Wednesday, December 07, 2016

WHO Update On 2 Recent H5N6 Cases In China



















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Twice in just over two weeks (see here and here), we've seen reports of new human cases of H5N6 in China, bringing the total reported in 2016 to 9 (see map above). 

So far, the number of human infections with H5N6 remains low, and we've reassuringly seen no signs of efficient human-to-human transmission.

However, with the virus now arrived in South Korea and Japan, and an analysis of its growing diversity in China (see Cell Host Microbe: Genesis, Evolution and Prevalence of HPAI H5N6 In China) raising concerns over its potential threats to public health, all eyes are on this virus.


Today the World Health Organization has published an update on those two recent cases.


Disease outbreak news
7 December 2016 


The National Health and Family Planning Commission (NHFPC) of China has notified WHO of two laboratory-confirmed cases of human infection with avian influenza A(H5N6) virus.
Details of the cases
  • On 21 November 2016, a human case of infection with avian influenza A(H5N6) virus was reported in a 47-year-old female living in Wugang Prefecture, Hunan Province who developed symptoms on 18 November 2016. She was admitted to hospital on the same day in critical condition. On 20 November 2016, the case was confirmed as infected with avian influenza A(H5N6) virus by laboratory testing, supplemented with clinical and epidemiological findings. The epidemiological investigation is ongoing.
  • On 1 December 2016, an additional human case of infection with avian influenza A(H5N6) virus was reported in a 30-year-old female living in Guangxi Province who developed the disease on 8 November 2016. She was admitted to hospital on 18 November 2016, and at the time of notification, was in critical condition. She had a history of exposure to dead poultry prior to illness onset. 127 close contacts are being monitored, and at the time of notification, none of the close contacts have experienced symptoms. The epidemiological investigation is ongoing.
Public health response


The Chinese Government has taken the following surveillance and control measures:
  • Collecting sample from the cases and conducting laboratory tests.
  • Intensified treatment of the cases; conducting epidemiological investigation of the cases; tracking and managing close contacts, and medical observation of close contacts.
  • Strengthening sentinel surveillance of pneumonia of unknown causes and regular influenza; strengthening etiological surveillance of influenza/avian influenza viruses.
WHO risk assessment


WHO, through its Global Influenza Surveillance and Response System (GISRS), continues to closely monitor the avian influenza A(H5N6) virus and other zoonotic influenza events. So far, the overall public health risk associated with the avian influenza A(H5N6) virus has not changed. Avian influenza A(H5N6) viruses have caused severe infection in humans, and thus far, human infections with the virus seem to be sporadic with no ongoing human-to-human transmission. However the specific risk associated with the virus strains infecting the reported cases will be assessed when the viruses are received and characterized in the GISRS laboratories.

The risk of international disease spread is considered to be low at this point in time. WHO continues to assess the epidemiological situation and conduct further risk assessment based on the latest information.

WHO advice

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

WHO does not advise special screening at points of entry with regard to this event, nor does it currently recommend any travel or trade restrictions. As always, a diagnosis of infection with an avian influenza virus should be considered in individuals who develop severe acute respiratory symptoms while travelling in or soon after returning from an area where avian influenza is a concern.

WHO encourages countries to continue strengthening influenza surveillance, including surveillance for severe acute respiratory infections (SARI) and influenza-like illness (ILI) and to carefully review any unusual patterns, ensure reporting of human infections under the IHR (2005), and continue national health preparedness actions.
    

Saudi MOH Announces 1 Primary MERS Case In Riyadh
















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For the sixth day running, KSA is reporting a new MERS case, today involving a 56 y.o male from Riyadh, listed in stable condition, and whose risk exposure is unknown.

Today's case is the 17th MERS case reported in the past 11 days, and the 12th primary case without a known risk exposure. Four others had recent camel exposure, while a 5th was a household contact of a known case. 

The MOH also announces 2 deaths among previously announced cases, leaving 16 people under treatment in the Kingdom.




Japan : Wild Bird H5N6 Update












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Excluding poultry, Japan - as of 1800 hrs (local time) today - has now recorded 41 HPAI positive wild birds across 9 Prefectures. Not all of these reports have been validated as being due to H5N6, but all that have been fully tested have turned out to be this recently arrived subtype. 
Japan's Ministry of Environment handles the non-farm detections of the virus (wild birds & environment), and their Information about the highly pathogenic avian influenza web page has been updated almost daily since H5N6 arrived in Japan in mid-November.
Since we last checked in on Friday (see Japan: H5N6 Spreading Rapidly Via Migratory Birds), the MOE has posted 13 new reports (see below).

