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torsdag 28 mars 2019

H7N9

 2019
 Avian Influenza Weekly Update Number680|2 
Human infection with avian influenza A(H7N4) virus in China 
Between 8March and 14March 2019, no new casesof human infection with avian influenza A(H7N4) virus were reported to WHO in the Western Pacific Region.To date, only one laboratory-confirmed case of human infection with influenza A(H7N4) virus has been reported to WHO. This case was reportedfromChina on14 February 2018. 


Human infection with avian influenza A(H7N9) virus in China
 Between 8 March and 14 March 2019, no new cases of human infection with avian influenza A(H7N9) virus were reported to WHO in the Western Pacific Region. As of 14 March 2019, a total of 1567 laboratory-confirmed human infections with avian influenza A(H7N9) virus have been reported to WHO since early 2013, including 40 instances of 2-3 person clusters. Included in this total are 32 human cases of HPAI A(H7N9) virus all reported during the 5th wave(1 October 2016 to 30 September 2017).  These 32cases were from Fujian, Guangdong, Guangxi, Hebei, Henan, Hunan, Shaanxi, Taiwan, China(the case had travel history to Guangdong), and Yunnan. No increased transmissibility or virulence of the virus within human cases has been detected related to the HPAI A(H7N9) virus(source).WHO is continuing to assess the epidemiological situation and will conduct further risk assessments as new information becomes available. The number and geographical distribution of human infections with avian influenza A(H7N9) viruses in the fifth epidemic wave (1 October 2016to 30 September 2017) was greater than previous waves and the subsequent sixth wave (1 October 2017 to 30 September 2018). Further sporadic human cases of avian influenza A(H7N9) virusinfection are expected in affected and possibly neighbouring areas. Should human cases from affected areas travel internationally, their infection may be detected in another country during or after arrival. However,if this were to occur, community level spread is considered unlikely as the virus does not have the ability to transmit easily among humans.To date, there is no evidence of sustained human-to-human transmission of avian influenza A(H7N9) virus. Human infections with the A(H7N9) virus are unusual and need to be monitored closely in order to identify changes in the virus and transmission behaviour to humans as this may have serious public health impacts. For more information on human infection with avian influenza A(H7N9) virus reported to WHO: 
http://www.who.int/influenza/human_animal_interface/influenza_h7n9/en/

Avian influenza A(H7N9) virus


Courtesy of WHO Collaborating Centre for Reference and Research on Influenza, National Institute of Infectious Diseases, Japan
Avian influenza A(H7N9) is a subtype of influenza viruses that have been detected in birds in the past. This particular A(H7N9) virus had not previously been seen in either animals or people until it was found in March 2013 in China.

However, since then, infections in both humans and birds have been observed. The disease is of concern because most patients have become severely ill. Most of the cases of human infection with this avian H7N9 virus have reported recent exposure to live poultry or potentially contaminated environments, especially markets where live birds have been sold. This virus does not appear to transmit easily from person to person, and sustained human-to-human transmission has not been reported.

Highlights

1  Influenza at the human-animal interface

 Summary and assessment, 22January to 12 February 2019
 •New infections1:
 Since the previous update on 21 January 2019, two human infections with avian influenza A (H9N2)viruses and one human infection with an influenza A(H3N2) variant viruswere reported. 
•Risk assessment: 
The overall public health risk from currently known influenza viruses at the human-animal interface (HAI)  has not changed, and the likelihood of sustained human-to-human transmission of these viruses remains low. Further human infections with viruses of animal origin are expected. 
 •Risk management:
 Selection of new candidate vaccine viruses (CVVs) for zoonotic influenza for influenza pandemic preparedness purposes was done during a recent WHO consultation.2
 •IHR compliance:All human infections caused by a new influenza subtype are required to be reported under the International Health Regulations (IHR, 2005).3This includes any influenza A virus that has demonstrated the capacity to infect a human and its heamagglutinin gene (or protein) is not a mutated form of those, i.e. A(H1)or A(H3), circulating widely in the human population. Information from these notifications is critical to inform risk assessments for influenza at the human-animal interface.

 Avian Influenza Viruses
 Current situation:  
Avian influenza A(H5) virusesSince the last update on 21January 2019, no new laboratory-confirmed human casesof influenza A(H5) virus infectionswerereported to WHO. According to reports received by the World Organisation for Animal Health (OIE), various influenza A(H5) subtypes continue to be detected in birds in Africa, Europe and Asia. 
Overall, the risk assessment has not changed. 
 Avian influenza A(H7N9) viruses 
Since the last update on 21January2019, no new laboratory-confirmed human cases of influenza A(H7N9) virus infections were reported to WHO. There have been no publicly available reports from animal health authorities in China of influenza A(H7N9) virus detections in animals in recent months.4,5
 Overall, the risk assessment has not changed

Previous situation analysis


 2013


https://www.who.int/influenza/human_animal_interface/influenza_h7n9/H7N9VirusNaming_16Apr13.pdf

 Standardization of the influenza A(H7N9) virus terminology16 April 2013
 Please note that the agreed terminology below will be used for all WHO documents from 17 April 2013 onwards. 
 After broad consultations with experts from FAO, OIE and WHO, a consensus has been reached on the naming of the influenza A(H7N9) virus recently detected in China. The below approach is adopted and will be used in the three organizations’ communications.
 •  The core term is "avian influenza A(H7N9) virus", which will be used for scientific / technical or other reports.
 •The core term will be used but can be further modified according to specific circumstances.
 For example:
 o"human infection (or disease) caused by the avian influenza A(H7N9) virus"
 o"chicken infection (or disease) caused by the avian influenza A(H7N9) virus" 
o"swine infection (or disease) caused by the avian influenza A(H7N9) virus" - if detected in swine 
•For media communications, especially recognizing that social media such as twitter will gravitate towards use of shortest possible terms, it is suggested that terms such as "H7N9", "H7N9 virus" be used as surrogates as needed. 
The above joint standardization efforts from FAO, OIE and WHO are expected to streamline the communication at all levels globally. The three organizations are committed to joint utmost efforts to respond to challenges including terminology under complicated circumstances, and will review and develop a systematic naming approach to address similar and unpredicted events in the future.
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