Mucosal vaccination with recombinant poxvirus vaccines protects ferrets against symptomatic CDV infection

摘要

Canine distemper virus (CDV) infection of ferrets causes a disease characterized by fever, erythema, conjunctivitis and leukocytopenia, similar clinically to measles except for the fatal neurological sequelae of CDV. Juvenile ferrets were vaccinatedtwice at 4-week intervals by the intranasal or intraduodenal route with attenuated vaccinia (NYVAC) or canary-pox virus (ALVAC) constructs containing the CDV haemagglutinin and fusion genes. Controls were vaccinated with the same vectors expressing rabies glycoprotein. Animals were challenged intranasally 4 weeks after the second vaccination with virulent CDV. Body weights, white blood cell (WBC) counts and temperatures were monitored and ferrets were observed daily for clinical signs of infection. WBCs were assayed for the presence of viral RNA by RT-PCR. Intranasally vaccinated animals survived challenge with no virological or clinical evidence of infection. Vaccination by the intraduodenal route did not provide complete protection. All control animals developed typical distemper. Ferrets can be effectively protected against distemper by mucosal vaccination with poxvirus vaccines.