So many, that it is getting difficult to keep track (Note: Not all of the above reports have been confirmed). 

Luckily, today the MOE also posted a summary chart, showing when and where 41 wild birds have tested positive for the HPAI.

http://www.env.go.jp/nature/dobutsu/bird_flu/

As in Europe, where reports of H5N8 are coming in almost hourly, any listing is already outdated before it can be published. 

Exactly why H5N6 and H5N8 appear to be spreading faster, farther, and with more virulence than we've seen before is - as yet - a mystery, although a study (see EID Journal: HPAI A(H5Nx) Viruses With Altered H5 Receptor-Binding Specificity) recently suggested:
`Altered receptor-binding properties might affect the balance between HA and NA, enable the virus to acquire different NA subtypes, and might result in altered host range and spreading.'

Regardless of the cause, neither virus appears to be slowing down. Regions and countries that have not yet been visited need to be alert to the possibility they could be next.

Tuesday, December 06, 2016

DEFRA: UK Declares A Pre-Emptive Prevention Zone Against H5N8

H5N8 Spread as of Dec 4th- Credit ESA




















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Although the UK has yet to report H5N8 in wild birds or poultry, the virus has been detected just across the English Channel in France, and so today the UK's Chief Veterinary Officer has ordered a 30-day `Prevention Zone' to try to prevent infection.

The Government Chief Vet has declared a Prevention Zone introducing enhanced biosecurity requirements for poultry and captive birds, helping protect them from a strain of avian flu circulating in mainland Europe. The zone covers England and will remain in place for 30 days.

Keepers of poultry and other captive birds are now required to keep their birds indoors, or take appropriate steps to keep them separate from wild birds.

Outbreaks of Highly Pathogenic Avian Influenza (H5N8) have been confirmed in poultry and wild birds in several countries across Europe. No cases of H5N8 have been found in the UK and this order is a precautionary measure to help prevent potential infection from wild birds.

Public Health England (PHE) advises that the threat to human health remains very low.

Defra is continuing to monitor the situation closely and has increased its surveillance activity, while keepers are being urged to reinforce biosecurity measures on their premises.
Chief Veterinary Officer Nigel Gibbens said:

While no cases of H5N8 avian flu have been found in the UK, and PHE advises the public health threat is low, we are closely monitoring the situation across Europe and have scaled up surveillance in response to the heightened risk.
As a precaution, and to allow time for poultry and captive bird keepers to put in place appropriate biosecurity measures, we have declared a 30-day Prevention Zone to reduce the risk of infection from wild birds.
Even when birds are housed a risk of infection remains so this must be coupled with good biosecurity—for example disinfecting clothing and equipment, reducing poultry movement and minimising contact between poultry and wild birds.
Poultry keepers are advised to be vigilant for any signs of disease in their birds and any wild birds, and seek prompt advice from their vet if they have any concerns. They can help prevent avian flu by maintaining good biosecurity on their premises, including:
  • cleansing and disinfecting clothing, footwear, equipment and vehicles before and after contact with poultry – if practical, use disposable protective clothing;
  • reducing the movement of people, vehicles or equipment to and from areas where poultry are kept to minimise contamination from manure, slurry and other products and using effective vermin control;
  • thoroughly cleaning and disinfecting housing at the end of a production cycle;
  • keeping fresh disinfectant at the right concentration at all points where people should use it, such as farm entrances and before entering poultry housing or enclosures; and
  • minimising direct and indirect contact between poultry and wild birds, including making sure all feed and water is not accessible to wild birds.

Nature: Risk Assessment of Recent Egyptian H5N1 Influenza Viruses










 


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Over the summer of 2014, HPAI H5N1 picked up several key mutations in Egypt (see Eurosurveillance: Emergence Of A Novel Cluster of H5N1 Clade 2.2.1.2) which are believed to have helped increase its transmissibility from poultry to humans.
Six months later we witnessed the largest human outbreak of H5N1  on record (see EID Dispatch: Increased Number Of Human H5N1 Infection – Egypt, 2014-15), with roughly 160 cases reported over five months.

Last January, in EID Journal: H5N1 In Egypt, we looked at a study that suggested there may have been tens (perhaps, hundreds) of thousands of (mostly mild) human H5N1 infections in Egypt over the past decade.
The authors based their assumption on a limited serological study that found antibodies for H5 in roughly 2% of the people tested.  

