[Passive immunization in heterakidosis].

The sera of Heterakis-infected birds influence the course of the infection caused by the parasite, lowering its survival rate and delaying the shed of its eggs. Sera containing higher amounts of gamma-globulins from five-month-old birds confer higher resistance even when applied on the 12th day of Heterakis infection to intact birds as compared to sera containing lower amounts of gamma-globulins from one-month-old birds when applied on the 30th day of infection. The drop of the survival rate of the Heterakis parasite in injecting the birds with sera from Heterakis-infected birds is due to the activation of the caecum response.