Reply to Dr. Niman's argument that wild birds are spreading avian influenza

I thought this issue was important enough to repost here from www.agonist.org.  The points in italics are comments from Dr. Niman.

Quote from: niman on Today at 08:26:14pm
You have already provided the evidence.  The geese at Qinghai Lake were H5N1 positive and there is no reported outbreaks in domestic birds there.  Moreover, the OIE report cited 4 additional species.  Thus, the OIE report has 5 species of waterfowl that are H5N1 positive.

Highly pathogenic avian influenza has never been shown to be sustained in wild bird populations. The birds at Qinghai either could have gotten it from an area where H5N1 was widespread up until at least last fall (i.e., throughout western China) or from India where H5N1 has not been isolated, conspiracy theories aside.

Quote from: niman on Today at 08:26:14pm
H5N1 is in India, but reported as ABBT.  Serologocal tests are not designed to give false positive.  You just make it up as you go along.
.

ABBT?  Never heard of it.  Is this part of the conspiracy theory?

Epidemiology 101: serological tests are screening tests.  You want them to pick up anything that might be positive (i.e., very sensitive tests).  However, increasing sensitivity reduces specificity - the likelihood of false positives (i.e., false positives become more likely).  This is not a bad thing, as screening tests are then backed up with confirmatory tests - in this case PCR virus isolation and bioassays in chickens.

There have been no such back up tests in India as far as I'm aware.  Further, there have been no reports of H5N1 in Indian poultry.  The virus has simply not been found there.

In contrast, we know H5N1 was widespread in China until last fall.

I can either believe the Chinese outbreak was not contained, or India is really playing into your conspiracy theory and suppressing all information that H5N1 is there.

Quote from: niman on Today at 08:26:14pm
Clearly you are not looking for evidence, which is in abundance at GenBank with has new sets of H5N1 sequences each season.

Yes.  New sequences of H5N1 are found each season in domestic birds.  But not in wild birds.  Low pathogenic strains are found in wild birds, and I hypothesize that its the conditions in domestic poultry/waterfowl production systems that favour evolution of high pathogenicity.

Dr. Niman, I respect that you have had a long and succesful career in microbiology, but I don't see any publications in epidemiology or wildlife ecology (your papers are listed here).  I think you have done the world a good service by keeping the pressure up on avian influenza, but I think you have to recognize that there is more to this than simply recombination.  We need a holistic approach to preventing the pandemic that is based on an understanding of the ecological and epidemiological context.

We need to focus on how we can promote wildlife, human, and domestic animal health, and the way to do that is to figure out effective strategies.  I am arguing that focussing on culling wild birds as was suggested by the news article that started this thread, is ineffective.

We need to promote biosecurity on poultry/domestic waterfowl farms:
- prevent contact between wild and domestic birds
- understand the conditions on farms that favour evolution of high pathogenicity
- understand movement of captive birds, both in poultry/waterfowl production as well as the illegal wild bird trade, so that we find the most effective control points to stop transmission.
- promote safe practices on farms so that people are not exposed.

I think we all have the same goal - to prevent the pandemic.  

Philippino bird flu strategy

Here is a story on the Philippines' strategy to prevent the introduction of avian influenza.

The good: they are enacting a monitoring strategy for wild birds, something many other countries are not doing.

The bad: it seems to suggest they plan on "stamping out" migratory birds in local areas if avian influenza is found.

The ugly: killing migratory birds is not an effective strategy, and may have important conservation consequences as the article itself suggests.

As I argued earlier, cases of highly pathogenic avian influenza in wild birds are likely spillover from outbreaks in domestic poultry.

No CWD in Maryland or Missouri...yet

According to a press report by the Maryland DNR there are no signs of CWD among 872 free-ranging deer in the state. The sampling regime was intensive:

"The state’s current sampling effort was designed such that if 1 percent of the deer in either population had CWD, there is a 98 percent chance the disease would be detected."

That maybe a high prevalence for a recently introduced disease (let Damien fight me this one) but it is still a reasonable starting point.Maryland has been monitoring CWD since 2002 and has passed legislation prohibiting the transportation of deer across state lines (the most likely cause of the appearance of CWD in NY and probably WI). Good going!

Spending tons more money, Missouri has also been cleared of the disease this year (10,352 sample from 52 counties!!). Somebody should teach them something about sampling!!

ahumadameister.

