Immunogenicity and safety of a livePasteurella anatipestifervaccine in White Pekin ducklings: Laboratory and field trials

Abstract

SUMMARYOral or aerosol administration of a live trivalent Pasteurella anatipestifer (PA) vaccine (serotypes 1, 2 and 5) gave significant protection against homologous challenges in White Pekin ducklings. Vaccination of one-day-old ducklings by either method provided protection for at least 42 days of age (last challenge). The vaccine did not cause any untoward signs or mortality in one-day-old ducklings exposed to ten times the recommended dose.The vaccine strains did not revert to virulence on 10 back-passages. However, they were reisolated from tracheas and sinuses of the contact-exposed ducklings which were also resistant to challenge with homologous serotype. Feeding of chlortetracycline (0.044%) or sulphadimethoxine-ormetoprim (0.02%) for first 2 weeks of age had no adverse effect on efficacy of the vaccine.The vaccine was found to be both safe and efficacious in field trials in which one-day-old ducklings were exposed by aerosol in the hatcher.

Chicken embryo lethality assay for determining the virulence ofRiemerella anatipestiferisolates

“…Twenty-one serotypes have been identified, and the serotypes vary in virulence (Pathanasophon et al, 1995). Several serotypes including 1, 2, and 5 are highly virulent and commonly found in the USA, Denmark, and South Asia such as China and Singapore (Sandhu, 1991;Sandhu & Leister, 1991;Andreasen & Sandhu, 1993). In addition, differences in strain virulence are also observed within a given serotype (Brogden, 1989).…”

“…In addition, differences in strain virulence are also observed within a given serotype (Brogden, 1989). Although serotype 1 has a high mortality rate in most countries, there is an avirulent vaccine strain of this serotype in the USA (Sandhu, 1991). Additionally, R. anatipestifer serotype 4 is commonly distributed in duck groups with 70 to 100% mortality rates in China (Wang et al, 2002).…”

Evaluation of different diagnostic tools for the detection and identification of Riemerella anatipestifer

“…To date, 21 RA serotypes have been classified (Bisgaard, 1982;Sandhu & Leister, 1991;Loh et al, 1992;Pathanasophon et al, 1995Pathanasophon et al, , 2002 and several serologically unclassified strains have been reported, which may further increase the number of serotypes in the near future (Kö hler et al, 1997;Metzner et al, 2008). Cross-protection between the different serotypes is poor (Sandhu, 1979(Sandhu, , 1991Pathanasophon et al, 1996). Thus identification of the predominant RA serotypes circulating in a certain area is necessary for the choice of appropriate RA vaccines.…”

Identification and Characterization of CAMP Cohemolysin as a Potential Virulence Factor of Riemerella anatipestifer

“…An OmpA protein was characterized for its possible use in serodetection of R. anatipestifer infection (28). Inactivated bacterins and live vaccines have successfully conferred protection against homologous strains or serotypes of R. anatipestifer but were unable to protect against heterologous serotype exposure (20,22).…”