Pseudorabies (Aujeszky's Disease)

Pseudorabies, also referred to as Aujeszky's disease, is a viral infection that presents a substantial risk to pig populations on a global scale. The disease is caused by the pseudorabies virus (PRV), which belongs to the family Herpesviridae and the genus Varicellovirus. While its primary impact is on pigs, pseudorabies can also infect various other animals, including dogs, cats, cattle, sheep, and, albeit rarely, humans.

Etiology

PRV is distinguished by its status as a double-stranded DNA virus, featuring a complex structure. This virus swiftly and effectively spreads among pig herds and farms. Its notable resilience in the environment over extended periods poses challenges to eradication. PRV predominantly spreads through direct contact with infected animals, inhalation of respiratory secretions, or the ingestion of contaminated substances.

Fig. 1 Schematic representation of the structure of the pseudorabies virus capsid.¹

Effects and Pathogenesis

Pseudorabies impacts pigs across all age groups, although the severity varies based on the age and immune status of the animals. In younger pigs, the disease can be fatal, while older pigs tend to exhibit milder clinical signs. The pathogenesis of pseudorabies involves the virus entering the body through the respiratory tract or mucous membranes, replicating in the tonsils, and spreading to the nervous system and other organs. Clinical manifestations of the disease may include respiratory distress, neurological disorders, reproductive issues, and, in severe cases, mortality.

Fig. 2 Pathogenesis of pseudorabies virus and damage to different organs in pigs.²

Signs and Symptoms

Respiratory symptoms, including coughing, sneezing, and runny nose, are usually observed in pigs infected with pseudorabies. Neurologic symptoms such as ataxia, tremors, and seizures may also occur. In sows, pseudorabies can lead to reproductive failure including abortion, stillbirth, and weak piglets. Other signs may include fever, loss of appetite, and skin lesions.

Nonporcine species may exhibit various clinical signs when affected by rotavirus. These signs can include sudden death, intense local itching, central nervous system (CNS) symptoms such as circling, abnormal behavior, and paralysis, as well as fever and respiratory distress.

Diagnosis

Timely and accurate diagnosis of pseudorabies is critical for disease management and control. BioVenic develops various diagnostic solutions for customers to confirm the presence of the pseudorabies virus or to detect specific antibodies.

• Veterinary Molecular Diagnostics
  
  • PCR
  • NGS
• Veterinary Immunodiagnostics
  
  • ELISA
  • Virus Neutralization Assay
  • Serum Plate Agglutination Assay, etc.

Additionally, thorough clinical examination, history, and post-mortem analysis can provide valuable insights.

Treatment and Prevention

Pseudorabies stands as a significant menace to pig health and production. Regrettably, there is currently no specific antiviral treatment available for porcine pseudorabies. Therefore, prevention and control measures are essential for the effective control of pseudorabies. As an experienced animal diagnostics company, we have unique insights into the prevention of the disease, providing customers with comprehensive prevention and control measures, including the development of the pseudorabies vaccine.

• Vaccination
  
  • We recommend vaccination against pseudorabies, either live attenuated or inactivated, for pigs of all ages.
  • Intranasal immunization of sows and newborn piglets aged 1-7 days.
  • Other pigs were vaccinated intramuscularly.
  • The breeding herd was vaccinated quarterly.
  • At 14 weeks of age, finishing pigs are administered vaccinations following the decline of maternal antibody levels.
• Biosecurity Measures
  
  • Enact strict quarantine measures
  • Regular monitoring of PRV
  • Implement animal movement control and disinfection procedures
  • Stock, embryos, and semen must be disease-free
  • Once the disease occurs, the group will be eliminated
  • Disinfect contaminated pens or leave them vacant for 10-12 weeks.

BioVenic has been working to gain a deeper understanding of the causes, consequences, and diagnosis of pseudorabies. We are committed to mitigating the impact of pseudorabies through a multifaceted approach, including the development of diagnostics solutions and vaccines, and biosafety protocols. If our services meet your requirements, please feel free to contact us.

References

1. Wang, Guosong, et al. "Structures of pseudorabies virus capsids." Nature Communications 13.1 (2022): 1533.
2. Zheng, Hui-Hua, et al. "Pseudorabies virus: From pathogenesis to prevention strategies." Viruses 14.8 (2022): 1638.