Avian Influenza A (H7N9) Virus

Abstract

The first report of H7N9 avian influenza virus infection in humans occurred in March 2013 in the People Republic of China. Since its first identification, the virus widely spread and resulted in a higher number of patients in many regions. Currently, the disease is still limited to China and the patients who had a history of traveling to the epidemic areas in China. The H7N9 virus is more efficient than the H5N1 avian influenza virus for human infections. The clinical symptoms of H7N9 avian influenza may vary from influenza-like illness, severe pneumonia and acute respiratory distress syndrome, and death with the fatality rate of about 39%. Oseltamivir and zanamivir are effective anti-viral drugs if prescribed early. During the fifth epidemic wave of H7N9 avian influenza, the original virus has changed from being the low pathogenic avian influenza (LPAI) strain to be the highly pathogenic avian influenza (HPAI) strain according to insertion of multiple basic amino acids into the hemagglutinin cleavage site. Since then, both H7N9 LPAI and HPAI viruses co-circulate, and China have entered the seventh epidemic wave at present. The H7N9 virus has not been detected in Thailand yet. Nevertheless, some factors made Thailand at risk for the H7N9 viral spread. The health personnel should know and understand about the H7N9 virus and disease in order to strengthen and prepare Thailand to promptly respond and control the H7N9 outbreak situation, if occur in the future.