Giuseppe
Emeritus
[Source: European Centre for Disease Prevention and Control (ECDC), full PDF document: (LINK). Edited.]
COMMUNICABLE DISEASE THREATS REPORT
Week 19, 5-11 May 2013
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Influenza A(H7N9) - China - Monitoring human cases
Opening date: 31 March 2013 Latest update: 7 May 2013
Epidemiological summary
On 31 March 2013, Chinese authorities announced the identification of a novel reassortant A(H7N9) influenza virus isolated from three unlinked fatal cases of severe respiratory disease in eastern China, two in Shanghai and one in Anhui province. The WHO Collaborating Centre for Reference and Research on Influenza at the Chinese Center for Disease Control and Prevention (CCDC) had subtyped and sequenced the viruses and found to be of almost identical low pathogenic avian origin.
Since 31 March 2013, 131 cases of human infection with influenza A(H7N9) have been reported from eastern China and Taiwan: Zhejiang (46), Shanghai (33), Jiangsu (27), Henan (4), Anhui (4), Beijing (1), Shandong (2), Fujian (5), Hunan (2), Jiangxi (6) and Taiwan (1). In addition, the virus has been detected in one asymptomatic case in Beijing. Onset of disease was between 19 February and 29 April 2013. The date of disease onset is currently unknown for fifteen patients. Most cases have developed severe respiratory disease. Thirty one patients have died (case-fatality ratio=24%). The median age is 61 years ranging between four and 91 years; 37 of 131 patients are female.
The Chinese health authorities are responding to this public health event with enhanced surveillance, epidemiological and laboratory investigation and contact tracing. The animal health sector has intensified investigations into the possible sources and reservoirs of the virus. The authorities reported to the World Organisation for Animal Health (OIE) that avian influenza A(H7N9) was detected in samples from pigeons, chickens and ducks, and in environmental samples from live bird markets ('wet markets') in Shanghai, Jiangsu, Anhui and Zhejiang provinces. Authorities have closed markets and culled poultry in affected areas.
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ECDC assessment
Influenza A(H7N9) is a zoonotic disease that has spread or is spreading in poultry in parts of Eastern China. It is a severe disease to humans because of its lethal effect in around 20% of human cases. At this time there is no evidence of person-to-person transmission. Close to 3 000 contacts have been followed-up and only four are reported to have developed symptoms, as part of three small family clusters.
At present, the most immediate threat to EU citizens is to those in China who are strongly advised to avoid live bird markets. The risk of the disease spreading to Europe via humans in the near future is considered low. However, it is likely that people presenting with severe respiratory infection in the EU and a history of potential exposure in the outbreak area will require investigation in Europe.
There is no specific guidance on blood or tissue donor deferral for exposure to avian influenza. The incubation period for A(H7N9) is assumed to be 10 days or less, and there is no reason to believe that infected people will be viraemic beyond the acute disease episode. Therefore, the risk of transmission through blood transfusion can be considered very low in the context of the current donor selection procedures.
Actions
ECDC is closely monitoring developments and is continuously re-assessing the situation in collaboration with WHO, the US CDC, the Chinese CDC and other partners.
This epidemiological update does not change the conclusions and recommendations of the updated rapid risk assessment published on 12 April 2013. ECDC published an epidemiological update on A(H7N9) on 29 April 2013.
A case detection algorithm and an EU case definition has been developed and shared with EU Member states. The documents will also be published on the ECDC website in the coming days.
ECDC guidance for Supporting diagnostic preparedness for detection of avian influenza A(H7N9) viruses in Europe for laboratories was published on 24 April 2013.
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COMMUNICABLE DISEASE THREATS REPORT
Week 19, 5-11 May 2013
(...)
Influenza A(H7N9) - China - Monitoring human cases
Opening date: 31 March 2013 Latest update: 7 May 2013
Epidemiological summary
On 31 March 2013, Chinese authorities announced the identification of a novel reassortant A(H7N9) influenza virus isolated from three unlinked fatal cases of severe respiratory disease in eastern China, two in Shanghai and one in Anhui province. The WHO Collaborating Centre for Reference and Research on Influenza at the Chinese Center for Disease Control and Prevention (CCDC) had subtyped and sequenced the viruses and found to be of almost identical low pathogenic avian origin.
Since 31 March 2013, 131 cases of human infection with influenza A(H7N9) have been reported from eastern China and Taiwan: Zhejiang (46), Shanghai (33), Jiangsu (27), Henan (4), Anhui (4), Beijing (1), Shandong (2), Fujian (5), Hunan (2), Jiangxi (6) and Taiwan (1). In addition, the virus has been detected in one asymptomatic case in Beijing. Onset of disease was between 19 February and 29 April 2013. The date of disease onset is currently unknown for fifteen patients. Most cases have developed severe respiratory disease. Thirty one patients have died (case-fatality ratio=24%). The median age is 61 years ranging between four and 91 years; 37 of 131 patients are female.
The Chinese health authorities are responding to this public health event with enhanced surveillance, epidemiological and laboratory investigation and contact tracing. The animal health sector has intensified investigations into the possible sources and reservoirs of the virus. The authorities reported to the World Organisation for Animal Health (OIE) that avian influenza A(H7N9) was detected in samples from pigeons, chickens and ducks, and in environmental samples from live bird markets ('wet markets') in Shanghai, Jiangsu, Anhui and Zhejiang provinces. Authorities have closed markets and culled poultry in affected areas.
(?)
ECDC assessment
Influenza A(H7N9) is a zoonotic disease that has spread or is spreading in poultry in parts of Eastern China. It is a severe disease to humans because of its lethal effect in around 20% of human cases. At this time there is no evidence of person-to-person transmission. Close to 3 000 contacts have been followed-up and only four are reported to have developed symptoms, as part of three small family clusters.
At present, the most immediate threat to EU citizens is to those in China who are strongly advised to avoid live bird markets. The risk of the disease spreading to Europe via humans in the near future is considered low. However, it is likely that people presenting with severe respiratory infection in the EU and a history of potential exposure in the outbreak area will require investigation in Europe.
There is no specific guidance on blood or tissue donor deferral for exposure to avian influenza. The incubation period for A(H7N9) is assumed to be 10 days or less, and there is no reason to believe that infected people will be viraemic beyond the acute disease episode. Therefore, the risk of transmission through blood transfusion can be considered very low in the context of the current donor selection procedures.
Actions
ECDC is closely monitoring developments and is continuously re-assessing the situation in collaboration with WHO, the US CDC, the Chinese CDC and other partners.
This epidemiological update does not change the conclusions and recommendations of the updated rapid risk assessment published on 12 April 2013. ECDC published an epidemiological update on A(H7N9) on 29 April 2013.
A case detection algorithm and an EU case definition has been developed and shared with EU Member states. The documents will also be published on the ECDC website in the coming days.
ECDC guidance for Supporting diagnostic preparedness for detection of avian influenza A(H7N9) viruses in Europe for laboratories was published on 24 April 2013.
(?)
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