Zhejiang Province - Credit Wikipedia
# 7899
With remarkable speed, today Chinese scientists published a highly detailed Rapid Communications in the Journal Eurosurveillance on the H7N9 case reported in Zhejiang Province just last week (see Zhejiang Province Reports New H7N9 Case). Among their findings, this latest virus is that this virus is 99.6% identical to the samples isolated last spring, but with 5 new mutations in the virus’s NA (Neuraminidase) gene.
In addition to an overview of the Chinese surveillance system, we get a detailed case description, a discussion of the genetic changes to the virus’s NA gene, and some tantalizing news about serological studies about to be conducted on local residents with exposures to affected live poultry markets and poultry farms.
One notable change from last spring’s pattern – although one case isn’t enough to make any broad assumptions over – is that this case involves an unusually severe illness in a young (mid-30s), previously healthy individual. There is also no obvious live bird or poultry exposure in the 10 days prior to his illness.
Severe cases last spring tended to be skewed towards older patients, predominately male, and usually having co-morbidities. And poultry exposure – while not universal – was a commonly reported.
A link to the study, and some brief excerpts. But you’ll want to read the entire report.
Eurosurveillance, Volume 18, Issue 43, 24 October 2013
Rapid communications
Human infection with avian influenza A(H7N9) virus re-emerges in China in winter 2013
E Chen, Y Chen, L Fu, Z Chen, Z Gong, H Mao, D Wang, M Y Ni, P Wu, Z Yu, T He, Z Li, J Gao, S Liu, Y Shu, B J Cowling, S Xia, H Yu
Citation style for this article: Chen E, Chen Y, Fu L, Chen Z, Gong Z, Mao H, Wang D, Ni MY, Wu P, Yu Z, He T, Li Z, Gao J, Liu S, Shu Y, Cowling BJ, Xia S, Yu H. Human infection with avian influenza A(H7N9) virus re-emerges in China in winter 2013. Euro Surveill. 2013;18(43):pii=20616. Available online: http://www.eurosurveillance.org/ViewArticle.aspx?ArticleId=20616 Date of submission: 18 October 2013
Through a national surveillance system for unexplained pneumonia, a severe case of influenza A(H7N9) in a man in his mid-30s was identified in Zhejiang Province, China on 14 October 2013. Epidemiological and clinical findings were consistent with the patterns reported during the outbreak in spring 2013, and laboratory findings showed that the virus had 99.6% identity with earlier H7N9 viruses identified in humans in the spring except for five mutations in the NA gene.
Case description
A male case in his mid-30s was diagnosed with laboratory-confirmed influenza A(H7N9) virus in Shaoxing City on 14 Oct 2013. His illness began on 7 October. The patient had no smoking history, and had no occupational exposure to poultry. He has been living in Shaoxing city for seven years, sharing with one colleague a dormitory located 1 km away from his daily workplace. The dormitory is located in a village where free-range chickens are kept. The patient did not report any contact with patients with influenza-like illness or visits to live-bird and animals markets within 10 days of illness onset except that he travelled to a neighbouring city on 2–3 October and ate cooked chicken on 6 October.
Illness began with influenza-like symptoms; including cough and 40.5 ºC fever on 7 October. The patient consulted a township hospital twice, on 8 and 9 October. He was first admitted to the township hospital on the morning of 11 October and then transferred to Shaoxing municipality hospital because of progressive dyspnoea and shortness of breath. At midnight on 11 October, his condition deteriorated and he was transferred to the intensive care unit. The patient was reported to Zhejiang CDC as a suspected influenza A(H7N9) case on 14 October. One throat swab was collected on October 14 and tested positive for influenza A(H7N9) with real-time PCR on the same day. The government announced the case on 15 October (Figure 1).
A chest radiograph on 9 October revealed bilateral interstitial pneumonia, and consolidation was noted in a chest computed tomography scan on 11 October. The results of the clinical biomarkers are listed in Table 2. The case was diagnosed as a laboratory-confirmed case of influenza A(H7N9) infection with severe pneumonia combined with two complications: acute respiratory distress syndrome (ARDS) and acute respiratory failure (type I). Treatment with oseltamivir was started at a dose of 150 mg twice daily on 13 October. Endotracheal intubation and mechanical ventilator support (positive end expiratory pressure, PEEP) were given on 11 October because of acute respiratory failure. His condition continued to worsen despite further treatments including oxygen, antibiotic therapy (cefuroxime sodium + levofloxacin lactate + imipenem/cilastatin) and intravenous immunoglobulin therapy (Table 2). As of 24 October, the patient has remained in intensive care and his condition remains serious.
Conclusion
Human infection with influenza A(H7N9) virus has re-emerged in winter 2013, without substantial genetic change in the virus, signalling the potential for a new epidemic wave this winter. It is important to monitor the pandemic potential of this re-emerging virus which has apparently continued to circulate in an animal reservoir during the summer. Based on experiences in the spring, enhanced and expanded surveillance in the human and animal populations help to ensure early discovery and diagnosis of suspected cases, while hygiene campaigns and closure of live poultry markets can reduce the risk of severe cases and deaths. In particular, enhanced surveillance in poultry would be helpful if it can identify the H7N9 virus and inform early control measures before human infections occur. In the longer term, reformation of the poultry farming, distribution and purchasing system may be required to reduce human risk of infection with avian influenza viruses.
This report also contains a brief mention of the second case, reported earlier this week, although few details are available.
