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Influenza A(H7N9) - China - Monitoring human cases (ECDC/CDTR, January 24 2014): risk of increased h2h transmission isn't negligible
[Source: European Centre for Disease Prevention and Control (ECDC), full PDF document: (LINK). Extract.]
COMMUNICABLE DISEASE THREATS REPORT
Week 4, 19-25 January 2014
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Influenza A(H7N9) - China - Monitoring human cases
Opening date: 31 March 2013 Latest update: 16 January 2014
Epidemiological summary
In March 2013, Chinese authorities announced the identification of a novel reassortant A(H7N9) influenza virus in patients in eastern China.
Since then, 225 cases of human infection with influenza A(H7N9) have been reported from:
In addition, the virus has been detected in one asymptomatic case in Beijing.
To date, WHO has acknowledged 219 of these cases and the remaining six cases were reported by local health authorities on 23 January 2014.
Most cases have developed severe respiratory disease. Fifty-five patients have died (case-fatality ratio=24.4%).
Ninety cases have been reported since October 2013. The provinces affected are: Taiwan (1), Hong Kong (3), Zhejiang province (42), Guangdong province (25), Jiangsu province (3), Shanghai (8), Fujian (7) and Guizhou (1).
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ECDC assessment
However, the most likely scenario for China is that this remains a local (but widespread) zoonotic outbreak in which the virus is transmitted sporadically to humans in close contact with the animal reservoir, similar to the influenza A(H5N1) situation.
It is commendable that the Chinese authorities quickly notified the event to WHO under the International Health Regulations. The continued communication of outbreak investigations has facilitated the assessment of the risk to human health from this outbreak in Europe as well as elsewhere. It is essential that this continues.
The first human infection with influenza A(H7N9) virus was identified in March 2013, and this was the first time that human infection with a low pathogenic avian influenza A virus has been associated with a fatal outcome. After a period of several months with only few cases detected, the Chinese authorities have detected new cases with increasing frequency since October 2013.
The recent fatal case of influenza A(H5N1) imported to Canada provides support to the notion that imported cases of influenza A (H7N9) might also be seen in Europe. However, the risk of the disease spreading to Europe via humans in the near future is still considered low. People in the EU presenting with severe respiratory infection and a history of potential exposure in the outbreak area will require careful investigation in Europe.
To date, there is no epidemiological evidence that avian influenza can be transmitted to humans through the consumption of cooked food, notably poultry meat and eggs.
Close monitoring of the outbreak epidemiology, clinical features and the genetic characteristics of the virus will be critical for assessing this risk; instruments like the Influenza Risk Assessment Tool (IRAT) can play a role.
European countries should continue to prepare for the eventuality of future pandemics, including one caused by A(H7N9).
Preparedness activities should include the precautionary development of early human vaccine candidates and increased monitoring of animal influenzas at the animal��human interface.
The risk of influenza A(H7N9) virus being transported to Europe in viraemic poultry through legal trade is negligible. EU regulations do not permit importation of live poultry, day-old chicks and hatching eggs and other birds (captive birds such as parrots, finches and ornamental birds) from China. The only poultry commodities authorised for import from China into the EU are sterilised meat products, heat-treated poultry meat from Shandong, and heat-treated egg products. Given the very heat-labile nature of all influenza viruses, these commodities are not considered to pose a risk of influenza virus transmission to consumers.
The risk of the avian influenza A(H7N9) viruses arriving in Europe with migratory birds cannot be quantified. ECDC and the European Food Safety Authority (EFSA) have performed multiple independent risk assessments in the past regarding avian influenza that also cover pathways for avian influenza A(H7N9). The hypothesis that poultry in the affected area has been infected by wild birds has not been confirmed but neither can it be excluded. Surveillance in wild birds for this novel virus has not been initiated in the EU/EEA.
Actions
The Chinese health authorities continue to respond to this public health event with enhanced surveillance, epidemiological and laboratory investigation including scientific research. ECDC is closely monitoring developments. ECDC published an updated Rapid Risk Assessment on 8 May 2013 and a guidance for Supporting diagnostic preparedness for detection of avian influenza A(H7N9) viruses in Europe for laboratories on 24 April 2013.
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COMMUNICABLE DISEASE THREATS REPORT
Week 4, 19-25 January 2014
(...)
Influenza A(H7N9) - China - Monitoring human cases
Opening date: 31 March 2013 Latest update: 16 January 2014
Epidemiological summary
In March 2013, Chinese authorities announced the identification of a novel reassortant A(H7N9) influenza virus in patients in eastern China.
