Preparation and evaluation of Pasteurella multocida vaccines in waterfowl and sandhill cranes

Pasteurella multocida serotype A:1 vaccines were prepared and efficacy tested (protection from challenge) in waterfowl and cranes. Serum antibody responses were measured using an indirect ELISA. The bacterin was a beta-propiolactone-killed whole cell suspension mixed with volume of mineral oil adjuvant (Britol 6NF). There was great variation among species to the bacterin in both survival from challenge and serum antibody levels.;A live streptomycin-dependent (StrD) serotype A:1 P. multocida was prepared by mutagenizing the organism with nitrosoguanidine. The route and number of doses of StrD vaccine had a significant effect on its efficacy and induction of antibody response. Pekin ducks that received a single dose of StrD vaccine orally did not survive challenge and had weak serological responses, however, a booster dose significantly increased the antibody response and provided 100% protection from challenge. By subcutaneous inoculation, both one or two doses of StrD vaccine protected 100% of the ducks.;Pasteurella multocida purified capsular polysaccharide (PCP) and outer membrane proteins (OMP) were emulsified in Freund's incomplete adjuvant and used to vaccinate Pekin ducks. The PCP was a poor immunogen while the OMP was highly efficacious at eliciting antibody response and inducing protection. OMP treated with phenol or a combination of 3 proteolytic enzymes was not immunogenic nor protective, while OMP treatment with a single enzyme or heat elicited a lower antibody response but still provided 100% protection. PAGE analysis of the OMP preparation revealed 6 major and 11 minor proteins bands. The major OMPs were tested for immunogenicity and protection efficacy in Pekin ducks. Only the 39.0 kDa protein induced a significant serological response and protected ducks from challenge. Antibodies to 39.0 kDa OMP of serotype A: 1 P. multocida did not crossreact with OMPs extracted from avian isolates of serotypes A:3, A:4, or A:5 P. multocida.;The results of this study have contributed to our understanding of protective immunity against P. multocida in birds. The finding that a single OMP induced protective immunity makes development of a recombinant live vaccine for wild waterfowl a distinct possibility.