Porcine reproductive and respiratory syndrome (PRRS)

1. Introduction

Brief history
Agent
Structure

• Small
• Enveloped
• Shape
• Single strand RNA
• Nine open read fragments
• (ORFs 1a, 1b, 2, 2b, 3, 4, 5, 6, and 7)

2. Economic impact
Economic impact of PRRS

3. Clinical signs
Clinical signs of PRRS

• General clinical signs
• Reproductive clinical signs
• Respiratory clinical signs

4. Pathogenesis
Tissue tropism
Lesions

• Lung
• Lymph nodes
• Other lesions

5. Epidemiology
PRRSv epidemiologic characteristics

• Highly infectious
• Low transmission potential

Incubation time
Routes of transmission
Persistent infections
Mutations and quasispecies
Subpopulations

6. Immunity
Introduction
Innate immunity

• Definitions

Adaptive cell-mediated immunity
Humoral immunity
Maternal immunity
Cross-protection

7. Diagnostic tests
Agent detection

• Best samples
• Histopathology
• Virus isolation (VI)
• Polymerase chain reaction (PCR)
• Direct fluorescent antibody test (FA)
• Immunohistochemistry (IHC)
• Genetic sequencing
• Restriction fragment length polymorphism
• (RFLP)

Antibody detection

• Enzyme-linked immunosorbent assay (ELISA)
• Serum virus neutralization (SVN or SN)
• Indirect fluorescent antibody assay (IFA)
• Immunoperoxidase monolayer assay (IPMA)

8. Herd monitoring
Monitoring program design

• Serum
• Oral fluids
• Herd classification
• Important notes regarding breeding herd
• classification

9. Biosecurity
PRRSv resistance in the environment

• Environmental stability
• Water and manure
• Pork meat
• Vectors

Biosecurity practices
PADRAP

10. Control and elimination
Role of vaccines

• Killed vaccines
• Modified live virus (MLV) vaccines

Basics of control

• McRebel program
• Herd closure
• Homogenize

PrRsv elimination

• AASV position statement regarding PRRS
• Depopulation and repopulation (depop-repop)
• Test and removal
• Herd rollover
• Regional elimination