Since then, 225 cases of human infection with influenza A(H7N9) have been reported from:
- Zhejiang (88 cases),
- Shanghai (42),
- Jiangsu (30),
- Henan (4),
- Anhui (4),
- Beijing (2),
- Shandong (2),
- Fujian (12),
- Hunan (3),
- Jiangxi (5),
- Hebei (1),
- Guizhou (1),
- Guangdong (26),
- Hong Kong (3) and
- Taiwan (2).
In addition, the virus has been detected in one asymptomatic case in Beijing.
To date, WHO has acknowledged 219 of these cases and the remaining six cases were reported by local health authorities on 23 January 2014.
Most cases have developed severe respiratory disease. Fifty-five patients have died (case-fatality ratio=24.4%).
Ninety cases have been reported since October 2013. The provinces affected are: Taiwan (1), Hong Kong (3), Zhejiang province (42), Guangdong province (25), Jiangsu province (3), Shanghai (8), Fujian (7) and Guizhou (1).
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ECDC assessment
The continued and increasing transmission of a novel reassortant avian influenza virus capable of causing severe disease in humans in one of the most densely populated areas in the world is a cause for concern due to the pandemic potential.
However, the most likely scenario for China is that this remains a local (but widespread) zoonotic outbreak in which the virus is transmitted sporadically to humans in close contact with the animal reservoir, similar to the influenza A(H5N1) situation.
It is commendable that the Chinese authorities quickly notified the event to WHO under the International Health Regulations. The continued communication of outbreak investigations has facilitated the assessment of the risk to human health from this outbreak in Europe as well as elsewhere. It is essential that this continues.
The first human infection with influenza A(H7N9) virus was identified in March 2013, and this was the first time that human infection with a low pathogenic avian influenza A virus has been associated with a fatal outcome. After a period of several months with only few cases detected, the Chinese authorities have detected new cases with increasing frequency since October 2013.
This indicates a persistent reservoir and transmission pattern which might have seasonal characteristics.
The recent fatal case of influenza A(H5N1) imported to Canada provides support to the notion that imported cases of influenza A (H7N9) might also be seen in Europe. However, the risk of the disease spreading to Europe via humans in the near future is still considered low. People in the EU presenting with severe respiratory infection and a history of potential exposure in the outbreak area will require careful investigation in Europe.
To date, there is no epidemiological evidence that avian influenza can be transmitted to humans through the consumption of cooked food, notably poultry meat and eggs.
There is insufficient evidence to quantify the risk of influenza A(H7N9) developing into a virus that transmits from human to human, thereby increasing the risk of an influenza pandemic.
Close monitoring of the outbreak epidemiology, clinical features and the genetic characteristics of the virus will be critical for assessing this risk; instruments like the Influenza Risk Assessment Tool (IRAT) can play a role.
The risk of increased transmission of H7N9 viruses between humans is not negligible.
European countries should continue to prepare for the eventuality of future pandemics, including one caused by A(H7N9).
Preparedness activities should include the precautionary development of early human vaccine candidates and increased monitoring of animal influenzas at the animal��human interface.
The risk of influenza A(H7N9) virus being transported to Europe in viraemic poultry through legal trade is negligible. EU regulations do not permit importation of live poultry, day-old chicks and hatching eggs and other birds (captive birds such as parrots, finches and ornamental birds) from China. The only poultry commodities authorised for import from China into the EU are sterilised meat products, heat-treated poultry meat from Shandong, and heat-treated egg products. Given the very heat-labile nature of all influenza viruses, these commodities are not considered to pose a risk of influenza virus transmission to consumers.
The risk of the avian influenza A(H7N9) viruses arriving in Europe with migratory birds cannot be quantified. ECDC and the European Food Safety Authority (EFSA) have performed multiple independent risk assessments in the past regarding avian influenza that also cover pathways for avian influenza A(H7N9). The hypothesis that poultry in the affected area has been infected by wild birds has not been confirmed but neither can it be excluded. Surveillance in wild birds for this novel virus has not been initiated in the EU/EEA.
Actions
The Chinese health authorities continue to respond to this public health event with enhanced surveillance, epidemiological and laboratory investigation including scientific research. ECDC is closely monitoring developments. ECDC published an updated Rapid Risk Assessment on 8 May 2013 and a guidance for Supporting diagnostic preparedness for detection of avian influenza A(H7N9) viruses in Europe for laboratories on 24 April 2013.
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