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Biological Health Threat (Human-Animal Infections) – Highly pathogenic Avian influenza

2017/01/26

AVIAN INFLUENZA, HUMAN (13): WHO, HUMAN-ANIMAL INTERFACE
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Published Date: 2017-01-26 15:29:45
Subject: PRO/AH/EDR> Avian influenza, human (13): WHO, human-animal interface
Archive Number: 20170126.4792947

Date: Mon 16 Jan 2016
Source: WHO, Influenza at the Human-Animal Interface (HAI) [edited]

Summary [20 Dec to 16 Jan 2017]
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– New infections: Since the previous update, new human infections with influenza A(H7N2), A(H7N9) and A(H9N2) viruses were reported.

– Risk assessment: The overall public health risk from currently known influenza viruses at the human-animal interface 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.

– IHR compliance: All human infections caused by a new influenza subtype are required to be reported under the International Health Regulations (IHR, 2005).This includes any animal and non-circulating seasonal influenza viruses. Information from these notifications is critical to inform risk assessments for influenza at the human-animal interface.

Avian influenza A(H5) viruses
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Current situation:
Since the last update, no new laboratory-confirmed human cases of influenza A(H5) virus infection were reported to WHO. Influenza A(H5) subtype viruses have the potential to cause disease in humans and thus far, no human cases, other than those with influenza A(H5N1) and A(H5N6) viruses, have been reported 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 West Africa, Europe and Asia. There have also been numerous detections of influenza A(H5N8) viruses in wild birds and domestic poultry in several countries in Africa, Asia and Europe since June 2016. For more information on the background and public health risk of these viruses, please see the WHO assessment of risk associated with influenza A(H5N8) virus.

Avian influenza A(H7N9) viruses
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Current situation:
During this reporting period, China reported 110 laboratory-confirmed human cases of influenza A(H7N9) virus infection to WHO. A total of 106 cases were reported in mainland China, 3 cases were reported in Hong Kong Special Administrative Region (SAR) and another case was reported in Macao SAR. Case details are presented in the table in the Annex of this document. For additional details on these cases and public health interventions, see the Disease Outbreak News.

As of [16 Jan 2017], a total of 918 laboratory-confirmed cases of human infection with avian influenza A(H7N9) viruses, including at least 359 deaths, have been reported to WHO (Figure 2). According to reports received by the Food and Agriculture Organization (FAO) on surveillance activities for avian influenza A(H7N9) viruses in China, positives among virological samples continue to be detected mainly from live bird markets, vendors and some commercial or breeding farms.

Risk Assessment:
1. What is the likelihood that additional human cases of infection with avian influenza A(H7N9) viruses will occur?
Most human cases are exposed to the A(H7N9) virus through contact with infected poultry or contaminated environments, including live poultry markets. Since the virus continues to be detected in animals and environments, further human cases can be expected. Additional sporadic human cases of influenza A(H7N9) in other provinces in China that have not yet reported human cases are also expected.

2. What is the likelihood of human-to-human transmission of avian influenza A(H7N9) viruses?
Even though small clusters of cases have been reported, including those involving healthcare workers, current epidemiological and virological evidence suggests that this virus has not acquired the ability of sustained transmission among humans, thus the likelihood is low.

3. What is the risk of international spread of avian influenza A(H7N9) virus by travellers?
Should infected individuals from affected areas travel internationally, their infection may be detected in another country during travel or after arrival. If this were to occur, further community level spread is considered unlikely as this virus has not acquired the ability to transmit easily among humans.

Avian influenza A(H7N2) viruses
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Current situation:
During this reporting period, the United States of America (USA) reported 1 laboratory confirmed human case of influenza A(H7N2) virus infection to WHO. The likely source of infection in the human was through close contact with ill cats infected with an A(H7N2) virus. The infection resulted in mild illness and the individual has recovered. No human-to-human transmission of the virus has been detected thus far. Cats are not the typical host of avian influenza viruses; however, cats have been infected in the past with such viruses (e.g., different avian influenza viruses, as well as human seasonal influenza viruses).

Risk Assessment:
1. What is the likelihood that additional human cases of infection with avian influenza A(H7N2) viruses will occur?
If the virus continues to circulate and infect cats, and humans are in close contact with infected cats, further human cases would be expected but unusual. The hygiene measures put in place following the detection of this human case have likely had an impact on the transmission of the virus from infected cats to humans.

2. What is the likelihood of human-to-human transmission of avian influenza A(H7N2) viruses?
Current evidence suggests that the likelihood is low. Thus far, there has been no evidence of human-to-human transmission of this virus from this human case. There have been 2 previous human cases of infection with A(H7N2) virus reported in the USA, and no human-to-human transmission was detected in these events. There were several presumed human cases of infection with influenza A(H7N2) in the United Kingdom in 2007 and there was no sustained human-to-human transmission detected in that event.

3. What is the risk of international spread of avian influenza A(H7N2) virus by travellers?
Should infected individuals from affected areas travel internationally, their infection may be detected in another country during travel or after arrival. If this were to occur, further community level spread is considered unlikely as this virus has not acquired the ability to transmit easily among humans.

Avian influenza A(H9N2) viruses
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Current situation:
One new laboratory-confirmed human case of A(H9N2) virus infection was reported to WHO from China in a 7-month-old girl from Guangdong province. The case developed mild illness on [11 Dec 2016], was not hospitalized and has recovered. She had exposure to a live poultry market prior to the illness onset. No abnormalities were observed among close contacts of the case at the time of reporting. Avian influenza A(H9N2) viruses are enzootic in poultry in China.

Risk Assessment:
1. What is the likelihood that additional human cases of infection with avian influenza A(H9N2) viruses will occur? Most human cases are exposed to the A(H9N2) virus through contact with infected poultry or contaminated environments. Human infection tends to result in mild clinical illness. Since the virus continues to be detected in poultry populations, further human cases can be expected.

