COMPARATIVE ANALYSIS OF PATHOGENICITY OF INFLUENZA A(H5N1) AND A(H1N1)pdm09 VIRUSES IN MICE

Aim. Compare the degree of pathogenicity of newly emerging influenza virus strains with pandemic potential by experimental infection of BALB/c mice with highly pathogenic avian influenza A(H5N1) virus and mouse adapted pandemic influenza A(H1N1)pdm09 virus. Materials and methods. The first group of BALB/c mice (n=24) were infected with highly pathogenic avian influenza A(H5N1) virus in a dose of 5 LD50, and the second group (n=24) were infected with mouse adapted pandemic influenza A(H1N1)pdm09 virus at a dose of 5 LD50. Determination of LD50 and TCID50 were performed by virological methods. Morphological changes in internal organs (lung, brain, liver, kidney, spleen) were examined by light and transmission electron microscopy. Results. Virologic analysis showed that both strains are highly lethal for mice. Microscopic examination revealed the development of interstitial pneumonia in the lungs and generalization of infection in the internal organs. Conclusion. In both groups of BALB/c mice experimentally infected with highly pathogenic avian influenza A(H5N1) and mouse adapted pandemic influenza A(H1N1)pdm09 virus were revealed the development of a highly lethal disease in the form of respiratory pneumonia. It is noted, different mechanisms of pathological process: in case of infection with mouse adapted pandemic influenza A(H1N1)pdm09 virus firstly developed bronchitis, which quickly exacerbated by the development of alveolitis, while in case of infection with highly pathogenic avian influenza A(H5N1) immediately developed alveolitis. On the 6th day after infection recorded the development of generalized infection in mice of both experimental groups