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This paper summarizes the current state of knowledge regarding the influence of physical exercise on immunity mechanisms in horses. Results of many studies indicate that exercise has an immunomodulating effect on horses. The immunological reaction depended on the intensity of physical exercise. It was found that moderate (single or cyclical) physical exercise stimulated the immunological system (increased the number and activity of immunological cells), while exhausting physical exercise decreased the efficiency of the innate and adaptive mechanisms of immunity. Epidemiological data confirm that the intensive exercise can increase the incidence of respiratory tract infections in horses, whereas moderate exercise presumably decreases the hazard of infection. In order to minimize the exercise-induced risk of infection, regular vaccinations, monitored training, control and supplementation of diet, reducing the environmental stress and, if necessary, chemo- and immunotherapy were recommended.
Content available Genetyczna odpornosc zwierzat na choroby
Disease resistance of the animals may be improved using both, the conventional (marker assisted selection) and genetic engineering methods. Marker-assisted selection (MAS) can use genetic markers as indices of resistance to diseases. The markers may be devided into exterior traits (e.g. udder and teat conformation – mastitis), determined by serological tests (erythrocyte antigens - leukaemia., MHC antigens - mastitis, leukaemia and tuberculosis in cattle, nematode infection in sheep, Marek's disease in poultry) and molecular analysis of DNA (loci encoding intestinal receptor for K88 and F18 Eschericha coli, MHC genes - mastitis and leukaemia in cattle). Conventional methods should be preferable in improvement of existing resistance mechanisms while the genetic engineering methods (e.g. transgenesis) can be used to introduce into livestock genomes the genes controlling resistance to diseases.
The paper reviews on the characteristic of mast cells and their role in innate and adaptive immunity, also in antibacterial, antiviral and antiparasitic response and allergic and autoimmunological reactions. Moreover, the cooperation of mast cells with dendritic cells, lymphocytes T and B has been discussed.
Special attention in this review is given to published work on genetic, antigenic and pathogenic variations of the virus of porcine reproductive and respiratory syndrome (PRRS) and the potential implications of these properties for vaccine efficacy. Genomic organization of type 1 and type 2 strains of the PRRS virus is presented: the former being the representative of the European strains and the latter of the North American isolates. Among the European isolates 4 subtypes are differentiated. More homogenous are the strains of the Northern American type. Despite very high differences in antigenic properties of both European and North American isolates, it is possible to differentiate them, using serological methods, particularly the immunofluorescence test. The ELISA test proved to be useful in diagnosis of PRRS. However, antigens of the PRRS virus are of no use in the selection of strains for vaccine production. The high degree of variation among PRRS virus isolates is also demonstrated in pathogenic properties. Generally, the heterogeneity of genetic, antigenic and pathogenic properties, being a continuous process, is the explanation for the persistent infections resulting from the selection of mutants that escape neutralizing antibodies or cytotoxic T lymphocytes. Because of the heterogeneity of the mentioned biological properties of the field strains, the immunoprophylactic value of the available vaccines is not high. Better results are obtained when live, attenuated vaccines are used. In relation to this topic the proposition of Mengeling, called SWINE, is presented. The first letter means sensitization of the pig by vaccine injection; the second letter means waiting for more than several weeks until the level of neutralizing antibodies reaches low values; the letter I means immunization; N means neutralization of the virus; the letter E means eradication, in other words the elimination of PRRS. The last step must be supported by biosecurity and additional veterinary measures. Another method of immunoprophylaxis is the vaccination of pigs introduced to a herd using viremic serum of pigs of the same herd, which provides the best homogeneity of immunity and the highest efficacy.
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