Vaccines in control of infectious diseases of swine

The study presents data concerning vaccines registered in the EU that are used in the prevention and control of viral and bacterial infectious diseases of swine in Poland. It discusses novel vaccines against infectious diseases of swine, such as ileitis, influenza A virus, and mycoplasmal pneumonia. The advantages of intradermal administration of selected vaccines against certain diseases are discussed. Selected problems regarding the efficacy of vaccination against influenza A virus and PRRS are underlined. The study points out that the efficacy of immunization with inactivated vaccines against PRRS is limited. This, however, may also be true of live vaccines against PRRS, since results of immunization with some live attenuated vaccines can be unsatisfactory as well. It is explained by the fact that there are relatively frequent genetic changes in the genome of the field PRRSV strains, unlike in the virus strain or strains used in the vaccine. Strategies to optimize the use of currently available vaccines against influenza A virus (IAV) are discussed. It is worth noting the high efficacy of the vaccine containing antigens of subtypes H1N1, H3N2, and H1N1 against influenza A virus. Vaccination against IAV induces the production of neutralizing antibodies and protection with a very similar strain. As far as vaccines against viral diseases of swine (pseudorabies, classical swine fever) are concerned, the marker vaccines appear to be very useful in differentiating infected animals from vaccinated ones (DIVA strategy). At the beginning of the 21st century, several new effective vaccines were developed, produced, and used against diarrheal diseases of different etiology and, for the first time, against oedema disease, ileitis, and enzootic pneumonia of swine. In view of the growing problem of mixed infections, the study presents several new vaccines containing multiple antigens of one pathogen (serotypes/genotypes) or different pathogens in combination (polyvalent vaccines). The study also discusses the role of the strategy of vaccination depending on the course of the infectious disease, the type of vaccine, as well as the production system of swine.