Hong Kong: Wild Bird Found Infected With H5N6

Photo Credit- Wikipedia

 

# 9945

 

While we rarely hear of avian flu infected wild birds out of China (likely due to less than robust surveillance & reporting) – over the past decade we’ve seen numerous reports out of Hong Kong (see Egrets, They’ve Had A Few . . .  and Hong Kong: Two H5 Positive Gulls Found) of sick or dead migratory birds with the H5N1 virus.

 

In December of 2008 Hong Kong saw their first outbreak of H5N1 in domesticated poultry in nearly 6 years. In early 2009 it was announced that the H5N1 outbreak was `likely’ caused by infected migratory birds.  See Wild Birds Eyed As Likely Source Of Hong Kong Bird Flu  Outbreak.

 

Up until the past couple of years, the H5N1 virus has been the primary concern, but with the recent expansion of H5 and H7 viruses in Chinese poultry and the recent arrivals of H5N8 in Taiwan and Japan, H5N1 is now far from the only threat.

Last week is was reported that a Peregrine falcon tested positive for H5 virus in Hong Kong, and that further tests were underway to determine the subtype.  Today we learn that this bird was infected - not with H5N1 – but with the recently emerged H5N6 virus.

 

First case of H5N6 virus found in wild bird in Hong Kong

A spokesman for the Agriculture, Fisheries and Conservation Department (AFCD) said today (April 16) that the carcass of a peregrine falcon found at a construction site on Hung Yuen Road, Hung Shui Kiu, Yuen Long on April 9 was confirmed to be H5N6-positive after a series of laboratory tests.

It is the first case of H5N6 virus found in a wild bird in the territory. The AFCD will closely monitor the situation.

The AFCD will continue to conduct inspections of poultry farms to ensure that proper precautions against avian influenza have been implemented.

The spokesman reminded people to observe good personal hygiene. "They should avoid personal contact with wild birds or live poultry and clean their hands thoroughly after coming into contact with them," he said.

Ends/Thursday, April 16, 2015
Issued at HKT 18:01

 

 

H5N6 is one of several HPAI H5 reassortants that have appeared in China over the past couple of years (others include H5N8, H5N2, H5N3, H5N5), and like its more famous H5N1 cousin – H5N6 has demonstrated the ability to infect humans.

 

Although we only first heard about H5N6 a year ago (see (see Sichuan China: 1st Known Human Infection With H5N6 Avian Flu), it has since been reported across large swaths of China and as far south as central Vietnam. Last October, in China: H5 AI Rising, we looked at 24 recently reported outbreaks of H5N6 across China.

 

The following month, in FAO-EMPRES Report On The Emergence And Threat Of H5N6, we looked at an analysis of H5N6, and other recently emerged avian flu viruses in China. Since then, two more human cases have been reported see China Reports 3rd H5N6 Case (Fatal) – Yunnan Province), of which only one survived.

 

Although it has not spread as well or as far as the recently emerged H5N8 virus (and its reassortant progenies),  H5N6 is nonetheless a virus to watch.

USGS: Alaska - A Hotspot For Eurasian Avian Flu Introductions

 

# 9891

 

Although the arrival of HPAI H5 viruses of Eurasian origin to North America this winter was met with surprise, it wasn’t a completely unexpected event.  For years we’ve watched as the USGS and  the U.S. Fish and Wildlife Service in Alaska have worked to test and track bird migrations and the avian influenza viruses they carry.

 

In 2008, in USGS: Genetic Evidence Of The Movement Of Avian Influenza Viruses From Asia To North America, we saw evidence that suggested migratory birds play a larger role in intercontinental spread of avian influenza viruses than previously thought.

A couple of years later, in Where The Wild Duck Goes, we looked at a USGS program that used Satellite Tracking To Reveal How Wild Birds May Spread Avian Flu.  While it was H5N8 that finally made the jump to north America, at the time, the HPAI fear was from the H5N1 virus . From the report:

 

“Because northern pintails in Alaska exchange influenza viruses with Asian birds, movement of the H5N1 virus into eastern Russia would increase the risk for its transmission to North America via wild birds -- such as the northern pintail -- that migrate between continents,” said Hupp.

 

Although Atlantic crossing migratory birds are considered potential vectors of avian flu (see The North Atlantic Flyway Revisited), the relatively short distance between Alaska and Siberia – a preferred summer nesting spot for many migratory species – makes the Pacific flyway particularly vulnerable.

Yesterday a new study was published in the Journal Virology which provides even more evidence of this intercontinental avian influenza exchange program.

 

Dispersal of H9N2 influenza A viruses between East Asia and North America by wild birds

Andrew M. Ramey^{a, ,} , Andrew B. Reeves^a, Sarah A. Sonsthagen^a, Joshua L. TeSlaa^b, Sean Nashold^b, Tyrone Donnelly^a, Bruce Casler^c, Jeffrey S. Hall^b

Highlights

• 2924 wild bird samples from western Alaska were screened for influenza A viruses.

• Among 90 viral isolates recovered were two viruses of the H9N2 subtype.

• H9N2 subtype isolates were nearly identical with viruses from China and South Korea.

• Results provide evidence for intercontinental viral dispersal by migratory birds.

---

Abstract

Samples were collected from wild birds in western Alaska to assess dispersal of influenza A viruses between East Asia and North America. Two isolates shared nearly identical nucleotide identity at eight genomic segments with H9N2 viruses isolated from China and South Korea providing evidence for intercontinental dispersal by migratory birds.

 

Additional background information is provided by the following USGS press release.

 

New Technology Helps Identify Dispersal of Avian Flu Virus between Asia and Alaska

Released: 3/31/2015 1:00:00 PM

ANCHORAGE, Alaska — In a new study published today, scientists from the U.S. Geological Survey and U.S. Fish and Wildlife Service harnessed a new type of DNA technology to investigate avian influenza viruses in Alaska.  Using a “next generation” sequencing approach, which identifies gene sequences of interest more rapidly and more completely than by traditional techniques, scientists identified low pathogenic avian influenza viruses in Alaska that are nearly identical to viruses found in China and South Korea.

The viruses were found in an area of western Alaska that is known to be a hot spot for both American and Eurasian forms of avian influenza.

