Mild Illness in Avian Influenza A(H7N9) Virus–Infected Poultry Worker, Huzhou, China, April 2013

Huakun Lv¹, Jiankang Han¹, Peng Zhang, Ye Lu, Dong Wen, Jian Cai, Shelan Liu, Jimin Sun, Zhao Yu, Heng Zhang, Zhenyu Gong, Enfu Chen, and Zhiping Chen

Author affiliations: Zhejiang Provincial Center for Disease Prevention and Control, Hangzhou, China (H. Lv, Y. Lu, J. Cai, S. Liu, J. Sun, Z. Yu, Z. Gong, E. Chen, Z. Chen); Huzhou Municipal Center for Disease Prevention and Control, Huzhou, China (J. Han, P. Zhang, D. Wen); the 11th Chinese Field Epidemiology Training Program, Beijing, China (H. Zhang)

Abstract

During April 2013 in China, mild respiratory symptoms developed in 1/61 workers who had culled influenza A(H7N9) virus–infected poultry. Laboratory testing confirmed A(H7N9) infection in the worker and showed that the virus persisted longer in sputum than pharyngeal swab samples. Pharyngeal swab samples from the other workers were negative for A(H7N9) virus.

During March–May 2013, a respiratory disease caused by avian influenza A(H7N9) virus was identified among humans in China (1–6). Most infected persons were > 60 years of age, and most cases were severe and involved serious complications, including death (1). Few children and adults have been reported with mild illness caused by influenza A(H7N9) virus infection (7,8). After an epidemiologic link was reported between exposure to poultry and confirmed influenza A(H7N9) cases (9–11), local governments closed contaminated wholesale wet markets (large markets where live chickens were sold to vendors) and assigned government office workers to assist in a temporary poultry culling campaign.
The largest number of confirmed cases was reported in Zhejiang Province, where 46 cases and 11 deaths occurred (data from the Chinese Disease Surveillance Information Report and Management System; as of July 20, 2013). Of the 46 cases, 12 were reported from Huzhou city, where the environment of a wholesale wet market was contaminated by influenza A(H7N9) virus (9). Approximately 25,000 live chickens were processed daily at this market, and on April 8, 2013, the Huzhou city government launched their campaign to close the market and slaughter the remaining poultry.

Figure 1

Thumbnail of Personal protective equipment worn by government workers assigned to cull poultry at a wet market in Huzhou city, Zhejiang Province, China, April 8, 2013. The protective clothing included ordinary disposable masks and latex gloves but not goggles or face shields.

Figure 1. . Personal protective equipment worn by government workers assigned to cull poultry at a wet market in Huzhou city, Zhejiang Province, China, April 8, 2013. The protective clothing included ordinary disposable...

Sixty-one government workers participated for 3 hours in the culling campaign. The workers wore individual personal protective equipment, including protective clothing, ordinary disposable masks, and latex gloves; neither goggles nor face shields were worn (Figure 1). During the culling process, workers disarticulated chickens’ necks and placed the dead birds in individual sacks.
Avian influenza A(H7N9) infection was subsequently confirmed in 1 of the 61 workers. We conducted an epidemiologic investigation and clinical review of the confirmed case. In addition, we administered questionnaires to the 60 co-workers and obtained pharyngeal swab samples from them to test for influenza A(H7N9) virus.