Project Number: 3625-32000-109-01
Project Type: Reimbursable

Start Date: Oct 01, 2011
End Date: Apr 01, 2013

Objective:
Examine the pathogenesis of secondary bacterial infections subsequent to porcine reproductive and respiratory syndrome virus (PRRSV) infection and evaluate intervention strategies to prevent or treat such infections.

Approach:
In 2006, large outbreaks of a high morbidity/high mortality disease that became known as "porcine high fever disease" (PHFD) began to occur across China, and in 2007, Vietnam began to experience swine disease outbreaks causing clinically similar signs. The disease is associated with newly-emergent, highly-pathogenic porcine reproductive and respiratory syndrome virus (PRRSV) strains, but in both of these outbreaks other viruses and bacteria were often isolated from clinical cases. Results suggest that the cause of the swine deaths in PHFD is a multifactorial syndrome with PRRSV as a major factor. We will compare 2 Asian isolates of PRRSV obtained from the PHFD outbreaks to high and low virulence isolates of PRRSV obtained from the United States for their alteration of innate immune functions and their ability to predispose to secondary bacterial infections in swine. Subsequently, we will compare several antibiotic regimens for their ability to treat or prevent severe bacterial disease that occurs as a sequela to PRRSV infection.