“Our past research in western Alaska has shown that 70 percent of avian influenza viruses isolated in this area were found to contain genetic material from Eurasia, providing evidence for high levels of intercontinental viral exchange,” said Andy Ramey, a scientist with the USGS Alaska Science Center and lead author of the study.  “This is because Asian and North American migratory flyways overlap in western Alaska.”

The new study, led by the USGS, found low pathogenic H9N2 viruses in an Emperor Goose and a Northern Pintail.  Both of the H9N2 viruses were nearly identical genetically to viruses found in wild bird samples from Lake Dongting, China and Cheon-su Bay, South Korea.

“These H9N2 viruses are low pathogenic and not known to infect humans, but similar viruses have been implicated in disease outbreaks in domestic poultry in Asia,” said Ramey.

There is no commercial poultry production in western Alaska and highly similar H9N2 virus strains have not been reported in poultry in East Asia or North America, so it is unlikely that agricultural imports influenced this result.

The finding provides evidence for intercontinental movement of intact avian influenza viruses by migratory birds. The USGS recently released a publication about the detection of a novel highly pathogenic H5N8 virus in the U.S. that is highly similar to the Eurasian H5N8 viruses. This suggests that the novel re-assortment may be adapted to certain waterfowl species, enabling it to survive long migrations. That virus, and associated strains, have now spread from early detections in wild and domestic birds in Pacific states to poultry outbreaks in Minnesota, Missouri and Arkansas.

“The frequency of inter-hemispheric dispersal events of avian influenza viruses by migratory birds may be higher than previously recognized,” said Ramey.

While some of the samples for the project came from bird fecal samples collected from beaches at Izembek National Wildlife Refuge, most of the samples came from sport hunters.

“For the past several years, we’ve worked closely with sport hunters in the fall to obtain swab samples from birds and that has really informed our understanding of wildlife disease in this area,” said Bruce Casler, formerly a biologist with the USFWS Izembek National Wildlife Refuge and a co-author of the study. None of the viruses found in harvested birds from Izembek Refuge are known to infect humans, but hunters should always follow safe meat handling and cooking guidelines when processing wild game.

The paper, “Dispersal of H9N2 influenza A viruses between East Asia and North America by wild birds” was published today in the journal Virology. A summary of all samples collected at the Izembek Refuge will be described in a subsequent publication.

Additional information about avian influenza can be found at the following web sites:

• USGS Alaska Science Center
• USGS National Wildlife Health Center

 

 

For years the rallying cry that `Sick birds don’t fly’ has been used to argue that migratory birds aren’t to blame for the spread of the virus, even though it has been shown that some species of birds (particularly ducks) can carry – and presumably spread – the virus asymptomatically.

 

A recent statement by the UN CMS/FAO Co-Convened Scientific Task Force on Avian Influenza and Wild Birds maintains that typically the spread of HPAI virus is via contaminated poultry, poultry products and inanimate objects although wild birds may also play a role.

 

We explored the often bitter debate between the poultry industry and conservationists over the role of migratory birds in spreading avian flu in Bird Flu Spread: The Flyway Or The Highway?, and while poultry industry practices often factor heavily, it is hard to refute the notion that wild birds are at least partially responsible.

 

For more on the role of migratory birds, you may wish to revisit:

 

Erasmus Study On Role Of Migratory Birds In Spread Of Avian Flu

PNAS: H5N1 Propagation Via Migratory Birds

EID Journal: A Proposed Strategy For Wild Bird Avian Influenza Surveillance

PLoS One: North Atlantic Flyways Provide Opportunities For Spread Of Avian Influenza Viruses

CIDRAP: Role Of Migratory Birds Questioned In US H5N2 Outbreaks

Major Global Migratory Flyways – Credit FAO

 

# 9843

 

Four months ago, in Bird Flu Spread: The Flyway Or The Highway?, we looked at the often contentious debate over the role that migratory birds play in the global spread of avian influenza viruses.  A week later, in H5N8: A Case Of Deja Flu?, we compared the recent spread of HPAI H5N8 to the 2005-2006 geographic expansion of H5N1.

 

While poultry producers are often quick to blame wild or migratory birds, not everyone concurs, with a recent statement by the UN CMS/FAO Co-Convened Scientific Task Force on Avian Influenza and Wild Birds stating that typically the spread of HPAI virus is via contaminated poultry, poultry products and inanimate objects although wild birds may also play a role.

 

The way that HPAI H5N8 virus spread out of  East Asia to Europe, Japan, Taiwan, and North America in less than 12 months certainly suggests that migratory birds played a role in its dissemination, although direct proof is lacking. We’ve seen that some birds can carry avian influenza viruses without ill effect, and when they encounter other birds, can `share’ their viral cargo along their migratory flyway. 

 

And where flyways overlap, there is a greater chance of spreading a virus from one region to another. And as you can see by the map above, they overlap a lot.

 

The USDA’s APHIS (Animal Plant Health Inspection Service) assessment on the arrival of HPAI H5 viruses to the Pacific Northwest this winter unambiguously focused on migratory birds.  In Update on Avian Influenza Findings in the Pacific Flyway dated Feb 4, 2015, they state:

 

The H5N8 virus originated in Asia and spread rapidly along wild bird migratory pathways during 2014, including the Pacific flyway.  In the Pacific flyway, the H5N8 virus has mixed with North American avian influenza viruses, creating new mixed-origin viruses.  This is not unexpected.  These mixed-origin viruses contain the Asian-origin H5 part of the virus, which is highly pathogenic to poultry.  The N parts of these viruses came from North American low pathogenic avian influenza viruses.

 

But the abrupt shift of the H5N2 virus from the Pacific Northwest to the heartland of America – a 1000 mile leap to the east in the dead of winter – has some questioning whether migratory birds are behind every outbreak.  Once introduced into a region’s poultry, we’ve seen avian flu viruses spread to other farms through lapses in biosecurity and the movement of poultry products, transport, or personnel.  

 

With 900 poultry farms in Taiwan battling a multi-subtype outbreak of HPAI H5 this winter – even if the virus was initially introduced to the island by migratory birds – it stretches credulity that infected wild birds paid personal visits to each and every of them.

 

CIDRAP News’s Robert Roos has much more on all of this, with a perspective article published last night.  Follow the link to read:

 

 

Role of wild birds in US H5N2 outbreaks questioned

Robert Roos | News Editor | CIDRAP News

Mar 18, 2015

LHG Creative Photography / Flickr cc Pintail duck.

