Genesis of avian-origin H7N9 influenza A viruses

摘要

Since March, 2013, 126 laboratory-confirmed cases of avian influenza A H7N9 have been detected in ten provinces or municipalities in east and southeast China (as of April 30, 2013).1 Most H7N9-infected patients are older (approximate median age 62 years) urban men who reported exposure to chickens or captive-bred pigeons either professionally or through visits to live poultry markets.23 Patients rapidly develop progressive pneumonia leading to acute respiratory distress syndrome and multiorgan failure.4 The case fatality rate seems to be roughly 20%,5 although this early estimated rate will probably prove to be inflated when the denominator increases upon detection of more moderate, mild, or asymptomatic infections through seroepidemiological studies.