Porcine Reproductive and Respiratory Syndrome (PRRS) Flashcards
What causes PRRS?
an arteriveridae?
What are the clinical properties of arteriveridae?
- can cause asymptomatic persistent infections
- can cause severe fatal dz
- replicate in macrophages
- MUTATES
What are PRRS virus preferred macrophages to infect?
those in the lung and maternal fetal interface
What are the features of PRRSV?ble
- unstable
- strain variation
- variation in virulence
What are the major subtypes of PRRSV?
Type 1
Type 2
High path PRRSV
What is the epidemiology of PRRS?
- highly infectious
- not highly contagious
- persistent (>100d carrier state)
- not fully cross-protective across stains
- subclinical endemic infection common (low virluence in w. canada)
How is environmental survival of PRRSV?
- poor off host
2. susceptible to drying, disinfection etc
How is PRRSV transmitted?
- vertical (semen, transplacental)
- horizontal (pig to pig, dam to piglet)
- fomites
- aerosol–prevalent in hog dense regions
What is the pathogenesis of PRRS?
- replication in lymphoid tissues
- prolonged viremia—>persistent infection
- predelication for pulmonary alveolar macrophages and pulmonary intravascular macrophages
- intersitial pneumoniae
- cross placenta in late gestation (>d 70). fetal death
What are the clinical reproductive signs of PRRS
- In the pregnant sows can have anorexia, fever, mortality if virulent but more often SUBCLINICAL early farrowing
What are the features of the piglets that are born in premature farrowings due to PRRS?
- weak, liveborn
- persistently viremic
- neonatal scours (nonresponsive to antimicobials)
- elevated preweaning portality
What are the respiratory clinical signs of PRRS?
- dypsnea (thumping)
- cyanosis of extremities
- minimal coughing if pure PRRS
- immunosuppression
What are the clinical signs of high fever disease (high path PRRS)
- high fever
- blotchy congestion skin
- abortions
- high case fatality rate
What is the pathology of high fever disease (high path PRRS)
wide spread hemorrhages and edema, diffuse petechiation, splenic infarcts mixed infections
What is the etiology of high fever disease?
high path PRRSV