Vaccination of swine against H3N2-influenza field isolates using the human Philippines-strain.
Intratracheal inoculation of 2 Belgian H3N2-influenza viral strains, isolated from sick swine in the field, caused high fever, anorexia and dyspnoea in unvaccinated swine. The strains are related to the human A/Port Chalmers/1/73 (H3N2)-strain. In a limited study, 2 subunit vaccines, both derived from the human A/Philippines/2/82 (H3N2)-strain, were tested for efficacy in protecting swine against these Belgian field isolates. Vaccine A was a commercial vaccine, vaccine B an experimental vaccine. For evaluation of the efficacy of the vaccines, clinical as well as virological parameters were used. It was found that 2 spaced injections of the experimental vaccine (B) resulted in very high serum hemagglutination-inhibition (HI) titres against the Philippines-strain. Nevertheless, only partial protection was obtained, as indicated by the milder clinical signs and the decreased viral replication at challenge. One injection of the experimental vaccine (B) and 2 spaced injections of the commercial vaccine (A) did not result in any protection at challenge, even though moderate HI titres against the Philippines-strain were obtained. It was concluded that if an H3N2-strain is included in vaccines for use in swine, a strain should be selected which is identical or very closely related to the strain(s) prevalent in the swine population of the country in which the vaccine will be used.
D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis*; D005455:Fluorescent Antibody Technique; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D053122:Influenza A Virus, H3N2 Subtype; D009980:Influenza A virus / Q000276:immunology*; D007252:Influenza Vaccines / Q000276:immunology*; D009976:Orthomyxoviridae Infections / Q000276:immunology / Q000662:veterinary*; D013552:Swine; D013553:Swine Diseases / Q000276:immunology*; D014611:Vaccination / Q000662:veterinary
D000914:Antibodies, Viral; D007252:Influenza Vaccines