Open Access Highly Accessed Case report

One family cluster of avian influenza A(H7N9) virus infection in Shandong, China

Ti Liu1, Zhenqiang Bi1, Xianjun Wang1, Zhong Li1, Shujun Ding1, Zhenwang Bi1, Liansen Wang1, Yaowen Pei1, Shaoxia Song1, Shengyang Zhang1, Jianxing Wang1, Dapeng Sun1, Bo Pang1, Lin Sun1, Xiaolin Jiang1, Jie Lei1, Qun Yuan1, Zengqiang Kou1, Bin Yang1, Yuelong Shu2, Lei Yang2, Xiyan Li2, Kaishun Lu3, Jun Liu3, Tao Zhang3 and Aiqiang Xu1*

  • * Corresponding author: Aiqiang Xu

  • † Equal contributors

Author Affiliations

1 Shandong Provincial Center for Disease Control and Prevention; Shandong Provincial Key Laboratory of Infectious Diseases Control and Prevention, Academy of Preventive Medicine, Shandong University, Jinan 250014, Shandong, China

2 National Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China

3 Zaozhuang Center for Disease Control and Prevention, Zaozhuang, Shandong, China

For all author emails, please log on.

BMC Infectious Diseases 2014, 14:98  doi:10.1186/1471-2334-14-98

Published: 21 February 2014



The first case of human infection with avian influenza A (H7N9) virus was identified in March, 2013 and the new H7N9 virus infected 134 patients and killed 45 people in China as of September 30, 2013. Family clusters with confirmed or suspected the new H7N9 virus infection were previously reported, but the family cluster of H7N9 virus infection in Shandong Province was first reported.

Case presentation

A 36-year-old man was admitted to Zaozhuang City Hospital with progressive respiratory distress and suspicion of impending acute respiratory distress syndrome on April 21. The chest radiography revealed bilateral ground-glass opacities and pulmonary lesions. The second case, the first case’s 4 year old son, was admitted to the same hospital on April 28 with fever and multiple patchy shadows in the bilateral lungs. Both of the two cases were confirmed to infect with H7N9 virus by the results of real-time reverse transcriptase-polymerase-chain reaction (rRT-PCR), virus isolation and serum antibody titer. At the same time, one environment samples was detected positive for H7N9 virus in the living poultry market in Zaozhuang. The homologous analysis of the full genome sequence indicated that both viruses from the patients were almost genetically identical. The field epidemiology investigation showed that the two cases had no recognized exposure to poultry, but had the exposure to the environment. The second case had substantial unprotected close exposure to his ill father and developed symptoms seven days after his last contact with his father. After surgery, the index case and his son were discharged on May 16 and May 6, respectively. 11 close contacts of both patients were identified and tested negative both the throat swabs and the serum antibody.


The infection of the index case probably resulted from contact with environmentally contaminated material. For the son, the probable infection source was from the index case during unprotected exposure, but the possibility from the environment or other sources could not be completely ruled out.

Avian Influenza A (H7N9) virus; Epidemiology; Infectious source