The notion that wild birds played a key role in bringing highly pathogenic avian influenza (HPAI) viruses from Asia to western North America and more recently to the Midwest has been implicit in government statements about recent outbreaks. But some wildlife disease experts are warning against jumping to easy conclusions.

The story goes back to last November and December, when an HPAI H5N2 virus struck several poultry farms in southern British Columbia. Those outbreaks triggered increased surveillance for avian flu in the United States, and a matching virus showed up in December in a wild northern pintail duck in northwestern Washington state. At the same time, a Eurasian strain of H5N8 virus was found in a captive gyrfalcon in the same area.

(Continue . . . )

 

For more on this debate, you may wish to revisit:

 

Erasmus Study On Role Of Migratory Birds In Spread Of Avian Flu

PNAS: H5N1 Propagation Via Migratory Birds

EID Journal: A Proposed Strategy For Wild Bird Avian Influenza Surveillance

PLoS One: North Atlantic Flyways Provide Opportunities For Spread Of Avian Influenza Viruses

 

Erasmus Study On Role Of Migratory Birds In Spread Of Avian Flu

Major Global Migratory Flyways – Credit FAO

 

# 9678

 

Ever since the avian H5N1 virus began its big move in 2005-2006 - where it abruptly spread out of a handful of southeast Asian countries to more than 50 new countries in Europe, the Middle East and Western Africa - there has been a long (and often bitter) debate over the role of wild and/ migratory birds in the spread of avian flu.

 

Governments and poultry producers have often been quick to blame migratory birds when outbreaks occur, while conservationists have pointed fingers directly at the poultry producers, citing crowded factory farms, poor biosecurity, and poultry transportation and smuggling as the prime factors.

 

Not having a bird in this fight, it seems perfectly reasonable to me that both play major roles in the spread of avian flu.  But there seems little in the way of common ground for these opposing groups.

 

When the H5N8 virus erupted in South Korean poultry and wild birds in January of last year, the government announced that Migratory Birds Likely Source Of H5N8 Outbreak.  Just 24 hours later, in H5N8 Spreads, Debate Over Source Intensifies, we saw the UN’s Scientific Task Force on Avian Influenza and Wild Birds quickly respond with a statement saying:

 

“There is currently no evidence that wild birds are the source of this virus and they should be considered victims not vectors ” and that “. . . focusing attention on wild birds can misdirect critical resources away from effective disease control and result in negative conservation outcomes and loss of biodiversity.”

 

When H5N8 turned up in unexpectedly in Europe last fall, the same task force issued another statement in December, softening their position every so slightly, by granting:

 

Typically, spread of HPAI virus is via contaminated poultry, poultry products and inanimate objects although wild birds may also play a role.

 

They included the following recommendations:

• a. conduct thorough epidemiological evaluation to determine the true source of the virus including possible transmission through national and international poultry trade, and mechanisms of transmission among domestic and wild birds;
• b. regardless of the source of infection, focus disease control actions on affected farms, with the aim of minimising the risk of disease spread to other poultry farms and/or wildlife, ensuring that affected and nearby farms are biosecure to prevent wildlifepoultry contact;
•  c. ensure there is no consideration of killing of wild birds or negatively affecting wetland habitats as potential disease control measures; and
• d. recognise that focussing attention on wild birds, to the exclusion of other potential viral vectors, can misdirect critical resources away from effective disease control and result in continued spread among poultry populations and economic losses to farmers and national income, as well as negative conservation outcomes and loss of biodiversity.

The then went on to present their rationale for why avian viruses are unlikely to have traveled rapidly via birds from east to west when migratory routes are predominantly north-south corridors.

In all fairness, I would point out that these migratory routes overlap, which would seem to afford ample opportunities for lateral movement of viruses.

 

But at the same time we are seeing nearly 700 poultry farms in Taiwan battling a multi-subtype outbreak of HPAI H5 - and while likely introduced to the island by migratory birds – it stretches credulity that infected wild birds paid personal visits to each of them.

 

Once introduced into a region’s poultry, outbreaks often appear to be exacerbated by lapses in biosecurity and the movement of poultry products, transport, or personnel.  Something we looked at last November in Bird Flu Spread: The Flyway Or The Highway?

 

Entering this fray today are researchers from Erasmus University, including Ron Fouchier, who have an article in Science Magazine, that is alas, mostly behind a pay wall.  We do have some additional details available via the BBC, however.  First the link:

 

How a virus travels the world

Josanne H. Verhagen, Sander Herfst,  Ron A. M. Fouchier

In November and December 2014, highly pathogenic avian influenza (HPAI) viruses of the H5 subtype originating from China were detected in poultry and wild birds in various countries of Asia and Europe, and, for the first time, in North America. These incursions of newly emerging HPAI H5 viruses constitute a threat to animal and potentially human health and raise questions about the routes of transmission.

 

From the BBC:

 

'Wild birds may spread flu virus'

By Helen Briggs Environment Correspondent

Migratory birds may be spreading viruses that cause bird flu around the world, say scientists.

<SNIP>

"More poultry outbreaks could occur in the future, especially in countries that are ill-prepared," a team led by Dr Ron Fouchier wrote in the journal, Science.

"Despite the currently low public health risk, the outbreaks should be monitored closely, given that several animal species are susceptible and that influenza viruses are generally unpredictable."

Wild birds with long migratory routes should be monitored for exposure to H5N8 and control measures in poultry should be updated, as they appear to be "insufficient", they added.

Scientists are also investigating other ways that bird flu viruses can spread around the world, including through illegal poultry trade and contamination of vehicles or equipment.

(Continue . . . )

 

The BBC story goes on to point out that the science isn’t settled, and the European Food Safety Authority recently stated the route of spread of the disease remained uncertain.

 

On the other hand, our own USDA APHIS (Animal Plant Health Inspection Service) is far less ambiguous when discussing the recent arrival of HPAI H5 viruses to the Pacific Northwest.  In Update on Avian Influenza Findings in the Pacific Flyway last Modified: Feb 4, 2015, they state:

 

The H5N8 virus originated in Asia and spread rapidly along wild bird migratory pathways during 2014, including the Pacific flyway.  In the Pacific flyway, the H5N8 virus has mixed with North American avian influenza viruses, creating new mixed-origin viruses.  This is not unexpected.  These mixed-origin viruses contain the Asian-origin H5 part of the virus, which is highly pathogenic to poultry.  The N parts of these viruses came from North American low pathogenic avian influenza viruses.

