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China bird flu effort in question after additional cases in 2009

Giuseppe

Emeritus
AFP: China bird flu effort in question after new cases

China bird flu effort in question after new cases

HONG KONG (AFP) ?

A probe into an outbreak of bird flu at a Hong Kong chicken farm and carcasses popping up in city waters have raised questions over whether the H5N1 virus is going undetected in southern China.


The report released this month said wild birds were the most likely carriers of the virus that broke out in December on a farm close to the territory's border with the southern Chinese province of Guangdong, prompting the culling of 90,000 chickens.

While the authors could not say for certain where in Asia the wild bird may have contracted H5N1, the report said the specific version of the virus was the same as that "currently circulating among poultry in southern China".

The report came days after two dead chickens with H5N1 were found floating in the sea off Hong Kong, the latest of more than a dozen chickens, ducks and other birds to wash up along the city's coastline since the start of year.

"From the various investigations we have done (the washed-up carcasses) are most likely drifting down from the Pearl River," Hong Kong's health secretary York Chow said in early February.

Hong Kong sits at the southern tip of a Guangdong's large Pearl River delta.

Malik Peiris, a virologist at Hong Kong University and one of the world's leading bird flu researchers, said he agreed with Chow's assessment.

"It is not really plausible that they came from Hong Kong," he told AFP.

While Hong Kong has publicly confirmed 15 bird flu cases this year in addition to the December outbreak on the poultry farm, Guangdong has posted no bird flu findings since June 2008.

"Up to now we have no explanation as to why (bird carcasses have appeared), from the mainland authorities. This is a cause for concern," said Lo Wing-lok, a member of Hong Kong's government scientific committee on emerging diseases.

Peter Cordingley, the Asia-Pacific spokesman for the World Health Organisation, said the appearance of the dead birds was an issue of concern.

"From a public health point of view we are concerned about South China," he said, adding that Hong Kong's surveillance systems for outbreaks in humans and poultry was the "international gold standard".

A spokesman for China's health ministry declined to comment.

In early February, a grey heron was found dead in boggy water at the Mai Po nature reserve within sight of the border.

The heron tested positive for H5N1, the first at the reserve since testing began in 2003, shifting the focus onto the role of wild birds in the spread of the disease.

This was reinforced by the poultry outbreak investigation that found wild birds the "most likely" carrier.

But most experts believe wild birds cannot explain the prevalence of the disease in the region.

"The wild birds are more like canaries in a coal mine (for infected poultry)," said Martin Williams, a bird expert and environmental activist.

Peiris said that although the role of wild birds in the spread of the virus needed to be studied, intensive farming should be the main focus.

"Poultry production and the movement of poultry are probably far more important as the route of the maintenance and dissemination of these viruses," said Peiris.

Scientists are concerned that poultry farms act as an ideal breeding ground for the virus to mutate as so many carriers are in close proximity.

H5N1 has killed more than 250 people worldwide since 2003 -- and also led to the culling of millions of chickens -- but scientists' deepest fear is that a pandemic killing millions could be triggered if the virus mutated to become easily transferable between humans.

And so any outbreak must be reported quickly.

"Controlling the poultry outbreak, I would say, is the most important element in the overall control of H5N1," said Lo.

While no H5N1 reports have come out of Guangdong this year, eight people elsewhere in the mainland are known to have caught the virus, and five of them have died.

Seven of the eight had known close contact with poultry, but despite extensive testing -- praised by the Food and Agriculture Organisation -- only one poultry outbreak has been found, in the northwestern province of Xinjiang.

"Human cases have become increasingly difficult not to report," Lo said.

However "we always ask the question, when human cases are reported, where is the source of the infection?"

Copyright ? 2009 AFP. All rights reserved.
-
<cite cite="http://www.google.com/hostednews/afp/article/ALeqM5issJkxpNXrETgztMOpoai2VsGU7A">AFP: China bird flu effort in question after new cases</cite>
 
Re: China bird flu effort in question after new cases

Re: China bird flu effort in question after new cases

hat tip Senior Moderator Fla Medic -


The Winter Of Our Disbelief



# 2900





Hong Kong lies at the mouth of the Pearl River Delta. The Pearl River, as you can see from the map above, is fed by many tributaries flowing out of Guangdong Province, China.

A closer view shows Hong Kong and the New Territories at the outflow of the Pearl River.




