Project Number: 3625-32000-057-00
Project Type: Appropriated

Start Date: Nov 15, 2001
End Date: Nov 14, 2006

Objective:
Determine the relative role of porcine reproductive and respiratory syndrome virus (PRRSV) and its interactions with other swine pathogens in the Porcine Respiratory Disease Complex (PRDC). Identify mechanisms by which PRRSV establishes persistent infection in pigs, study transmission of PRRSV, and study genetic elements that contribute to virulence. Develop improved vaccines that are highly efficacious against PRRSV and other viral pathogens that cause respiratory and/or reproductive disease in swine.

Approach:
Construct multivalent PRRS vaccines (modified live virus, DNA vaccines, and vectored vaccines) and determine their efficacy in preventing the respiratory facet of PRRS in 3-week-old pigs challenged 6 weeks later. Conduct cross-sectional and prospective field studies in herds with chronic PRDC to determine which pathogens are present at different stages of production and to compare results among affected and naive herds. Investigate: the effect of swine age at the time of infection on the duration of virus persistence; the role of chronic PRRSV infections and avian vectors in the transmission of PRRSV to naive herds; Arg151 of the major PRRSV glycoprotein as a marker for an attenuated vaccine and a virulence factor. Continue to cooperate with swine producers and others to identify causes of severe porcine respiratory and reproductive diseases and to develop new and better methods for disease control. Canceled; 08/05/05; IBC# 0272 BSL-2/BSL-2N; Recertified 10/17/06; IBC# 0243 BSL-2/BSL-2N; Recertified 06/08/06; IBC# 0268 BSL-2/BSL-2N; Recertified 07/28/06; IBC# 0273