Production testing of antigenicity and immunogenicity of bivalent inactivated vaccine salmonellosis vaccine
Abstract
Scientists of both human and veterinary medicine combine their potential to develop new or improve old instruments in order to rein the problem of foodborne salmonellosis in Ukraine. According to the experience of European poultry industry, the most effective measure for the prevention of avian salmonellosis is total vaccination against salmonellosis of laying hens and breeding birds. In our country, the epizootic situation of salmonellosis of animals and poultry is consistently favorable. At the same moment nearly 90% of foods born Salmonella outbreaks are of poultry and egg products origin. In other words the source of major source of Salmonella agent is avian origin. Currently no vaccines of native origin have been registered in Ukraine. Although there have been numerous attempts to develop a vaccine against avian salmonellosis. The purpose of our work is to evaluate the antigenicity and immunogenicity of the two experimental series of bivalent inactivated emulsified vaccine against avian salmonellosis in production conditions. During the examination of the vaccine in the poultry farm it was found that for 21 days after the re-introduction of the vaccine, the titers of antibodies to the mono-antigens S. Typhimurium, Enteritidis and Gallinarum in the Agglutination Test (AT) and Indirect Hemagglutination Test (IH) were: 1 : 640–1280 to 1 : 2560–5120 respectively. This indicates high antigenicity of the vaccine. No significant difference between the levels of antibodies to Typhimurium and Enteritidis antigens was detected neither in AT nor IH. At the same time the levels of antibodies to mono-antigen Gallinarum were markedly lower in both reactions (1 : 160–1 : 320 – in AT and 1 : 320–1 : 1280 – in IH), but high enough to indicate that the vaccine creates a tense cross-humoral immunity to Salmonella surface antigens of Gallinarum serovar. The results of study of immunogenicity of the vaccine show that the vaccine is highly immunogenic. It means that after control infection of vaccinated hens none of tested Salmonella strains (S. Typhimurium and S. Enteritidis) were isolated from any organs, whereas in the control non-vaccinated group of birds both Salmonella test-strains were isolated from all organs. The obtained results provide a basis for further phases of the vaccine estimating followed by its registration in the prescribed manner.
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