Serological response of ascarid-free dogs to Toxocara canis infection.

Antibodies to Toxocara were measured by enzyme-linked immunosorbent assay (ELISA) in sera of ascarid-free dogs which had been fed 0, 100 or 10 000 embryonated T. canis eggs. Dogs fed 10 000 eggs developed higher titres than those given 100 eggs and larvae failed to complete their migration to the gut. In addition, in dogs given 100 eggs, there was a significant negative correlation between the number of worms in the gut and granulomatous foci in the lung. The data suggest that the ELISA is sensitive and specific for Toxocara infection in dogs.