Preliminary Epidemiology of Human Infections with Highly Pathogenic Avian Influenza A(H7N9) Virus, China, 2017

Abstract

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.

Figure 1

Geographic distribution of human cases of infection with HPAI A(H7N9) virus, China, September 1, 2016–March 31, 2017. The red circles indicate the counties with HPAI A(H7N9) virus infections within Guangxi, Guangdong, and Hunan provinces during the fifth epidemic. Shading indicates the total numbers of LPAI A(H7N9) virus infections by province during the fifth epidemic. HPAI, highly pathogenic avian influenza; LPAI, low pathogenic avian influenza.

Figure 2

Human infections with HPAI or LPAI A(H7N9) viruses, by illness onset date, China, September 1, 2016–March 31, 2017. A) Dates of illness onset for the 8 HPAI A(H7N9) cases compared with those for all LPAI A(H7N9) cases. B) Dates of illness onset for the 8 HPAI A(H7N9) cases compared with those for LPAI A(H7N9) cases in 3 provinces (Guangxi, Guangdong, and Hunan).