Induced latency in pseudorabies vaccinated pigs
Summary
Even vaccinated pigs can develop latent pseudorabies virus infections. This study found that virulent virus persisted in vaccinated pigs, potentially explaining why vaccination fails to eliminate pseudorabies virus spread in herds.
Area of Science:
- Veterinary Virology
- Immunology
Background:
- Pseudorabies virus (PRV) poses a significant threat to swine health and the global pork industry.
- Current vaccination strategies using modified-live PRV vaccines aim to prevent clinical disease but may not fully eliminate latent infections.
Purpose of the Study:
- To investigate the persistence of latent pseudorabies virus in vaccinated pigs.
- To determine if vaccination prevents viral shedding from latent infections.
Main Methods:
- Pigs were vaccinated with a modified-live PRV vaccine.
- Vaccinated pigs were challenged with a virulent PRV strain.
- Dexamethasone was administered to induce reactivation of latent infection.
- Virus recovery from tonsils and lungs was performed three months post-challenge.
Main Results:
- Vaccinated pigs developed high antibody titers against PRV.
- Despite vaccination and high antibody levels, latent PRV was recovered from tonsils and lungs of dexamethasone-treated pigs.
- This indicates that vaccination did not prevent the establishment of latent infection or subsequent viral shedding.
Conclusions:
- Modified-live PRV vaccination may not prevent the establishment of latent infections in pigs.
- Latent PRV infections can persist in vaccinated animals and may be reactivated.
- These findings highlight challenges in eradicating PRV from vaccinated herds and suggest a need for improved control strategies.