Over the past two months more than a dozen H5N1 infected birds, mostly ducks and chickens, have washed up on the beaches of Lantau and other islands in Hong Kong.

Since these birds appeared in areas far removed from any local poultry operations ? and given the level of decomposition of the birds ? it is reasonable to assume they were discarded into the Pearl River, or one of its tributaries somewhere in Guangdong Province.
Additionally, Hong Kong continues to occasionally find dead migratory birds, also H5N1 infected, that likely came from the mainland.

Chinese officials, however, continue to insist that there has been no outbreak of H5N1 in Guangdong Province. They have also denied outbreaks in other provinces as well (other than one in the northwestern province of Xinjiang).
Other sources of information, however, would suggest otherwise.

On the 3rd of March, Reuters reported that bird flu had exacted a heavy toll on poultry operations in China.

Bird flu, rural downturn ravage China poultry numbers

Tue Mar 3, 2009 4:42am GMT
By Niu Shuping and Tom Miles
BEIJING, March 3 (Reuters) - The impact of bird flu and the economic slowdown may have cut China's poultry numbers by about a third or more in the last month, executives in the poultry feed industry said on Tuesday.
<snip>
The executive said many chicken slaughter houses were closed, including half of those in the largest poultry producing province of Shandong, mainly because of outbreaks of bird flu.
Last Tuesday, we get this report from the Beijing Times, saying all live poultry markets would be closed in medium-sized and large cities across china.

Live poultry markets to be shut to prevent spread of Avian influenza.

The Sina news portal has a headline news story about plans to shut live poultry markets in all large and medium-sized cities throughout China, to prevent the spread of Avian flu.
Hours later, the Minister of Agriculture (MOA) of China denies the report. It appears that this was a proposal under consideration ? but not a fait accompli ? and someone leaked it to the press.

Dissident Media sources have reported massive outbreaks of bird flu in both Jiangsu Province and Wuhan, over the past 3 months.
And mainstream news organizations have openly questioned the official Chinese story of `no bird flu outbreaks?.

This report is from Time Magazine.


Is China Making Its Bird-Flu Outbreak Worse?

By Austin Ramzy / Beijing Friday, Feb. 13, 2009
birds_0213.jpg

Farmers prepare to bury dead chickens on Feb. 5 in Chongqing, China, where since Jan. 30 nearly 12,000 chickens have been found dead in a local village. The cause of the deaths is still not determined
You can find more coverage on these, and other reports, in the following blogs:

This morning we get a rather long article from AFP (Agence France-Presse) which once again asks the question:

Just what is going on in China?

First some excerpts from this report, then some more discussion. By all means, follow the link to read the entire article.

I?ll wait.



China bird flu effort in question after new cases
<cite>by John Saeki John Saeki </cite>? <abbr>Sat Mar 14, 11:28 pm ET</abbr>
<cite></cite>
HONG KONG (AFP) ? A probe into an outbreak of bird flu at a Hong Kong chicken farm and carcasses popping up in city waters have raised questions over whether the H5N1 virus is going undetected in southern China.

The report released this month said wild birds were the most likely carriers of the virus that broke out in December on a farm close to the territory's border with the southern Chinese province of Guangdong, prompting the culling of 90,000 chickens.

While the authors could not say for certain where in Asia the wild bird may have contracted H5N1, the report said the specific version of the virus was the same as that "currently circulating among poultry in southern China".
<snip>

Peter Cordingley, the Asia-Pacific spokesman for the World Health Organisation, said the appearance of the dead birds was an issue of concern.

"From a public health point of view we are concerned about South China," he said, adding that Hong Kong's surveillance systems for outbreaks in humans and poultry was the "international gold standard".

A spokesman for China's health ministry declined to comment.
The report mentioned in this article is a 47 page, highly detailed epidemiological report issued by the University of Hong Kong, on the outbreak of H5N1 on a solitary chicken farm in the New Territories last December.


The question of how a single farm could become infected with the H5N1 virus was addressed on page 3 & 4 of the report. The most likely source, they believe, was from wild migratory birds.



(1) Introduction of virus into farm

(i) The virus could have been introduced to the farm by droppings of infected wild birds given the presence of aquatic birds and other birds on and around the farm and the presence of trees on the farm and uncovered soak away pits that are attractive to birds, including large aquatic species (herons and egrets).
Part of the aisle of the infected shed no. 17, although covered by bird protection nets, was under some branches of the trees near its entrance. This design of the shed could have allowed the droppings of wild birds to contaminate the exposed area inside the shed.