Regardless, two facts are clear.  The winter of 2014-15 produced  biggest outbreak of human H5N1 infection ever recorded, and the number of new variants of H5N1 circulating in Egypt has increased markedly over the past couple of years.

For reasons that are far less clear, the number of human infections reported by Egyptian officials over the winter of 2015-16 dropped precipitously.

Yesterday Nature's Scientific Reports published the first detailed analysis of nine recently isolated varieties of H5N1 circulating in Egyptian poultry, and found three of them displayed (limited) transmission via respiratory droplets in ferrets.

While they had difficulty reproducing these results, they suspect that the transmissibility of H5N1 has increased slightly, thereby raising the threat from the virus.

The abstract, and a couple of excerpts follow, but hit the link to read the study in its entirety.

Risk assessment of recent Egyptian H5N1 influenza viruses

    A.-S. Arafa, S. Yamada[…]Y. Kawaoka

Abstract

Highly pathogenic avian influenza (HPAI) viruses of the H5N1 subtype are enzootic in poultry populations in different parts of the world, and have caused numerous human infections in recent years, particularly in Egypt. However, no sustained human-to-human transmission of these viruses has yet been reported.
We tested nine naturally occurring Egyptian H5N1 viruses (isolated in 2014–2015) in ferrets and found that three of them transmitted via respiratory droplets, causing a fatal infection in one of the exposed animals. All isolates were sensitive to neuraminidase inhibitors. However, these viruses were not transmitted via respiratory droplets in three additional transmission experiments in ferrets.
Currently, we do not know if the efficiency of transmission is very low or if subtle differences in experimental parameters contributed to these inconsistent results. Nonetheless, our findings heighten concern regarding the pandemic potential of recent Egyptian H5N1 influenza viruses.

(SNIP)

The HPAI H5N1 viruses were introduced into Egyptian poultry populations in 2006 as descendants of the Qinghai Lake lineage of H5N1 viruses, which belong to subclade 2.2 of the WHO classification system of HPAI H5N1 influenza viruses. Since then, extensive evolution of these viruses has produced several subclades (Supplementary Fig. S1)2,3,4,5,6,7,8. Almost all recent human cases in Egypt have been caused by viruses of subclades 2.2.1 and 2.2.1.2.
In early 2015, a novel cluster within clade 2.2.1.2 was reported that contains all recent human isolates and may have replaced previously circulating clade 2.2.1.2 viruses9. Given that HPAI H5N1 viruses in Egypt evolve rapidly and have caused a substantial number of human infections, we here characterized the respiratory droplet transmissibility of nine Egyptian HPAI H5N1 influenza viruses in ferrets.

Discussion

None of the several highly pathogenic H5N1 viruses found in nature have previously been shown to transmit via respiratory droplets in ferrets or guinea pigs (reviewed in ref. 29). Previously, our groups speculated that Egyptian HPAI H5N1 viruses may have increased pandemic potential because they encode amino acids in HA that enable binding to human-type receptors, encode the PB2-E627K mutation that allows efficient replication in mammals, and lack a glycosylation site at positions 153–155 of HA30,31. This finding, together with the alarming increase in human HPAI H5N1 virus infections in Egypt in 2014–2015, prompted us to test the respiratory droplet transmissibility of recent Egyptian HPAI H5N1 viruses in ferrets.
While our first study demonstrated respiratory droplet transmission among ferrets for three of nine HPAI H5N1 viruses, this finding was not reproducible in three additional transmission experiments. The transmission efficiency of these viruses in ferrets may be very low, such that subtle differences in experimental conditions (such as the air flow, and health of the animals, and/or animal handling) may have affected the outcomes of these studies.
Collectively, these data suggest that contemporary Egyptian HPAI H5N1 viruses may possess the ability to transmit among mammals, although not at the level of seasonal human influenza viruses.
       (Continue . . . )


A new, potential complication comes with the likely introduction of HPAI H5N8 into Egypt's poultry population.  How that will ultimately affect the continued transmission, or evolution, of H5N1 (or H5N8) is unknown.

But the plot definitely thickens . . . .

 

FAO: Serbia Reports H5N8 In 6 Dead Swans

http://empres-i.fao.org/empres-i/2/obd?idOutbreak=219980&rss=t
Credit FAO












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The number of European countries not reporting H5N8 continues to dwindle as Serbia reports the detection of the virus in 6 dead swans discovered in the northern part of their country.




Almost a month ago, very near the start of the European spread of H5N8, neighboring Croatia: MOA Confirmed H5N8 In WIld Swans.