We compared the characteristics of cases of highly pathogenic avian influenza (HPAI) and low pathogenic avian influenza (LPAI) A(H7N9) virus infections in China. HPAI A(H7N9) case-patients were more likely to have had exposure to sick and dead poultry in rural areas and were hospitalized earlier than were LPAI A(H7N9) case-patients.
Keywords: China; H7N9; HPAI; LPAI; epidemiologic characteristics; epidemiology; highly pathogenic avian influenza; infectious diseases; influenza; respiratory infections; viruses; zoonoses.