Independence of Evolutionary and Mutational Rates after Transmission of Avian Influenza Viruses to Swine

AUTOR(ES)

Stech, J.

FONTE

American Society for Microbiology

RESUMO

In 1979, an H1N1 avian influenza virus crossed the species barrier, establishing a new lineage in European swine. Because there is no direct or serologic evidence of previous H1N1 strains in these pigs, these isolates provide a model for studying early evolution of influenza viruses. The evolutionary rates of both the coding and noncoding changes of the H1N1 swine strains are higher than those of human and classic swine influenza A viruses. In addition, early H1N1 swine isolates show a marked plaque heterogeneity that consistently appears after a few passages. The presence of a mutator mutation was postulated (C. Scholtissek, S. Ludwig, and W. M. Fitch, Arch. Virol. 131:237–250, 1993) to account for these observations and the successful establishment of an avian H1N1 strain in swine. To address this question, we calculated the mutation rates of A/Mallard/New York/6750/78 (H2N2) and A/Swine/Germany/2/81 (H1N1) by using the frequency of amantadine-resistant mutants. To account for the inherent variability of estimated mutation rates, we used a probabilistic model for the statistical analysis. The resulting estimated mutation rates of the two strains were not significantly different. Therefore, an increased mutation rate due to the presence of a mutator mutation is unlikely to have led to the successful introduction of avian H1N1 viruses in European swine.

Documentos Relacionados

• Genetic Reassortment of Avian, Swine, and Human Influenza A Viruses in American Pigs
• Avian-to-human transmission of the PB1 gene of influenza A viruses in the 1957 and 1968 pandemics.
• Protecting Poultry Workers from Exposure to Avian Influenza Viruses
• Selective shedding and congenital transmission of endogenous avian leukosis viruses.
• X-ray structures of H5 avian and H9 swine influenza virus hemagglutinins bound to avian and human receptor analogs