title: [Investigation of a family clustering of human infection with avian influenza A (H7N9) virus in Nanning, Guangxi].
abstract: OBJECTIVE
  To understand the transmission mode of human infection with avian influenza A (H7N9) virus.
  
  
  METHODS
  Field epidemiological investigation was conducted for a family clustering of human infection with H7N9 virus in Hengxian county, Guangxi Zhuang Autonomous Region in February 2014. Two patients and their 82 close contacts were surveyed. The samples collected from the patients, environments and poultry were tested by using real time reverse transcriptase-polymerase chain reaction (rRT-PCR), and the samples from patients were used for virus isolation. The samples from 5 close contacts were tested with RT-PCR. The clinical data, exposure histories of the patients and the detection results of the isolates and their homology were analyzed.
  
  
  RESULTS
  Patient A became ill 4 days after her last exposure to poultry in Zhongshan, Guangdong province, and returned to her hometown in Hengxian 2 days after onset. Patient B was patient A's 5 years old son, who had no known exposure to poultry but slept with patient A for 4 days. He developed symptoms 4 days after last contact with his mother. Two strains of H7N9 virus were isolated from the two patients. The 2 isolates were highly homogenous (almost 100%) indicated by gene sequencing and phylogenetic tree. None of the other 81 close contacts developed symptoms of H7N9 virus infection.
  
  
  CONCLUSIONS
  Patients B was infected through close contact with patient A, indicating that avian H7N9 virus can spread from person to person, but the transmissibility is limited and non-sustainable.
authors.affiliation: Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Nanning 530028, China.
authors.forename: Hai
authors.initials: H
authors.lastname: Li
authors.affiliation: Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Nanning 530028, China; Email: gxlinmei@126.com.
authors.forename: Mei
authors.initials: M
authors.lastname: Lin
authors.affiliation: Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Nanning 530028, China.
authors.forename: Zhenzhu
authors.initials: Z
authors.lastname: Tang
authors.affiliation: Nanning Municipal Center for Disease Control and Prevention.
authors.forename: Xinqin
authors.initials: X
authors.lastname: Lin
authors.affiliation: Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Nanning 530028, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Tan
authors.affiliation: Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Nanning 530028, China.
authors.forename: Minmei
authors.initials: M
authors.lastname: Chen
authors.affiliation: Guangdong Provincial Center for Disease Control and Prevention.
authors.forename: Haojie
authors.initials: H
authors.lastname: Zhong
authors.affiliation: Nanning Municipal Center for Disease Control and Prevention.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Liu
authors.affiliation: Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Nanning 530028, China.
authors.forename: Fuyin
authors.initials: F
authors.lastname: Bi
authors.affiliation: Nanning Municipal Center for Disease Control and Prevention.
authors.forename: Jianyan
authors.initials: J
authors.lastname: Lin
authors.affiliation: Guangxi Zhuang Autonomous Region Center for Disease Control and Prevention, Nanning 530028, China.
authors.forename: Shuwu
authors.initials: S
authors.lastname: Zhou
authors.affiliation: Hengxian County Center for Disease Control and Prevention.
authors.forename: Zhuoxin
authors.initials: Z
authors.lastname: Huang
mesh_terms: D000818:Animals; D002675:Child, Preschool; D002681:China; D016000:Cluster Analysis; D016358:Contact Tracing; D005190:Family; D005260:Female; D006720:Homozygote; D006801:Humans; D064766:Influenza A Virus, H7N9 Subtype / Q000235:genetics / Q000302:isolation & purification*; D007251:Influenza, Human / Q000635:transmission* / Q000821:virology*; D008297:Male; D010802:Phylogeny; D011200:Poultry / Q000821:virology; D060888:Real-Time Polymerase Chain Reaction; D012890:Sleep