Safety features of the MLV PRRSV vaccine strain (VP-046 BIS) when administered to 3 weeks old piglets in an endemically infected farm.

摘要

Safety features of MLV PRRS vaccines are a major concern for pig producers worldwide. The capability of US MLV PRRSV vaccine strains to be shed from vaccinated to non-vaccinated pigs has been widely studied in both experimental and field conditions. On the other hand, previous studies showed that EU MLV PRRSV strains can reach the foetuses without any apparent clinical effect when injected to naive pregnant sows 2. In endemically infected herds, sows and piglets may develop a humoral response againstPRRSV. This would suggest that the vaccine virus shedding would be lower, when vaccinating these animals than in naive pigs. The aim of this study was to monitor the eventual transmission of a live EU MLV PRRSV vaccine strain (VP-046 in AMERVAC PRRS~R)from 3-week-old vaccinated piglets to their litter piglet mates in a PRRSV-endemically infected farm.