One case of avian flu confirmed in Indonesia

This report has just confirmed a positive human case for avian flu in Indonesia. Although only one out of 81 human blood samples was found positive back in May, the case has been confirmed just recently:

"The infected man is a farm labourer who was exposed to sick chickens when a wave of avian flu swept over the southern Sulawesi island earlier this year." 

The man is asymptomatic, but was believed to be in contact with domestic poultry.

More cases of avian flu in Vietnam

According to this report six new more human cases of avian flu have been reported in the last week in Vietnam.

Human trial of H5N1 vaccine could be dangerous?

According to this report Vietnam is getting ready to test a new vaccine for H5N1 avian flu this summer. However, some are concerned about the methods used to develop this vaccine:

The seed virus used for Vietnam's vaccine was mixed with cancer cells to boost replication, and then grown in monkey kidney cells, a method the article describes as highly unorthodox. It is not the same seed virus as the one approved by the World Health Organization (WHO) for H5N1 vaccine development.

"People could get cancer from the vaccine," according to a TIME quote attributed to Klaus Stohr, head of the WHO's global influenza program.

ahumadameister.

H5N1 samples from Qinghai match those from 2004 outbreak in China

Quote from here:
"Samples recently recovered from China's western Qinghai Province show the virus there has been matched genetically to that found on the southeast coast, researchers say, reigniting a debate over whether it is being spread by migratory birds or human activities."

This information is consistent with my earlier hypothesis (explained here). I'm in the "human activity" is to blame camp.  It seems clear that H5N1 has been in Chinese domestic poultry and/or waterfowl since last June, undetected or unreported.

CWD in PA

Looks like people are thinking along the right ways in Pennsilvania to get ready for CWD. Baning feeding deer during the winter is not very popular among suburbans but will probably minimize contact between individuals, lowering transmission.

ahumadamesiter.

When conservation and disease management clash-Bighorns

This is not news in the world of disease management and conservation. Sometimes the best way to control a disease in wildlife is to cull potentially infectious individuals before they come into contact with susceptible individuals in the population (e.g. CWD). However, when we are talking about endangered species, what should we do?

Found this piece reporting clashes between disease managers and conservation groups regarding what to do with endangered Bighorns that have come into contact with domestic sheep in California. People are worried that bighorns might become sick of pneumonia and other diseases. Of course culling an endangered species is a big problem but I don't think its unethical:

"The proposal to kill wild bighorns to `protect' them from domestic sheep is unwise and unethical," said a letter Monday from the Center for Biological Diversity and Friends of the Inyo. "What is necessary is to get domestic sheep away from bighorns now."

Sure, but once they got into contact what else is to do? What is more unethical: to kill a few animals or let a zoonotic event wipe out the entire species? 

On the other hand, the population size of these bighorns is not extremely high:

"In recent years, the population has climbed to an estimated 350 animals, but officials say that has increased the potential for contact with domestic sheep that carry pneumonia and other diseases that can wipe out bighorn herds."

Sure, but for an epidemic to spread population size has to be above a certain threshold. This is basic epidemiology..

N = (b+a+g)/B

where b is the natural death rate of bighorn sheep, a is the number of babies produced per unit time, g is the recovery rate from the disease and B is contact rate between individuals. B might still be very small if a few bighorns contact a lot of sheep, but once these individuals come into contact with other susceptible bighorns the disease can only spread if 

R0 > BN/(b+a+g)

In other words, the small population size of bighorns might buffer them against a possible zoonotic event. With very simple models we can make "educated guesses" as to what action to take. Go get estimates of b,a,g and B and you might have a better answer! Of course we could always vaccinate more sheep (this is how canine distemper is being controlled in East Africa).

Food for thought....

ahumadameister.

Fungus can help control malaria

Malaria is one of the big human killers, but few people are aware also that malaria can have large impacts on bird and mammal populations, specially when they have been isolated in islands and unexposed to disease for millions of years (such as avian malaria and pox in Hawaii).

Traditionally mosquitoes that bear disease like malaria and pox have been controlled without much success with insecticides. But according to a report in Nature News researchers at Imperial College and Wageningen University, have discovered an effective way of controlling mosquitoes with a fungus (Bauveria bassiana) sprayed in an oil mixture. This affects their mortality, lifespan and results in an 80-fold reduction in their ability to transmit the disease.