(ii) The strong winds and gust from the north and north-east from 4 to 6 December 2008 could have deposited potentially contaminated dust and leaves from the trees into the nearby shed no. 17 via its north opening. These contaminated materials could then have gathered at the corner of the shed where the initial high mortality in poultry occurred.

(iii) Introduction of the virus from outside the farm through contaminated fomites or people is considered less likely.

(iv) Introduction of the virus from drinking water can be ruled out as all chickens are supplied with reticulated water.
This is a diagnosis of exclusion, of course.


Researchers basically eliminated the other possibilities, and were left with migratory birds as the most plausible explanation.

Birds that most likely came from Guangdong Province, China.

Over the past few months we?ve seen openly contradictory statements by the Chinese Minister of Health (MOH) and the Chinese Minister of Argriculture (MOA) over the source of infection of the 7 admitted human cases in January.

The MOH insists that nearly all had direct contact with poultry, and that was the likely source of infection. The MOA insists that the country?s poultry is free of the virus.

Both can?t be right.

In February Zhong Nanshan, a hero of the SARS outbreak and a highly respected respiratory disease specialist, warned that vaccinated poultry can still become infected with the H5N1 virus.


Chinese expert issues new bird flu warning
www.chinaview.cn
space.gif
2009-02-06 17:59:50


GUANGZHOU, Feb. 6 (Xinhua) -- A leading Chinese expert on respiratory diseases has warned the public to be aware that poultry can be infected with the bird flu virus but show no symptoms.


"Special attention should be paid to such animals, including those that have been vaccinated," said Zhong Nanshan.

"The existing vaccines can only reduce the amount of virus, rather than totally inactivating it," he said.

Over the past couple of months we?ve seen some of the biggest names in public health out of Hong Kong (and some mainland China) openly questioning the official Chinese story.

Some recent quotes plucked from news reports over the past couple of months include:

"The human cases show the virus must be circulating among birds," Vincent Martin, a senior technical advisor on avian flu for the FAO, told Bloomberg.

Dr Hans Troedsson, WHO Representative in China stated :"The fact that this is the highest number (of human infections) for a single month in China reminds us that the virus is entrenched and circulating in the environment.?

Dr. Lo Wing-Lok, a communicable disease expert from Hong Kong, stated "There's no doubt of an outbreak of bird flu in China, though the government hasn't admitted it."

"From the various investigations we have done (the washed-up carcasses) are most likely drifting down from the Pearl River," Hong Kong's health secretary York Chow said in early February.
And you can add in the voices of such notables as Malik Peiris, Robert Webster, and Guan Yi to the growing chorus of concern over bird flu flying under the radar in China.

Assuming these respected scientists are right, the problem in China appears two-fold.

First, wild (mostly aquatic) birds apparently continue to harbor the H5N1 virus - probably without ill effect ? and serve as an ongoing vector to the domestic poultry in that country.

Second, vaccinated poultry may acquire the infection without showing symptoms due to the partial protection afforded by the poultry vaccines in use. Healthy appearing poultry can therefore pass the virus on to other birds, and on rare occasions, to humans as well.
The OIE (World Organization For Animal Health) recently reaffirmed their long-standing position that vaccination of poultry cannot be considered a long-term solution to combating the avian flu virus.

In Avian influenza and vaccination: what is the scientific recommendation?, the OIE reiterates their strong recommendation that humane culling be employed to control avian influenza, and advising that vaccines should only be used as a temporary measure.

While the OIE concedes that some nations may require the use of vaccines for `several years', they strongly urge that countries move away from that program and towards the more conventional culling policy.

They call this shift away from vaccines an `Exit Strategy?, something which China has shown no move towards.

For the Minister of Agriculture, who is responsible for the largest poultry production on earth (estimated at 15 billion birds), having a silent but (potentially) deadly virus circulating among the nation?s poultry industry has to be nothing short of a nightmare.

Poultry is one of the few relatively inexpensive, and readily available, sources of protein for his country of 1.3 billion people. Massive culling to rid themselves of the infection would be a drastic, and very unpopular, course of action.

It could even be politically destabilizing.

While it is unclear exactly how pervasive asymptomatic H5N1 might be in China?s poultry, the reports we keep getting suggest the problem is growing worse.