Somehow, despite the preponderance of evidence, I suspect this debate is nowhere near being settled.

PNAS: H5N1 Propagation Via Migratory Birds

Source - OIE 63 Countries Report H5N1 Avian Influenza in Domestic Poultry/Wildlife 2003-2010).

# 9480

 

Although migratory birds have been labeled a `convenient scapegoat’ by conservationists who instead point their finger at the poultry industry for the spread of avian flu (see this recent statement by the UN CMS/FAO Scientific Task Force on Avian Influenza and Wild Birds), a fair review of the data makes the wild bird connection difficult to ignore.

 

Not that migratory birds are the only factor, since evidence strongly suggests poultry operations (including legal and illegal trade & transportation) have contributed mightily to the evolution and spread of avian viruses as well.

 

This is an ongoing, and often bitter debate I covered at some length  last month in Bird Flu Spread: The Flyway Or The Highway?, and previously here, here, and here.

 

Yesterday, in EID Journal: A Proposed Strategy For Wild Bird Avian Influenza Surveillance, we looked at recommendations for a more consolidated and cost effective program to monitor avian flu viruses in birds, while previously (see The North Atlantic Flyway Revisited & Satellite Images Show Where The Wild Goose Goes) we’ve looked at some of the individual migratory bird studies.

 

With the recently emerged HPAI H5N8 avian virus showing up not only in Europe, but in North America this fall, and an upstart H5N6 making inroads in across China and Vietnam, defining the role of migratory birds in the spread of these viruses gains even more importance.

 

Today we’ve a report from PNAS that looks back over much of the data gathered since the emergence of H5N1 in Southeast Asia, and presents the case that migratory birds have play a significant role in its propagation.  Among other things, they cite that along migratory flyways, H5N1 outbreaks closely match the seasonal arrival of migratory flocks.

 

They are quick to clarify, however, that migratory birds are likely just one of several underlying transmission networks, and that in some cases where the virus was detected in wild birds, the virus may have transmitted from poultry to birds instead of the other way around. 

As with all studies, the authors list a number of limitations, and so you’ll probably want to read this report in its entirety.  I’ve only excepted a couple of highlights, so follow the link to read:

 

 

Avian influenza H5N1 viral and bird migration networks in Asia

Huaiyu Tian^a,¹, Sen Zhou^b,¹, Lu Dong^c,¹, Thomas P. Van Boeckel^d,¹, Yujun Cui^e,¹, Yarong Wu^e, Bernard Cazelles^f,^g, Shanqian Huang^a, Ruifu Yang^e, Bryan T. Grenfell^d,^h,², and Bing Xu^a,^b,ⁱ,²

 

Abstract

The spatial spread of the highly pathogenic avian influenza virus H5N1 and its long-term persistence in Asia have resulted in avian influenza panzootics and enormous economic losses in the poultry sector. However, an understanding of the regional long-distance transmission and seasonal patterns of the virus is still lacking. In this study, we present a phylogeographic approach to reconstruct the viral migration network. We show that within each wild fowl migratory flyway, the timing of H5N1 outbreaks and viral migrations are closely associated, but little viral transmission was observed between the flyways. The bird migration network is shown to better reflect the observed viral gene sequence data than other networks and contributes to seasonal H5N1 epidemics in local regions and its large-scale transmission along flyways. These findings have potentially far-reaching consequences, improving our understanding of how bird migration drives the periodic reemergence of H5N1 in Asia.

Significance

Highly pathogenic avian influenza virus H5N1 first emerged in Asia and subsequently unfolded into the first avian influenza panzootic, causing major economic losses in the poultry sector. However, we still do not understand the regional long-distance transmission and seasonal patterns of H5N1. In this study, we addressed this issue by combining H5N1 outbreak records, whole-genome sequences of viral samples, and satellite tracking data for four species of migratory birds in Asia. We show that timing of H5N1 outbreaks and viral migration are closely associated with known bird migration routes. The flyway is the major viral transmission barrier to the intracontinental spread of H5N1 by migratory birds in Asia, whereas geographic distances within the flyways have little effect on H5N1 transmission.

(Continue . . . )

 

For more on the recent emergence and spread of the H5N8 virus, and how it compares to the sudden expansion of H5N1 in the middle of the last decade, you may wish to revisit:

H5N8: A Case Of Deja Flu?

 

EID Journal: A Proposed Strategy For Wild Bird Avian Influenza Surveillance

Major Global Migratory Flyways – Credit FAO

 

# 9476

 

Six weeks ago, in Bird Flu Spread: The Flyway Or The Highway?, we looked at the ongoing  debate over the role that migratory birds play in the global spread of avian influenza viruses.  A week later, in H5N8: A Case Of Deja Flu?, we compared the recent spread of H5N8 to the 2005-2006 geographic expansion of H5N1.

 

While poultry producers are often quick to blame wild or migratory birds, not everyone agrees, with a recent statement by the UN CMS/FAO Co-Convened Scientific Task Force on Avian Influenza and Wild Birds stating that typically the spread of HPAI virus is via contaminated poultry, poultry products and inanimate objects although wild birds may also play a role.

The reason this debate continues (aside from partisan interests on both sides of the debate) is that we lack an ongoing coordinated global surveillance system to show us exactly how these viruses traveled.  While many countries conduct surveillance, it is often sporadic, reactive, and the standards and methods employed vary widely.

 

Yesterday the EID Journal carried a letter from a number of international experts (representing the USDA, OIE, St. Jude Children’s Research Hospital, WHO, EcoHealth Alliance, etc.) calling for a coordinated effort to study these viruses in wild and migratory birds.

 

Online Report

Global Avian Influenza Surveillance in Wild Birds: A Strategy to Capture Viral Diversity

Catherine C. Machalaba, Sarah E. Elwood, Simona Forcella, Kristine M. Smith, Keith Hamilton, Karim B. Jebara, David E. Swayne, Richard J. Webby, Elizabeth Mumford, Jonna A.K. Mazet, Nicolas Gaidet, Peter Daszak, and William B. Karesh

Abstract

Wild birds play a major role in the evolution, maintenance, and spread of avian influenza viruses. However, surveillance for these viruses in wild birds is sporadic, geographically biased, and often limited to the last outbreak virus.