There are still issues regarding how long the oil-fungus concotion can last under field conditions, but still encouraging!

ahumadameister

Background on H5N1 in China - are wild birds to blame?

With rampant speculation that wild birds are spreading H5N1 throughout China I thought it important to summarize some of the available information on H5N1 avian influenza in China.

My working hypothesis is that the H5N1 avian influenza outbreak in domestic poultry in Tacheng is a continuation of the 2004 avian influenza epizootic in Chinese domestic poultry. The virus was widespread across China in 2004 with much opportunity for it to circulate without detection after its supposed eradication. Certainlythis happened after the 1997 outbreak in China (see below).

I stand by my previous hypothesis that the outbreak in waterfowl at Qinghai represents a case of spillover from domestic poultry to migratory waterfowl. It remains to be seen whether the spillover occured locally in China or to birds in Southeast Asia which consequently brought it to China.

Although temporally coincident, there is no evidence that the Qinghai waterfowl outbreak and the Tacheng poultry outbreak are related. Certainly the Chinese government promoted the connection in the OIEpost, but I have yet to see evidence.

During outbreaks of highly pathogenic avian influenza, the virus is rarely isolated from wild birds even on affected poultry farms (Swayne and Suarez, 2000; Li et al 2004). In fact, mass die-offs in wild birds associated with avian influenza have only been reported a handful of times (common terns in South Africa in 1961, Becker, 1966; waterfowl and other birds in 2002, Ellis et al. 2004; and the current outbreak in Qinghai, China). Highly-pathogenic strains (HPAI) likely do not circulate in wild populations although wild birds may become infected during outbreaks in domestic poultry (Nestorowicz et al.1987, Melville and Shortridge, 2004).

Surveillance for avian influenza in wild birds is critical to resolving the question of their role in transmission. We need to compare genetic sequences from the viruses isolated at Qinghai to the virus circulating in Southeast Asia as well as the new outbreak inTacheng.

The only effective strategy to prevent transmission of avian influenza from poultry to wild birds (spillover) or from wild birds to poultry (spillback) is improved biosecurity for poultry producers. Contact between wild and domestic birds must be prevented and/or reduced.

Culling of wildlife to control disease is not an effective management strategy. Dr. Wobeser provides some discussion on this topic.

A some background on H5N1 in China:

- H5N1 was first found in Hong Kong and China in domestic waterfowl in 1997. Hong Kong culled all poultry, and the virus was not isolated again in Hong Kong until 2001 (Chen et al. 2004). Although the
outbreak was thought to have ended, the virus circulated in China, from 1999 until 2004 (Cauthen et al 2000, Li et al 2004)

- During these earlier outbreaks, no mortality was seen in wild birds. In 2002, waterfowl and other birds were found to die of H5N1 during an outbreak in captive and semi-captive birds in two zoological parks
in Hong Kong. The outbreak was contained (Ellis et al. 2002).

- By February of 2004, H5N1 was detected in domestic poultry across much of the country (see map), and in pigs. Pigs can be infected with H5N1 without showing clinical signs.

- The H5N1 outbreak continued in 2004, with reports as late as June, however there were no further reports.

References

Becker, W.B. 1966. The isolation and classification of Tern virus:
influenza A-Tern South Africa - 1961. Journal of Hygiene 64:309-320.

Cauthen, A.N., D.E. Swayne, S. Schultz-Cherry, M.L. Perdue, D.L.
Suarez. 2000. Continued circulation in China of highly pathogenic
avian influenza viruses encoding the hemagglutinin gene associated
with the 1997 outbreak in poultry and humans. Journal of Virology 74:
6592-6599.

Chen, H., G. Deng, Z. Li, G. Tian, Y. Li, P. Jiao, L. Zhang, Z. Liu,
R.G. Webster, and K. Yu. 2004. The evolution of H5N1 influenza viruses
in ducks in Southern China. Proceedings of the National Academy of
Sciences 101:10452-10457.

