable scaremongering.
As the eggs of the Toxocara worm take over two weeks to hatch and become active, there are no health risks to you from immediately clearing up after your dog providing you use sensible hygiene precautions.
In tests, only five per cent of pet dogs were found to expel Toxocara worm eggs. This is probably because many dogs are regularly wormed.
Of this five per cent, the majority were pups between two weeks and six months of age or pregnant bitches.
Foxes and cats also act as hosts to the Toxocara worm although the cat worm is slightly different.
The incidence of all Toxocara-induced diseases in the UK is less than two cases per million of the population. However, this still means that up to 40 people are needlessly ill each year.
The eggs of the Toxocara worm, if deposited in soil, can lie dormant for many years, if the conditions are right. They are highly resilient to temperature changes and chemical disinfectants have little effect on them.