To identify opportunities to optimize wild bird surveillance for understanding viral diversity, we reviewed responses to a World Organisation for Animal Health–administered survey, government reports to this organization, articles on Web of Knowledge, and the Influenza Research Database. At least 119 countries conducted avian influenza virus surveillance in wild birds during 2008–2013, but coordination and standardization was lacking among surveillance efforts, and most focused on limited subsets of influenza viruses.

Given high financial and public health burdens of recent avian influenza outbreaks, we call for sustained, cost-effective investments in locations with high avian influenza diversity in wild birds and efforts to promote standardized sampling, testing, and reporting methods, including full-genome sequencing and sharing of isolates with the scientific community.

(Continue . . . )

 

This letter contains a long, detailed overview of the current state of surveillance, and offers suggestions as to how a cost-effective surveillance network could be created, so you’ll want to read the entire article 

 

They conclude by writing:

 

The cost of avian influenza virus outbreaks in poultry is substantial; outbreaks of influenza A(H5N1) virus during 2004–2009 caused US $30 billion in damage (29), and the frequency of highly pathogenic avian influenza outbreaks in poultry appears to be increasing (11). Rather than sporadically releasing large amounts of funding for wild bird surveillance when specific avian influenza viruses emerge, sustained national, regional, and global investments can provide the targeted baseline level of systematic surveillance we propose. Many countries, especially where avian influenza virus diversity in wild birds is highest, are already investing in some form of avian influenza virus surveillance in wild birds.

Current efforts should be refined by leveling the investment roller coaster that has funded subtype-specific wild bird surveillance toward a lower-cost but long-term investment in collecting and sequencing wild bird avian influenza viruses. Global coordinating bodies, such as OFFLU (a network linking influenza experts and laboratories working with poultry and swine influenzas and World Health Organization expertise) (13), provide collaborative forums for government agencies and researchers to compile and share sequences and isolates. For wild bird avian influenza viruses specifically and all influenza viruses, we would be remiss not to work toward coordinated surveillance to support more effective assessment, preparation, and response for emerging influenza viruses that pose potential public health threats.

The North Atlantic Flyway Revisited

Global Flyways – Credit FAO

 

# 9372

 

It is pretty clear from the way the HPAI H5N1 virus spread out of South East Asia to Europe and the Middle East in the middle of the last decade, that migratory birds can play a major role in its dissemination.  Many species are able to carry avian influenza viruses without ill effect, and when they encounter other birds, can `share’ their viral cargo along their migratory flyway.

 

Where flyways overlap, there is a greater chance of spreading a virus from one region to another. And as you can see by the map above, they overlap a lot.

 

During the peak of H5N1’s great expansion during the middle of the last decade, the number of countries affected by that emerging avian virus jumped from 16 to over 60 in less than 24 months (see OIE 63 Countries Report H5N1 Avian Influenza in Domestic Poultry/Wildlife 2003-2010).

 

And for awhile, there were concerns that the virus would eventually wing its way to North America – with the most likely route viewed as coming from Siberian birds crossing the Bering Straits into Alaska and Canada.  When that didn’t happen, and when the H5N1 threat in Europe retreated, many concluded we were `protected’ from such viral intrusions by both distance and oceans.

 

Last March, when our infectious disease attentions were pretty much evenly divided between MERS in the Middle East and the winding down of the second wave of H7N9 in China, I blogged on a study that appeared in PLoS One that looked at the potential for European Avian flu viruses to hop the Atlantic and end up in North America (see Thursday, March 20, 2014 PLoS One: North Atlantic Flyways Provide Opportunities For Spread Of Avian Influenza Viruses).

 

In view of the recent emergence of a new, highly pathogenic avian influenza virus (H5N8) now turning up in Europe – and the fact this study probably didn’t get the attention it deserved last spring -  it seems appropriate to revisit that study (funded by the USGS and NIAID) that confirms at least the potential of avian flu viruses to cross the Atlantic to reach North America.  

 

First the press release from the USGS, then a link to the study and some excerpts. I’ll have a bit more after.

North Atlantic May Be a New Route for Spread of Avian Flu to North America

Released: 3/19/2014 5:10:00 PM

The North Atlantic region is a newly discovered important pathway for avian influenza to move between Europe and North America, according to a U.S. Geological Survey report published today.

USGS scientists and Icelandic partners found avian flu viruses from North America and Europe in migratory birds in Iceland, demonstrating that the North Atlantic is as significant as the North Pacific in being a melting pot for birds and avian flu. A great number of wild birds from Europe and North America congregate and mix in Iceland's wetlands during migration, where infected birds could transmit avian flu viruses to healthy birds from either location.

By crossing the Atlantic Ocean this way, avian flu viruses from Europe could eventually be transported to the United States. This commingling could also lead to the evolution of new influenza viruses. These findings are critical for proper surveillance and monitoring of flu viruses, including the H5N1 avian influenza that can infect humans.

"None of the avian flu viruses found in our study are considered harmful to humans," said Robert Dusek, USGS scientist and lead author of the study. "However, the results suggest that Iceland is an important location for the study of avian flu and is worthy of special attention and monitoring."

The study also highlighted the new finding that gulls play an important role in moving avian flu viruses across the North Atlantic.

During the spring and autumn of 2010 and autumn of 2011, the USGS researchers and Icelandic partners collected avian influenza viruses from gulls and waterfowl in southwest and west Iceland (see map). By studying the virus’ genomes — an organism’s hereditary information — the researchers found that some viruses came from Eurasia and some originated in North America. They also found viruses with mixed American-Eurasian lineages.

"For the first time, avian influenza viruses from both Eurasia and North America were documented at the same location and time," said Jeffrey Hall, USGS co-author and principal investigator on this study. "Viruses are continually evolving, and this mixing of viral strains sets the stage for new types of avian flu to develop."

