Experimental efficacy of vaccination of weaned piglets with a modified-live commercial PRRS virus vaccine against the challenge with a Spanish highly virulent PRRSV-1 strain.

Background: In 2020, a highly virulent PRRSV-1 strain emerged in Spain and rapidly spread across the country. The purpose of the present study was to test in a piglet model whether a commercial PRRSV-1 modified live vaccine was able to confer protection against strain R1, a representative of the emerging clade. For that purpose, two groups of 26 piglets were either vaccinated intradermally or kept as controls; 42 days later, half of the animals in each group were intranasally challenged with the R1 strain.

The introduction of a highly virulent PRRSV strain in pig farms is associated with a change in the pattern of influenza A virus infection in nurseries.

The present study aimed to determine the dynamics of influenza A virus (IAV) infection in two endemically infected farms (F1 and F2), where a longitudinal follow-up of piglets was performed from birth to 8-12 weeks of age. During the study, a highly virulent isolate of porcine reproductive and respiratory syndrome virus (PRRSV) was introduced on both farms. This allowed us to examine the impact of such introduction on the patterns of infection, disease, and the antibody response of pigs to IAV infection.