Ellis, T.M. R.B. Bousfield, L.A. Bissett, K.C. Dyrting, G.S.M. Luk,
S.T. Tsim, K. Sturm-Ramirez, R.G. Webster, Y. Guan, and J.S.M. Peiris.
Investigation of outbreaks of highly pathogenic H5N1 avian influenza
in waterfowl and wild birds in Hong Kong in late 2002. Avian Pathology
33:492-505

Li, K.S., Guan, Y., Smith, G.J.D., Xu, K.M., Duan, L., Rahardjo, A.P.,
Puthavathana, P., Buranathal, C., Nguyen, T.D., Estoepangestie,
A.T.S., Chaisingh, A., Auewarakul, P., Long, H.T., Hanh, N.T.H.,
Webby, R.J., Poon, L.L.M., Chen, H., Shortridge, K.F., Yuen, K.Y.,
Webster, R.G., and J.S.M. Peiris. 2004. Genesis of a highly pathogenic
and potentially pandemic H5N1 influenza virus in eastern Asia. Nature
430: 209-213.

Melville, D.S., and K.F. Shortridge. 2004. Influenza: time to come to
grips with the avian dimension. The Lancet Infectious Diseases
4:261-262.

Nestorowicz, A., Y. Kawaoka, W.J. Bean, and R.G. Webster. 1987.
Molecular analysis of the hemagglutin genes of Australian H7N7
influenza viruses: role of passerine birds in maintenance or
transmission. Virology. 160: 411-418.

Swayne, D.E and Suarez, D.L. 2000. Highly pathogenic avian influenza.
Revue of Science and Technology of the Office International des
Epizooties 19:463-482.

Damien
--

Guest Blogger

From June 10 to July 5, there will be a guest blogger, ahumadameister, on wildlifedisease.blogspot.com while I am travelling. He comes to the world of wildlife disease from a theoretical perspective, and is an expert using statistical and simulation techniques to describe ecological patterns of disease in natural populations.

I am really looking forward to coming back from my trip, and reading his insight on disease issues.

Thanks ahumadameister!

Damien

New OIE report on H5N1 in China

HIGHLY PATHOGENIC AVIAN INFLUENZA IN THE PEOPLE'S REPUBLIC OF CHINA

The location of the outbreak is in the far west of China near the border with Kazakhstan, possibly ~2000 km away from the Qinghai migratory bird outbreak.

The report indicates ~1,042 cases in "geese", with 460 deaths and ~13,000 culled. At this point there is no indication of which species, or if these were domestic or free-ranging geese. I would guess they were domestic geese.

The source of infection is still under investigation, but the "mode of spread" is indicated to be "migratory birds". The index farm is abackyard farm.

I'll pass more information along as it becomes available.

Damien

Mysterious Disease Kills 400 Sheep in Mongolia

Mysterious Disease Kills 400 Sheep in Mongolia: "Mysterious Disease Kills 400 Sheep in Mongolia"

It seems that every time there is an outbreak of any kind anywhere near China these days, it must have been H5N1.

I admit to being a little frustrated with this. I find it unsettling that animals that people depend upon, including livestock and wildlife, often suffer from disease issues around the world with no attention from the public health community. Over 60% of diseases that affect humans come from animals as well as over 70% of emerging infectious diseases (reference). This is an alarm that those of us in the wildlife health community have been raising for years, but has fallen on deaf ears. When the gaze of the internet community finally recognizes that human and animal health are inextricably intertwined, it takes a narrow view of the problem and fails to recognize its complexity.

Avian influenza may very well have killed these sheep, but I am very skeptical. There are many other pathogens of greater likelihood that have been killing animals in this region for a very long time.

When it is shown that something else killed these sheep other than H5N1, will the internet community be willing to help the nomadic herdspeople who have, in a very short period of time, lost the equivalent of their life savings, their means of paying for health care or education for their children?

Comment on possiblity of Mumbai die-off being caused by WNV

From ProMED:

------------------------------

Date: Tue, 7 Jun 2005 21:33:22 -0400 (EDT)
From: ProMED-mail
Subject: PRO/AH> Crow die-off - India (Mumbai, Khar-Bandra) (02)

CROW DIE-OFF - INDIA (MUMBAI, KHAR-BANDRA) (02)
***********************************************
A ProMED-mail post

ProMED-mail is a program of the
International Society for Infectious Diseases


Date: Mon 6 Jun 2005
From: Robert G. McLean, PhD


West Nile virus (WNV) infection is one of the possibilities, but the stiff legs and wings were not indicative of WNV-infected American crows -- flaccid paralysis was more common.

WNV strains in the eastern hemisphere are not known to be virulent for birds except for the Israel Goose strain, which could be introduced elsewhere besides North America.