(Continue . . . )

Excerpts from PLoS One:

North Atlantic Migratory Bird Flyways Provide Routes for Intercontinental Movement of Avian Influenza Viruses

Robert J. Dusek mail, Gunnar T. Hallgrimsson, Hon S. Ip, Jón E. Jónsson, Srinand Sreevatsan, Sean W. Nashold, Joshua L. TeSlaa, Shinichiro Enomoto, Rebecca A. Halpin, Xudong Lin, Nadia Fedorova, Timothy B. Stockwell, Vivien G. Dugan,  [ ... ], Jeffrey S. Hall

Abstract

Avian influenza virus (AIV) in wild birds has been of increasing interest over the last decade due to the emergence of AIVs that cause significant disease and mortality in both poultry and humans. While research clearly demonstrates that AIVs can move across the Pacific or Atlantic Ocean, there has been no data to support the mechanism of how this occurs. In spring and autumn of 2010 and autumn of 2011 we obtained cloacal swab samples from 1078 waterfowl, gulls, and shorebirds of various species in southwest and west Iceland and tested them for AIV. From these, we isolated and fully sequenced the genomes of 29 AIVs from wild caught gulls (Charadriiformes) and waterfowl (Anseriformes) in Iceland. We detected viruses that were entirely (8 of 8 genomic segments) of American lineage, viruses that were entirely of Eurasian lineage, and viruses with mixed American-Eurasian lineage. Prior to this work only 2 AIVs had been reported from wild birds in Iceland and only the sequence from one segment was available in GenBank. This is the first report of finding AIVs of entirely American lineage and Eurasian lineage, as well as reassortant viruses, together in the same geographic location. Our study demonstrates the importance of the North Atlantic as a corridor for the movement of AIVs between Europe and North America.

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Our data demonstrate that the North Atlantic serves as a route for intercontinental movement of AIV and it will be important to track the further dissemination of these viruses, in whole, or in part, into the Icelandic avian community and, more significantly, into the avian communities of Europe or North America.

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For more on the geographic expansion of bird flu viruses, you may wish to revisit:

 

FAO On The Potential Threat Of HPAI Spread Via Migratory Birds

Bird Flu Spread: The Flyway Or The Highway?

FAO-EMPRES Report On The Emergence And Threat Of H5N6

Germany & Japan Both Report H5N8 In Wild Birds

International Migratory Flyways

 

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On Tuesday, in H5N8: A Case Of Deja Flu?, I recounted the history of great H5N1 bird flu expansion of 2005-2007, where that virus jumped from only 9 Southeast Asia countries to 60+ nations across Europe and Asia.  While it is far from clear whether H5N8 will follow H5N1’s flight path, we continue to see evidence of its encroachment to other regions of the world.

Since Tuesday, the Netherlands has reported several additional farms infected (see Netherlands: 2nd Farm At Kamperveen Showing Signs Of Bird Flu), and both Japan and Germany have found evidence of the virus in wild or migratory birds.

First stop, a report today from Reuters of a 2nd detection of H5N8 in Germany, this time in wild birds.

Germany reports second case of bird flu - H5N8 found in wild bird

BERLIN Sat Nov 22, 2014 10:51am EST

Nov 22 (Reuters) - German authorities on Saturday confirmed a second case of the H5N8 strain of bird flu in the eastern state of Mecklenburg-Vorpommern, with the virus found in a wild bird.

The strain is highly contagious among birds but has never been detected in humans.

"For the first time, the H5N8 virus has been confirmed in a wild bird in Mecklenburg-Vorpommern," Agriculture Minister Christian Schmidt said in a statement.

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Japan, which saw a brief incursion of the H5N8 virus last April while South Korea was battling against multiple outbreaks (see Japan’s Avian Flu Outbreak Identified As H5N8 ), and which reported a little more than a week ago H5N8 In Migratory Bird Droppings, has now reported to the OIE another detection of H5N8 in Chiba prefecture.

 

According to a Japan News article earlier today (Bird flu detected in Chiba Prefecture), with this second detection, Japan will now raise its nationwide bird flu alert from 2 to 3, and dispatch an emergency wild bird survey team.

While none of this is absolute confirmation that the H5N8 virus arrived in Western Europe on the wings of migratory birds, when you combine these recent detections in birds, and the statement from the OIE: European H5N8 Strain `Closely Related’ To Korean Strain, the preponderance of evidence swings in that direction.

 

For more on this you may wish to revisit these recent related blogs:

FAO On The Potential Threat Of HPAI Spread Via Migratory Birds

Bird Flu Spread: The Flyway Or The Highway?

EID Journal: Subclinical HPAI In Vaccinated Poultry – China

H5N8: A Case Of Deja Flu?

Three recent Outbreaks Of H5N8

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For those of us who have been covering avian influenza for a decade or more, the detection of avian H5N8 – a newly emergent influenza virus previously only seen in Korea and far eastern China –  in three recent outbreaks in Europe is somewhat reminiscent of the great bird flu diaspora of 2005-2006.

 

Up until the middle of 2005, the H5N1 virus – which first appeared in China in 1996, and sparked an outbreak in Hong Kong in 1997 – was essentially a southeast Asian problem.   

 

The virus was quashed – temporarily – due to a massive culling in Hong Kong in 1997, but returned in February of 2003, infecting two family members (and likely a third, who died untested) with recent travel history to Fujian Province, China.  Another case was retrospectively identified in Beijing (originally diagnosed as SARS) in November of 2003.

 

In December 2003, the Republic of Korea reported outbreaks in Poultry, and at a zoo in Thailand two tigers and two leopards – fed raw poultry – died of H5N1.  Our first clue that felines were susceptible to the virus.

In January of 2004, Vietnam reported poultry and human infections. In rapid succession Japan, Cambodia, Laos, and Hong Kong report poultry and wild bird infections. Thailand reports two human infections as well. Before the end of the year, Indonesian and Malaysia would see the virus arrive as well.

 

In 2005, after the huge die off of migratory birds at Qinghai Lake, the virus would suddenly take flight – carried by migratory birds – to Russia, the Ukraine, Turkey, and even Kuwait.

 

By the end 2005, 17 countries had reported infections.

 

The big geographic expansion came in 2006, when the virus jumped to an additional 39 countries in a single year.  Suddenly there were reports in Italy, Bulgaria, Nigeria, Iraq, Iran, Germany, France, The United Kingdom, Egypt . . . . 