2. What is the likelihood of human-to-human transmission of avian influenza A(H9N2) viruses?
No case clusters have been reported. Current epidemiological and virological evidence suggests that this virus has not acquired the ability of sustained transmission among humans, thus the likelihood is low.

3. What is the risk of international spread of avian influenza A(H9N2) virus by travellers?
Should infected individuals from affected areas travel internationally, their infection may be detected in another country during travel or after arrival. If this were to occur, further community level spread is considered unlikely as this virus has not acquired the ability to transmit easily among humans.

Overall Risk Management Recommendations
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– WHO does not advise special traveller screening at points of entry or restrictions with regard to the current situation of influenza viruses at the human-animal interface. For recommendations on safe trade in animals from countries affected by these influenza viruses, refer to OIE guidance.

– WHO advises that travellers to countries with known outbreaks of animal influenza should avoid farms, contact with animals in live animal markets, entering areas where animals may be slaughtered, or contact with any surfaces that appear to be contaminated with animal faeces. Travellers should also wash their hands often with soap and water. Travellers should follow good food safety and good food hygiene practices.

– Due to the constantly evolving nature of influenza viruses, WHO continues to stress the importance of global surveillance to detect virological, epidemiological and clinical changes associated with circulating influenza viruses that may affect human (or animal) health. Continued vigilance is needed within affected and neighbouring areas to detect infections in animals and humans. As the extent of virus circulation in animals is not clear, epidemiological and virological surveillance and the follow-up of suspected human cases should remain high.

– All human infections caused by a new influenza subtype are notifiable under the International Health Regulations (IHR, 2005). State Parties to the IHR (2005) are required to immediately notify WHO of any laboratory-confirmed case of a recent human infection caused by an influenza A virus with the potential to cause a pandemic. Evidence of illness is not required for this report.

– It is critical that influenza viruses from animals and people are fully characterized in appropriate animal or human health influenza reference laboratories and reported according to international standards. Under WHO’s Pandemic Influenza Preparedness (PIP) Framework, Member States are expected to share their influenza viruses with pandemic potential on a regular and timely basis with the Global Influenza Surveillance and Response System (GISRS), a WHO-coordinated network of public health laboratories. The viruses are used by the public health laboratories to assess the risk of pandemic influenza and to develop candidate vaccine viruses.


Communicated by:
ProMED-mail
<promed@promedmail.org>

The report also includes useful links to additional information:
WHO human-animal interface web page
Cumulative number of confirmed human cases of avian influenza A(H5N1) reported to WHO
Avian influenza A(H7N9) information
WHO avian influenza food safety issues
World Organisation of Animal Health (OIE) web page: web portal on avian influenza
Food and Agriculture Organization of the UN (FAO) webpage: Avian Influenza
OFFLU [joint OIE-FAO global network of expertise on animal influenzas]

The evolutionary trends of the non-human influenza viruses must be closely and regularly monitored for emergence of potential pandemic strains. In view of the Influenza A/H5 associated poultry outbreaks being reported from over 40 countries in Asia, Africa and Europe, enhanced surveillance at the human animal interface is the key to early detection and response to pandemic threats. – Mod.UBA]

See Also

Avian influenza, human (12): China (HE,HN) H7N9, WHO on alert 20170125.4787381
Avian influenza, human (11): Uganda, H5 susp, NOT 20170124.4787380
Avian influenza, human (10): Indonesia (LA) RFI 20170123.4785841
Avian influenza, human (09): Uganda, H5 susp, RFI 20170122.4779120
Avian influenza, human (08): China (HN) H7N9, fatal 20170122.4779060
Avian influenza, human (07): China, Macau, H7N9 20170118.4773390
Avian influenza, human (06): China (HE, HU) H7N9 20170116.4767537
Avian influenza, human (05): China, H7N9 20170113.4763810
Avian influenza, human (04): China H7N9 20170110.4750850
Avian influenza, human (03): China, H7N9 20170108.4745726
Avian influenza, human (02): China (Hong Kong) H7N9, WHO update 20170105.4740477
Avian influenza, human (01): China (JX), H7N9 20170102.4736553

2016
—-
Avian influenza, human (52): WHO, human-animal interface 20160625.4308644
Avian influenza, human (45): WHO, human-animal interface 20160523.4239090
Avian influenza, human (44): China, H7N9, WHO 20160518.4228384
Avian influenza, human (43): China, H5N6, mutations, WHO 20160507.4205906
Avian influenza, human (41): China (HN) H5N6 20160428.4186019
Avian influenza, human (40): China (HU) H5N6 20160423.4178977
Avian influenza, human (34): China, H5N6, H7N9, WHO 20160325.4118113
Avian influenza, human (12): China (GD) H5N6 20160118.3946852
Avian influenza, human (11): China (SC) H5N1 20160114.3936791
Avian influenza, human (07): China (GD) H5N6 20160111.3927489
Avian influenza, human (05): China (GD) H5N6 20160108.3921314
Avian influenza, human (04): China (GD) H5N6 20160106.3915832
Avian influenza, human (03): Egypt (BA) H5N1 20160106.3915791
Avian influenza, human (02): China (GD) H5N6 20160105.3911192

2015
—-
Avian influenza, human (133): WHO assessment human-animal interface 20151220.3881202
Avian influenza, human (118): CDC H5 virus risk assessment 20150731.3548675
Avian influenza, human (115): human-animal interface, SA status comments 20150718.3520025
Avian influenza, human (107): WHO assessment 20150521.3376485
and other items in the archives
………………………………………….uba/ao/ml

Source:
A ProMED-mail post
ProMED-mail is a program of the International Society for Infectious Diseases


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