The easiest way to screen for WNV in crows is to use the simple dip-stick test (VecTest) on oral and cloacal swabs from live and recently dead crows. See webpage at:
.

PCR confirmatory tests would be beneficial.

- --
Robert G. McLean, Ph.D.
Program Manager Wildlife Diseases
National Wildlife Research Center
WS/APHIS/USDA
4101 Laporte Avenue
Fort Collins, CO 80521-2154


[West Nile virus infection is only one of many possible explanations for the
death of large numbers of crows in Mumbai and surroundings. Dr. McLean has pointed out that West Nile virus strains in the eastern hemisphere are not known to be virulent for [wild] birds. This true throughout the range of West Nile virus in Western Europe. The American experience is the exception.

Use of the rapid user-friendly diagnostic test described by Dr. McLean would
resolve the question without delay, and allow attention to be focused on
potentially greater hazards such as environmental pollution. - Mod.CP]

***Disclaimer: ProMED-mail has no financial interest in the proprietary
diagnostic test mentioned.***


[Nor do I ... d.]

China orders bloggers to register with government

Please take a moment to learn about this issue.

Update on Mumbai crow die-off

A comprehensive update from Sunjoy Monga.

Why did the chicken cross the road ...

A little levity:

More thoughts on geese photos ...

I asked Dr. Michael Samuel, a professor at the University of Wisconsin who has worked on wildlife disease issues for over twenty years including waterfowl mortalities, to comment on the photos (some of his publications are listed here). Specifically, I wrote:

"
The internet is ablaze with rumours about "thousands" of geese dying
of H5N1 avian influenza in western China. Part of the fire is being
fueled by these pictures, which many claim are of thousands of dead
geese (maybe bar-headed):

http://www.peacehall.com/news/gb/china/2005/06/200506032331.shtml

They point to the fact that there are no geese in the air as further
evidence of a mass mortality.

What do you think? At a goose colony, would you expect loads in the
air? Do these look like dead geese to you? Sorry, I realize the
resolution is poor, but any thoughts you had would be great.

Thanks,

Damien"

His reply was this:

"
Damien -

I agree these pictures are not very good. However, it doesn't look to me like these birds are dead. I see some birds standing in the pictures and many that appear to either be preening or with heads on top of their backs, still others appear to have their heads tucked into their feathers. If many of these birds were dead I would expect them to be laying on the sides or with their heads and necks on the ground. Also I would not expect to see them so regularly spaced as appers in this pictures - looks like a nesting colony to me. I have attached a picture of dead snow geese from Banks Island for your comparison (sorry - I can't get the photo posted - will do so as soon as I can - d.).

I've not yet heard any reports about mass mortality in waterfowl from AI, and this would certainly be typical since we believe that waterfowl are not generally affected by AI.

Mike"

Dr. Samuel followed up with this comment:

"Damien -

Just a couple of followup notes. Your report indicates only a mortality of about 500 birds, it is certainly possible that there could be dead birds scattered in these pictures, but not easily seen given the poor quality.

A second thing to consider is some other disease, one would be avian cholera. Although cholera is not typically reported in Asia it was found in Baikal Teal in the past few years. It would certainly be one of the things I might consider.

Related to the snow goose mortality you should consier that these carcasses were probably a 1-2 months post outbreak. Our best estimates were that aoubt 20,000 - 30,000 birds were killed in this outbreak.

Hope some of this helps.

Mike"

Grounding a Pandemic - New York Times

Grounding a Pandemic - New York Times: "By BARACK OBAMA and RICHARD LUGAR"

A nice editorial summarizing the threats and potential responses associated with pandemic avian influenza.

Re: a topic at www.agonist.com (Bar-headed geese possibly bringing H5N1 from India)

We have to remember that 5 species were officially reported in the Qinghai H5N1 outbreak and likely dozens of waterfowl species congregate at Qinghai. Although Bar-headed geese were found dead, it doesn't mean they brought H5N1 there. Some duck species may carry the virus without showing clinical signs (e.g., this paper in Science - sorry full article only available to subscribers), and this lake is at a crossroad for South and Southeast Asian flyways.

Rather than the virus coming from India, it seems more likely that either a) there is an undetected outbreak H5N1 circulating in local domestic poultry or b) waterfowl were infected from domestic poultry in SE Asia, and consequently brought it to Qinghia.