In most of these regions outbreaks were sporadic, and quickly contained (often at great cost).  But in Egypt, the virus  became endemic, and remains so to this day, exacting a heavy toll on the poultry industry and causing a small number of human illnesses and deaths every year.

Another half dozen countries were added to the list in 2007, but by 2008, the virus seemed in retreat outside of the bird-flu endemic countries of Indonesia, China, Vietnam, India, Pakistan, Korea, and Egypt.  

 

For the past few years the role of migratory birds in avian flu’s geographic spread appeared to decline.

 

While the H5N1 threat remains, over the past couple of years, a stealthy (and highly pathogenic to humans) H7N9 has captured out attentions.  As it doesn’t sicken birds, it can spread unnoticed, and is often only discovered after humans in contact with infected birds fall ill.  

 

Unlike H5N1, the role of migratory birds in the spread of H7N9 is less than clear.

 

Last January, the HPAI H5N8 virus appeared on a duck farm in South Korea – and in wild and migratory birds - and over the next couple of months managed to spread to more than 3 dozen farms. 

50 day Spread of H5N8 - Map Credit Japan’s MAFF

 

While highly pathogenic to birds, it hasn’t (yet) shown the ability to infect humans. South Korea did report Dogs With H5N8 Antibodies last spring. As the virus spreads, however, it continues to evolve (see EID Journal: Describing 3 Distinct H5N8 Reassortants In Korea), giving rise to concerns that it could someday pose a greater human health threat.

 

For now, H5N8 is viewed as primarily a threat to poultry.

 

Now, across Europe there are concerns that we could see a repeat of the 2006 influx of bird flu.  Not only could this cause serious economic losses for the poultry industry, it would allow a novel influenza virus to mingle with – and possibly reassort with – other flu viruses with uncertain results.

 

While the focus right now is on H5N8, there are several other recently emerged avian flu strains of concern in Asia, any of which could eventually show up in Europe.    H7N9 – which has caused the deaths of more than 100 people in China and is exceedingly hard to detect in poultry – is a serious concern.

Others include H5N6 – which killed at least one person in China last spring, H10N8 which infected three people last winter in China, and H5N3 – which was only first reported in China last month.

 

Today, the World Health Organization is warning that it is likely we will see additional outbreaks of avian flu in European poultry – and while the public health risk is low – the risks are not zero.

 

Bird flu spread likely, human cases unlikely but possible: WHO

By Tom Miles

GENEVA Tue Nov 18, 2014 9:16am EST

(Reuters) - New cases of bird flu detected in Europe will likely hit other bird populations and may infect a few people, though the virus is highly unlikely to spread in the human population, the World Health Organization (WHO) said on Tuesday.

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In March of 2013, in EID Journal: Predicting Hotspots for Influenza Virus Reassortment, we looked at a study that selected East-Central China a one of the top hotspots in the world for the creation of zoonotic influenza viruses. And on Thursday of last week, in EID Journal: Subclinical HPAI In Vaccinated Poultry – China, we looked at the diminishing benefits from China’s poultry vaccination schemes.

 

Finally, last Sunday, in FAO On The Potential Threat Of HPAI Spread Via Migratory Birds, we looked at concerns over how easily those viruses could spread via interconnected migratory flyways.  While we don’t know with certainty how H5N8 has spread to Europe, migratory birds are high on the list of suspects.

While it is possible we could see a repeat of the 2006-2007 expansion of H5N1 with the H5N8 virus, this time around we’ve got much better biosecurity in poultry operations in Europe than we did eight years ago, and considerable experience dealing with outbreaks.

But if the past couple of years has taught us anything, it is that the number of new avian flu subtypes continues to rise, and that the challenges of keeping them at bay are only going to increase with time.

FAO On The Potential Threat Of HPAI Spread Via Migratory Birds

 

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Although it may sound so very 2006, once again we appear to be faced with a westward expansion of one or more novel avian flu strains out of Asia.  Readers with good memories will recall the scramble in middle of the last decade to prevent the spread, and entrenchment, of H5N1 into Europe (see 2007’s Germany Reports More Infected Poultry & UK: Bird Flu Cull Complete).

 

Between a strict culling policy, and enhanced biosecurity measures, Europe managed to keep H5N1 from becoming endemic in poultry, despite repeated introductions of the virus.

 

China, which has relied predominantly on a vaccination policy, has managed to protect their poultry flocks from excess mortality and morbidity, but – as we discussed last week (see EID Journal: Subclinical HPAI In Vaccinated Poultry – China – now finds itself with multiple clades and subtypes of HPAI in circulation and a roster of poultry vaccines that are slowly losing their effectiveness.

 

While HPAI has proven to be primarily a threat to poultry operations, we have seen hundreds of human infections with both H5N1 and H7N9 (including many fatalities) over the past decade, and scientists worry that either could – over time – adapt better to human physiology and present a pandemic threat. 

 

While H5N1 has a ten-year head start, H7N9 has caused far larger outbreaks over the past couple of years, and is currently viewed as the bigger public health threat.  Upstart viruses such as H5N6, H5N8, and H10N8 are too new to effectively gauge their threat potential, but bear watching (see China: H5 AI Rising).

 

The arrival of H5N8 in Germany last week, and its detection in wild bird feces in Japan this week, along with today’s  report Netherlands: `Severe’ HPAI Outbreak In Poultry, is a reminder that nature’s laboratory is open, and operating 24/7, and that it continues to serve up new disease threats.

 

The role of migratory birds in spreading HPAI has been a controversial one (see Bird Flu Spread: The Flyway Or The Highway?), with wildlife enthusiasts quick to blame the poultry industry, citing poor biosecurity, overcrowded factory farms, and smuggling.  

 

When infected migratory birds land in Japan, or HPAI shows up thousands of miles away from home, it is difficult to ignore the potential role of birds in AI spread.

 

On Friday the FAO published the following report on the potential movement of avian flu viruses out of Asia, and into Europe, via migratory birds.

 

Avian influenza A(H5N8) detected in Europe… a journey to the West?

Germany has become the first European country to report an outbreak of highly pathogenic avian influenza caused by an A(H5N8) virus genetically similar to one spreading in the Republic of Korea since January. The virus causes high mortality in poultry. The route of introduction into Germany remains unclear, but the long-distance spread from Asia to Europe indicates that wild birds may play a role. FAO is emphasizing the need for continued vigilance worldwide and heightened efforts on farms to prevent contact between poultry and wild birds.