Meanwhile, the silence out of China on what is going on remains deafening.
 
Re: China bird flu effort in question after new cases

Re: China bird flu effort in question after new cases

Thanks to Fla Medic for that study link; it was most interesting.

the 2 kittens and dogs were never in the barns and tested negative.
the water tested negative
the sanitary controls were somewhat lax
none of the workers appeared to have been exposed elsewhere
the waste collection truck was sanitized, as was the ground it drove over
no signs of smuggling
no signs of illegally kept poultry in surrounding farms
the bird catcher was an unlikely spreader
rodents were observed but not tested (Please test the rodents!!)
the farm was inspected once a week

Since the farm is close to the coastline of Deep Bay and within 3 km of the Wetland Park, where migratory birds gather, aquatic bird activities around the index farm are not unexpected.

In fact, aquatic birds were found on the farm during the investigation visits at a time when there were no poultry on the farm. Two little egrets (Egretta garzetta) were found roosting in a tree on top of the entrance of shed no. 17 on 16 December 2008 and five or six Chinese pond herons (Ardeola bacchus) were seen seeking food at the uncovered soak-away pits on 18 December 2008.

A total of 2 538 swab samples (from 1 530 sentinels and 1 008 vaccinated chickens) were collected from 29 farms after the outbreak and all tested negative for the H5 virus. (apparently no infection from the wild birds on any of the other surrounding farms)

According to the meteorological records provided by the Hong Kong Observatory, there were strong winds and gust from the north and north-east from 4 to 6 December 2008. The north wind could have carried potentially contaminated dust particles from outside the shed and blown them into the infected shed no. 17. The slope beside shed no. 17 would likely alter the course of the north-east wind allowing it to then change direction to north-west. The new course of the wind might have also blown potentially contaminated dust and leaves into the shed where they would accumulate in the part of the shed which experienced the highest mortality. (they referred to a Canadian study and, unlike the Canadians, are taking into account wind direction changes)

wild birds tested negative

A total of 17 environmental swabs and wild bird fecal samples were collected from the index farm on 17 and 18 December 2008. All samples tested negative for the H5 virus

The role of sparrows in the carriage and transmission of H5N1 HPAI viruses has been investigated in Hong Kong and elsewhere. One H5N1 virus positive dead sparrow was detected in Kowloon Park in early 2003 at a time when infection was present in the zoological collection in that park but no positive dead sparrows have been found in Hong Kong subsequently despite intensive surveillance since October 2005.

In total over 3 000 dead sparrows have been tested from October 2005 to December 2008 with none testing positive for the H5N1 avian influenza virus.

Experimental studies with the original H5N1 isolates from Hong Kong in 1997 demonstrated that sparrows were relatively resistant to infection. However a recent experimental study demonstrated that tree sparrows can be infected with and excrete (for a short period of time) a range of recent H5N1 HPAI viruses after inoculation with a large dose of the virus. This study included two isolates from dead birds from Hong Kong (both Clade 2.3.4 viruses isolated from dead wild birds in 2006). Five of the six sparrows infected with these Hong Kong viruses died within 6 days of being infected. However, under the conditions of the experiment, transmission from infected to in-contact sparrows did not occur.

H5N1 HPAI viruses were isolated from four out of 38 captured tree sparrows in Henan Province in 2004. The viruses isolated from these sparrows belonged to Clades (Clades 6 and 7) different to those found so far in Hong Kong.

Based on the above it is apparent that sparrows have the potential to excrete H5N1 HPAI viruses at least for a few days if infected but the absence of positive results from recent dead bird surveillance suggests that infection of these birds occurs infrequently in Hong Kong.

It is also theoretically possible for wild birds to act as mechanical carriers of contaminated material into poultry sheds but this has never been proved as a source of infection in any other outbreaks.
 
Re: China bird flu effort in question after new cases

Re: China bird flu effort in question after new cases

the Henan sparrows had interesting sequences, close to the
bird-index with recombinations an preservations.
I think it would be interesting to examine
how they got it.

A repitition of the Henan study would be useful,
examining sparrows for any flu-viruses


http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1316012/


A survey of epidemic avian influenza virus in
tree sparrows was conducted in Pingyu country
in the Henan province of China in May 2004.
Cloacal swabs were collected from 38 captured free-living tree sparrows
 
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