Downtime for PRRSv+Myco

Pitkin A, Otake S, Dee S. A one-night downtime period prevents the spread of porcine reproductive and respiratory syndrome virus and Mycoplasma hyopneumoniae by personnel and fomites (boots and coveralls). J Swine Health Prod. 2011;19(6):345–348.

Summary

This paper summarizes observations recorded over a 4-year (1438-day) period regarding the ability of a 1-night period of downtime [+ shower and cloth-change] to prevent mechanical spread of porcine repro- ductive and respiratory syndrome virus and Mycoplasma hyopneumoniae between pig populations by personnel and fomites.

Keywords: swine, porcine reproductive and respiratory syndrome, downtime, personnel, fomites

Effect of PRRSv vaccine on the shedding of wild-type virus from an infected population of growing pigs

Linhares D C, Cano J P, Wetzell T, Nerem J, Torremorell M, Dee S A. Effect of modified-live porcine reproductive and respiratory syndrome virus (PRRSv) vaccine on the shedding of wild-type virus from an infected population of growing pigs. Vaccine 2011 [in press]

Abstract

There are ongoing efforts to eliminate porcine reproductive and respiratory syndrome virus (PRRSv) from regions in the United States swine industry. However, an important challenge for the accomplishment of those efforts is the re-infection of pig units due to the area spread of PRRSv. The objective of this study was to evaluate the effect of PRRS modified-live virus vaccine (MLV) on viral shedding and on dynamics of PRRSv infection in pig populations raised under commercial conditions. The study composed of two rooms of 1000 pigs each. Ten percent of pigs of each room were inoculated with a field isolate of PRRSv. Rooms had separate air spaces and strict scientifically validated biosecurity protocols were adopted to avoid movement of pathogens between rooms. At 8 and 36dpi (days post inoculation), all pigs of the challenge-vaccine group were inoculated with a MLV vaccine. Pigs of the challenge-control group were placebo-inoculated. Blood and oral fluid samples were collected from each room at 0, 8, 36, 70, 96 and 118dpi for PRRSv RNA detection using PCR. PRRSv-antibodies were also screened from blood serum samples with a commercially available ELISA test. Additionally, tonsil scraping samples were collected from both groups at 70, 96 and 118dpi. Moreover, air samples were collected 6 times per week from 0 to 118dpi and were tested for PRRSv RNA using qPCR assay. There was no difference in the PRRSv infection dynamics measured as duration and magnitude of viremia and seroconversion. Also, there was no difference in the frequency of tonsil scraping samples PRRSv-positive by PCR. However, the challenge-vaccine group had significantly less PRRSv shed compared to the challenge-control group. The challenge-vaccine group had significant less PRRSv-positive oral fluids at 36dpi. Moreover, the challenge-vaccine group had significant reduction in the cumulative PRRSv shed in the air.

Copyright © 2011. Published by Elsevier Ltd.

PMID:

 

22063389

 

[PubMed]