A Live-Attenuated Chimeric Porcine Circovirus Type 2 (PCV2) Vaccine Is Transmitted to Contact Pigs but Is Not Upregulated by Concurrent Infection with Porcine Parvovirus (PPV) and Porcine Reproductive and Respiratory Syndrome Virus (PRRSV) and Is Efficacious in a PCV2b-PRRSV-PPV Challenge Model

摘要: The live chimeric porcine circovirus type 2 (PCV2) vaccine with the capsid gene of emerging subtype 2b cloned in genomic backbone nonpathogenic PCV1 is attenuated vivo and induces protective immunity against PCV2. To further determine safety efficacy this experimental vaccine, we tested for evidence pig-to-pig transmission by commingling nonvaccinated vaccinated pigs, determined potential upregulation simultaneous vaccination infection parvovirus (PPV) reproductive respiratory syndrome virus (PRRSV), challenging pigs 4 weeks after PCV2b, PRRSV, PPV. Forty-six 21-day-old, PCV2-naive were randomly assigned to one six groups. Twenty-nine 46 challenged PPV at day 28, 8/46 remained nonchallenged served as negative controls, 9/46 controls. All animals necropsied 49. PCV1-PCV2 viremia was detected contact commingled indicating transmission; however, DNA levels low all regardless concurrent infection. Finally, 28 days before challenge resulted significantly (P < 0.05) decreased amounts PCV2 tissues sera reduced macroscopic microscopic lesions. results study indicate that live-attenuated although transmissible remains concurrently infected PRRSV PCV2b when it administered exposure.