Update: In response to a fair comment from Dr. Niman (reply #4), I posted this follow up:

Maybe I should clarify my thoughts on this.

Any one of many species of waterfowl that migrate from SE Asia, possibly including duck species that may not show clinical signs, could bring the virus from SE Asia to Qinghai. Once at Qinghai, bar-headed geese could get infected. They didn't have to bring it there to die of it.

I apologize if there was a misunderstanding.

RedNova News - Science - Quantitative Bioscience for the 21st Century

This is a great article (particularly for quantitative geeks like myself):

RedNova News - Science - Quantitative Bioscience for the 21st Century

I'm a little troubled though that the article was clearly copied from a scientific publication (Copyright American Institute of Biological Sciences Jun 2005) but the full citation is not given. I guess it's BioScience?

DPIWE - Disease Affecting Tasmanian Devils - Update

An update from the Tasmanian Department of Primary Industries, Water, and Environment on research on the Tasmanian Devil Facial Tumour Disease is available here:

DPIWE - Disease Affecting Tasmanian Devils - Update: "Latest Information from the Devil Project"

ProMED: Crow die-off in Mumbai

ProMED posted a story on a crow die-off in Mumbai, India today (here is another news story). This issue was first reported by Sunjoy Monga on the birdsofbombay discussion group May 4. So far about 400 dead crows have been reported. Information from Dr. Monga's post-mortem examinations of some crows will be really important.

H5N1 in Qinghai revisited

I was asked to clarify my position with regards to the Qinghai H5N1 outbreak.

In general, I try to view new information as a skeptic. When I question the evidence for a statement or conclusion, it doesn't necessarily mean I don't agree with the conclusion. I just think it is important to not sensationalize or draw premature conclusions on unverified evidence. I would rather dismiss something I agreed with on the grounds that the evidence was insufficient, than use incorrect information to in error support a position I believed in.

I do think that if a highly pathogenic influenza pandemic occurs, it could be the most significant public health crisis since HIV/AIDS. Millions could die, many more could get sick, and the economic fallout could be catastrophic. We need to be prepared, and dilligent in watching for signs that it is occuring. In 1918, without the massive air transportation system we have today, it took only 6-8 months for H1N1 to sweep the globe. Today, one can get from anywhere to anywhere in a frighteningly short amount of time.

That been said, my positions on the Qinghai outbreak are these:

- Although H5N1 has been isolated at Qinghai Nature Preserve, information on the cause of death in the reported dead wild birds is unavailable. Avian influenza commonly circulates in wild birds, and although H5N1 has rarely been isolated from wild birds, it is possible that the virus was incidental to other causes of death. I had a flu earlier this year. If I was hit by a bus, and the pathologist did a swab and was able to isolate the virus, she would not conclude the flu killed me (the bus did). As we hear again and again, a mortality event of this magnitude would be unprecedented if it was caused by H5N1. We should be skeptical of claims that influenza killed these birds without good evidence.

- If it can be shown a significant number of birds did die of H5N1 at Qinghai, then my level of concern would go up. However, this makes the issue a conservation issue, not necessarily a human health issue. Because H5N1 has rarely been isolated from wild birds, the simplest explanation is that the presence of H5N1 is the result of a migratory bird picking up the virus in southeast Asia from an affected domestic poultry farm. Pathogenic avian influenza then could result in increased mortality in wild birds, thus provide an increased threat to species that are already at low density. This illustrates the global trend of livestock diseases affecting wildlife, and causing population declines. We need to recognize that human, livestock and wildlife health are one and the same.

- There is fear that migratory birds could potentially spread H5N1 into new areas. Species that die of H5N1 are unlikely to spread the virus, but of course there is the potential that those species that can carry the virus without getting ill could spread the disease into previously unaffected areas. This brings up the issue of biosecurity. The best way to prevent diseases from going from domestic poultry into wild birds (spillover) and then going back into domestic poultry from wild birds (spillback) is through improved biosecurity. Essentially, contact between domestic poultry and wild birds should be minimized and prevented as much as possible. This protects both domestic and wild birds from a number of diseases, not just avian influenza. Many government agencies will be tempted to cull wild birds in order to “contain” the epizootic – we know this won't work.