What we know

The Federal Republic of Germany officially reported the outbreak on 6 November 2014 to the World Organisation for Animal Health (OIE) and the European Union. German authorities have since contained the outbreak, which occurred on a turkey farm. The Government is working to clarify the source of infection through ongoing epidemiological investigations while also searching for any additional cases through targeted surveillance in the surrounding areas. Genetic information released immediately by the Friedrich Loeffler Institute, the National Reference Laboratory for avian influenza in Germany, shows that this H5N8 is very similar to viruses detected in China, the Republic of Korea and Japan this year.

Akin to the highly pathogenic avian influenza H5N6 virus that emerged in southern China around the same time (see FAO press release, 22 September 2014 and EMPRES Watch, November 2014) this H5N8 originated from various reassortment events involving, among others, HPAI H5N1 viruses circulating in Southeast Asia.
Outbreak data from the Republic of Korea and Germany shows that H5N8 causes high mortalities in chickens and turkeys. Experimental studies with the Korean virus, on the other hand, suggest no associated severe mortality in domestic or wild ducks. However, ducks can shed high amounts of virus (reference).

A role for wild birds?

Much still needs to be clarified about this virus, including how it found its way to Germany. The fact that the virus is genetically close to a virus from the Republic of Korea and that wild ducks may be affected without dying could suggest a role for wild birds in the spread of the virus over long distances and further onward transmission to poultry.

Wild birds were linked previously to the spread of H5N1 HPAI virus from Asia to Europe and Africa from 2005 onwards. With regard to H5N8, experts hypothesize that the virus may have travelled during the spring season from eastern Asia into the breeding grounds of migratory birds in Central Asia. These migratory birds may now be carrying the virus with them as they migrate into more moderate climates.

What this means

The detection of H5N8 in Europe is a reminder that avian influenza viruses still represent a global threat to animal health and the international poultry industry. FAO is calling for worldwide vigilance and targeted surveillance as well as optimized biosecurity measures on farms. Avian influenza spreads most easily from infected farms to uninfected farms through common processes involved in the poultry industry and where biosecurity is low. Reducing direct and indirect contact between poultry and wild birds is an important part of good biosecurity, especially in light of various virus strains that may be carried by wild birds.

Experimental infections with H5N8 demonstrate the Republic of Korea show that certain aquatic wild bird species, like mallards, may not exhibit overt signs of disease or mortality. Likewise, the virus may not cause high mortality in domestic ducks. Therefore, active surveillance is important for early detection both in aquatic wild birds and in poultry.

What FAO suggests

• Any significant increase in mortality, neurological signs or reductions in food intake or egg production in ducks and chickens should be immediately reported and investigated.
• Any unexplained excess mortality in wild birds, especially aquatic species, should be fully reported and investigated.
• Poultry should be kept indoors with good standard biosecurity measures implemented on farms aiming at minimizing contact with wild birds as well as between poultry farms.
• Hunters should properly dispose of any remains from hunted wild birds. Hunters should also avoid contact with domestic poultry during or directly after hunting.

Japan: H5N8 In Migratory Bird Droppings

Credit U.S. Fish and Wildlife Service

 

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The emergence last January of a new Highly Pathogenic H5N8 avian influenza virus in South Korea resulted in the destruction of more than 13 million birds in dozens of farms throughout the Korean peninsula. 

 

Japan saw a brief incursion  last April (see Japan’s Avian Flu Outbreak Identified As H5N8), but forewarned by the Korean outbreak, as able to quickly contain that outbreak.

Since then sporadic outbreaks continue to pop up in South Korea, and H5N8 was recently reported in Northwestern China, and last week in Northern Germany (see UK: Defra Preliminary Assessment On Germany’s H5N8 Outbreak In Poultry).

Given its detection in wild ducks in Korea, and its widespread and rapid geographic dispersal, migratory birds are eyed as playing a role in the spread of the virus (see Bird Flu Spread: The Flyway Or The Highway?). 

 

With migratory birds heading south for their winter nesting grounds, Japan once again finds itself on guard against another introduction of the virus.  Today, Japan’s Ministry of Environment has announced the detection of the H5N8 virus in migratory bird dropping collected in Yasugi, Shimane Prefecture.

Avian influenza virus, detected from the migratory bird droppings Shimane Yasugi

November 14, 2014

 

Ministry of the Environment on October 13, Shimane Prefecture Yasugi highly pathogenic from droppings of amber butterfly found in the avian influenza virus (H5N8 subtype) has announced has been detected, and.

Virus in the droppings of study of migratory birds that Kyotosangyodai is doing on its own, was found from 2 specimens were collected in three days. Ministry of the Environment is to specify the surrounding 10 km close to wild bird monitoring emphasis area, began to dispatch preparation of emergency investigation team.

 

Japan, Korea, and Hong Kong are all part of the great East Asian - Australasian Flyway. All three are the winter and fall home for a variety of migrating birds - many of which spend their summers in Siberia, China, and Mongolia – areas where avian influenza viruses have been detected in wild bird populations before (see Siberian Birds Test Positive For H5N1 Antibodies and Siberian Birds Show H5N1 Antibodies).

 

In 2010, Japan was faced with multiple introductions of H5N1 (see Japan: Hooded Crane Positive For H5N1) from migratory birds overwintering in the national reserve in Izumi City, Kagoshima Prefecture. In 2011, even more infected birds arrived (see Japan’s Bird Flu Dilemma).

 

While there is not a lot that officials can do about migratory birds flying in with highly pathogenic viruses, they can warn local poultry operations to beef up biosecurity and surveillance, and can gear up to respond to any outbreaks.

 

With the recent emergence of H5N6, H5N8, H5N3, H10N8  - along with the already established H5N1, H5N2 and H7N9 viruses -  more than ever, much of Asia and Europe must now stay alert for the possibility of seeing the arrival of one of these viruses.

For more on the potential of migratory birds to spread avian viruses, you may wish to revisit:

PLoS One: North Atlantic Flyways Provide Opportunities For Spread Of Avian Influenza Viruses

EID Journal: H5N1 Branching Out

FAO: On The Trail Of Avian Influenza