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Comparison of live avirulent M-9, Minnesota, and CU fowl cholera vaccines
R C Friedlander1, L D Olson, E L McCune
1Department of Veterinary Pathology, College of Veterinary Medicine, University of Missouri, Columbia 65211.
Abstract:
The M-9 and Minnesota (MN) avirulent Pasteurella multocida vaccines were evaluated and compared with the Clemson University (CU) vaccine, which had been shown to be highly effective in preventing fowl cholera in turkeys. Neither the M-9 nor the MN vaccine given in the drinking water was as effective as the CU vaccine in protecting turkeys against challenge with virulent P. multocida. When grown in brain-heart infusion (BHI) agar as recommended, the M-9 was not as efficacious as when it was grown in BHI broth. The M-9 was as effective as the CU vaccine only when grown in BHI broth and given at 10 times the standard dosage. Injection of the M-9 vaccine into the air spaces of the head at a site near the caudal rim of the ear after one vaccination in the drinking water was not as effective for hyperimmunizing potential breeders as was the CU vaccine injected at the same site. A microtiter agglutination test demonstrated a significant (P less than 0.05) correlation between the level of anti-P. multocida antibody found 1 week after vaccination and survival after challenge with virulent P. multocida.
Insights
The M-9 and Minnesota (MN) Pasteurella multocida vaccines were less effective than the Clemson University (CU) vaccine for preventing fowl cholera in turkeys. Vaccine efficacy depended on growth medium and dosage, with a correlation between antibody levels and survival.
Area of Science:
- Veterinary immunology
- Avian pathology
- Bacteriology
Background:
- Fowl cholera, caused by Pasteurella multocida, is a significant disease in turkeys.
- The Clemson University (CU) vaccine is recognized for its high efficacy in preventing fowl cholera.
Purpose of the Study:
- To evaluate and compare the efficacy of M-9 and Minnesota (MN) avirulent Pasteurella multocida vaccines against the CU vaccine.
- To determine the impact of vaccine preparation and administration methods on efficacy.
Main Methods:
- Turkeys were vaccinated with M-9 or MN vaccines via drinking water and compared to CU vaccine.
- Vaccine efficacy was assessed by challenging turkeys with virulent P. multocida.
- M-9 vaccine efficacy was tested using different growth media (BHI agar vs. broth) and dosages.
- Booster injections into head air spaces were evaluated for hyperimmunization.
- A microtiter agglutination test measured anti-P. multocida antibody levels.
Main Results:
- Neither M-9 nor MN vaccines in drinking water were as effective as the CU vaccine.
- M-9 vaccine efficacy was reduced when grown on BHI agar compared to BHI broth.
- M-9 vaccine matched CU vaccine efficacy only when grown in broth at 10x the standard dose.
- Injection of M-9 vaccine into head air spaces was less effective for hyperimmunization than CU vaccine.
- A significant correlation (P < 0.05) was found between antibody levels and survival post-challenge.
Conclusions:
- The CU vaccine demonstrated superior efficacy in protecting turkeys against fowl cholera compared to M-9 and MN vaccines.
- Vaccine preparation (growth medium) and administration route significantly influence Pasteurella multocida vaccine efficacy.
- Antibody level is a reliable indicator of protection against virulent P. multocida challenge.