- We should be hyper vigilant for human cases of avian influenza. The final impediment stopping the epidemic is human to human transmission. At the first demonstrable sign that avian influenza has acquired the ability to transmit easily among humans, drastic measures should be taken to prevent its global spread. I recognize that there are a few documented cases of human to human transmission already, but so far it seems to be limited.

Governments worldwide are unprepared for the next avian influenza pandemic. As practitioners of wildlife, livestock, and human health, we all have a responsibility to promote policies that will reduce or ameliorate the impact of the next pandemic. However, this cause is not served by being sensational, or by invoking chicken little. We must be cautious in our assessment of “facts” so that when we do raise the alarm, it is credible and receives the attention it deserves among policy makers.

Disinfection photos from Qinghai Province

Disinfection photos

Picture of Bar-headed geese with H5N1 and necropsy photo

Pics here with babelfish translation

C.D.C. Team Investigates an Outbreak of ...

Phew. I feel so much better. We have Ebola in the Congo, Marburg in Angola, H5N1 threatening to sweep the globe, and the CDC sends a team of specialists into West Virginia to tackle .... obesity?

C.D.C. Team Investigates an Outbreak of Obesity - New York Times

Over 8000 Bird Flu Deaths in Gangcha County Qinghai China?

Recombinomics: Over 8000 Bird Flu Deaths in Gangcha County Qinghai China?

Dr. Niman is relying on a machine translation from a Chinese language website where anyone can post. As Crawford Kilian notes, this sounds like Nostradamus.

I think some perspective is necessary. Wild animals die all the time for a variety of reasons. Waterfowl are susceptible to several diseases that cause mass mortalities: thousands of birds die every year in North America from diseases such as avian cholera, duck plague, and avian botulism (a field manual of wild bird diseases is available here). Just skim through this report posted by the United States Geological Survey National Wildlife Health Center where die-offs of many thousands of waterfowl occur regularly.

Apparently more than 100,000 birds congregate on this lake every year. 8000 deaths is likely not only precedented, but possibly normal.

I repeat my earlier cautions. Assuming that these numbers are accurate, we don't know what killed these animals. Just because H5N1 was isolated there doesn't mean it killed every animal that dies.

Update: Dr. Niman is linking to photos apparently showing thousands of dead birds. To me, the nice, uniform spacing between birds, the resting and standing poses suggest that these are nesting birds (although there likely are dead birds in there - birds die all the time). This is what a waterfowl mortality event looks like to me.

thetyee.ca: Blogging the Pandemic

thetyee.ca Blogging the Pandemic: "Avian flu is scary, but a little knowledge is dangerous, too."

This is a great article, discussing the potential for rumours to be amplified on the internet. As I've previously posted, it is important to avoid sensationalizing these stories, despite the apparent utility of rumors in disease surveillance.

Low Pathogenic Avian Influenza found on BC Turkey Farm

From the Canadian Food Inspection Agency:

Canadian Food Inspection Agency - Animal Health - Animal Disease Information: "May 27, 2005
H3 influenza virus found in British Columbia

The Canadian Food Inspection Agency has quarantined a turkey layer farm in Abbotsford, British Columbia based on preliminary results from the British Columbia Ministry of Agriculture, Food and Fisheries (BCMAFF) indicating the presence of the H3 influenza virus in the flock.

The turkey farm is near a swine farm that recently experienced an H3 influenza infection and the virus is suspected to have originated from swine. Transmission of this influenza strain between swine and turkeys has been documented previously.

This low pathogenic H3 virus is a milder form of virus and has not been known to mutate into high pathogenic avian influenza as the H7N3 strain did last year in the Fraser Valley. This is not related to the avian influenza outbreak in 2004 and all testing by BCMAAF to date is negative for the H5 or H7 strains of the virus.

While the CFIA and BCMAAF investigated the situation, and with the cooperation of the producer, every biosecurity measure was implemented. The CFIA is sending samples to the National Centre for Foreign Animal Diseases in Winnipeg for further testing."

While this outbreak is of a non-pathogenic strain, it illustrates how avian influenza can happen anywhere in the world and can transmit among swine and poultry. This is the inverse situation to Indonesia, where swine have apparently been infected by H5N1. Wild birds were not shown to play a major role in last year's H7N3 epizootic in the Fraser Valley, and it doesn't sound like they did in this outbreak either. This should not form a risk for humans.

A paper describing another swine - turkey transmission event is here. Papers on the previous BC outbreak are here and here