Department of Acute Infectious Disease Control and Prevention, Jiangsu Province Center for Disease Control and Prevention, Nanjing, Jiangsu 210009, China.
BMJ. 2013 Aug 6;347:f4752. doi: 10.1136/bmj.f4752.
To determine whether the novel avian influenza H7N9 virus can transmit from person to person and its efficiency.
Epidemiological investigations conducted after a family cluster of two patients with avian H7N9 in March 2013.
Wuxi, Eastern China.
Two patients, their close contacts, and relevant environments. Samples from the patients and environments were collected and tested by real time reverse transcriptase-polymerase chain reaction (rRT-PCR), viral culture, and haemagglutination inhibition assay. Any contacts who became ill had samples tested for avian H7N9 by rRT-PCR. Paired serum samples were obtained from contacts for serological testing by haemagglutination inhibition assays.
Clinical data, history of exposure before the onset of illnesses, and results of laboratory testing of pathogens and further analysis of sequences and phylogenetic tree to isolated strains.
The index patient became ill five to six days after his last exposure to poultry. The second patient, his daughter aged 32, who provided unprotected bedside care in the hospital, had no known exposure to poultry. She developed symptoms six days after her last contact with her father. Two strains were isolated successfully from the two patients. Genome sequence and analyses of phylogenetic trees showed that both viruses were almost genetically identical. Forty three close contacts of both patients were identified. One had mild illness but had negative results for avian H7N9 by rRT-PCR. All 43 close contacts tested negative for haemagglutination inhibition antibodies specific for avian H7N9.
The infection of the daughter probably resulted from contact with her father (the index patient) during unprotected exposure, suggesting that in this cluster the virus was able to transmit from person to person. The transmissibility was limited and non-sustainable.
确定新型甲型 H7N9 流感病毒是否具有人际传播能力及其效率。
2013 年 3 月对两例人感染甲型 H7N9 禽流感家庭聚集性病例进行的流行病学调查。
中国东部的无锡市。
两名患者、其密切接触者及相关环境。采集患者及环境样本，应用实时逆转录聚合酶链反应（rRT-PCR）、病毒培养和血凝抑制试验进行检测。对出现症状的任何接触者应用 rRT-PCR 检测甲型 H7N9。采集接触者配对血清样本，应用血凝抑制试验进行血清学检测。
临床数据、发病前的接触史、病原体的实验室检测结果及对分离株序列和系统进化树的进一步分析。
首发病例在最后一次接触禽类后 5 至 6 天发病，第二例患者为其 32 岁的女儿，曾在医院为其提供无保护的床边护理，但无明确禽类接触史。她在最后一次与父亲接触 6 天后出现症状。从两名患者中成功分离出两株病毒。基因组序列和系统进化树分析表明，两株病毒几乎完全相同。共确定了 43 名两名患者的密切接触者，其中 1 人出现轻症，但 rRT-PCR 检测甲型 H7N9 病毒结果为阴性。对 43 名密切接触者进行的血凝抑制抗体检测均为甲型 H7N9 病毒阴性。
女儿的感染可能是由于在无保护的情况下与父亲（首发病例）接触所致，提示在此次聚集性疫情中病毒能够在人际间传播。传播能力有限且不可持续。
