[Negligible risk of visceral or ocular larva migrans from petting a dog]

In a recent publication it was suggested that human toxocarosis, including ocular larva migrans, may result from petting dogs infected with Toxocara canis, the dog roundworm. Recalculating the eggs per gram in the dog's coat revealed that in 7 of the 15 positive dogs only one Toxocara egg per dog was found. Only 4% of all eggs were embryonated and hence infectious. It is, however, very plausible that this is contamination originating from the environment. The authors found also many other parasite eggs and free-living larvae in their samples, which points to the dog being merely a passive transport host. The risk to man of acquiring the infection by stroking a dog is therefore considered to be extremely limited.