Bird flu (H5N1) in Norfolk Confirmed, November 12 +

[HenryN]

Re: Bird flu (H5N1) in Norfolk Confirmed, November 12 +

Is it correct to assume that these tests are from a sample of the 9,000 cull population? If so, how many are actually tested in order to give an acceptable level of statistical significance?

J.

I don't think you have a good grasp of the testing process. It is somewhat like dusting for fingerprints at a murder scene. If someone matches the bloody finger print, then that person was at the scene. Finger prints need not be found on every item tested.

However, the H5N1 testing goes well beyond a single test. For Weybridge to announce a positive, they would almost certainly have multiple confirmatory tests like a rapid test, and a PCR test, and a sequence from a PCR test, and an isolated virus. Moreover, in all likelihood multiple samples are positive for multiple collections from a single bird, as well as multiple birds.

Since the birds did not have clinical signs, it is unlikely that H5N1 had spread to most of the birds, and positives may have been limited to a small number of those tested (and far fewer than 9000 birds would be tested).

In addition to finding an H5N1 positive, virus grown from a sample would be sequenced and the sequence would not only show that it was influenza, but it was H5, and high path H5, and Qingahi H5N1, and Qingahi H5N1 that was cloely related to H5N1 from the earlier Redgrave positives as well as H5N1 from France, Germany, Czech Republic, Krasnodar, and Uva Lake.

The only real argument against a positve would be lab error (contamination many times by positive controls or a sample from another location).

[AlaskaDenise]

Re: Bird flu (H5N1) in Norfolk Confirmed, November 12 +

Commentary at

http://www.recombinomics.com/News/11...k_Norfolk.html

Commentary

H5N1 Spead on Suffolk and Norfolk Farms
Recombinomics Commentary
November 19, 2007

DEFRA is expected to announce confirmation of second case of avian flu on Monday afternoon.

It is understood that poultry have tested positive at one of the four farms culled as ?dangerous contacts? because of links to Redgrave Park Farm, in Suffolk, where disease was confirmed last week.

Test results on one of the farms where disease had been suspected turned out to be negative.

But tests on a second suspected case are believed to have shown the presence of the highly pathogenic H5N1 virus.

The detection of H5N1 on a second farm will significantly increase the number of farms in the protection zone. Earlier reports indicated ?preliminary? testing of dead turkeys at the Grove farm was negative. The Grove farm was within 2 miles of Redgrave Park, site of the initial outbreak (see satellite map). However, the other three suspect farms were significantly further north of the two farms with dead turkeys.

Confirmation at a second farm would likely lead to additional testing of samples from the Grove farm as well as more testing at neighboring farms and asymptomatic waterfowl.

The latest DEFRA announcement declined to specify when additional test results would be released.


.

[AlaskaDenise]

Re: Bird flu (H5N1) in Norfolk Confirmed, November 12 +

Commentary

http://www.recombinomics.com/News/11...Suffolk_2.html

Commentary

H5N1 Confirmed on Second Suffolk Farm
Recombinomics Commentary
November 19, 2007

"It appears the infection has been caught early because when the birds were inspected they appeared to be clinically healthy," she added.
Defra announced last week it was culling turkeys at four sites which shared the same workforce as the Redgrave Park farm on the border of Norfolk and Suffolk where the original case was confirmed on November 13.

Redgrave Poultry, which operates all five farms, said a small number of turkey culled at Hill Meadow farm in Knettishall, Norfolk had tested positive. The farm had 9,000 turkeys and is located just a few miles from Redgrave Park.

The company said culls had now been completed at all five farms. Results are still awaited from two of the sites.

The above comments confirm H5N1 at a second Suffolk farm, which creates a new restricted zone that extends into Norfolk. The lack of symptoms in the positive birds increases the likelihood of detecting H5N1 in the other two farms as well as adjacent farms, because the infections were recent and birds, including waterfowl, have not developed symptoms.

The sequence of the positives point toward a wild bird source because they are similar to wild bird H5N1 from the Czech Republic, Germany, France, and linked to wild bird isolates from Uva Lake in Mongolia which died during a massive outbreak in Mongolia and Tyva in the summer of 2006. Moreover, no evidence of bird flu was found at the Netherlands hatchery which had provided chicks to the owners of the infected turkeys.

Test results on the additional suspect farms, as well as neighboring farms would be useful to define the extent of the outbreak.


.

[HenryN]

Re: Bird flu (H5N1) in Norfolk Confirmed, November 12 +

Is it correct to assume that these tests are from a sample of the 9,000 cull population? If so, how many are actually tested in order to give an acceptable level of statistical significance?

J.

The official comment from DEFRA is

"Laboratory test results have today confirmed H5N1 Avian Influenza in turkeys at one of the Dangerous Contact premises."

which indicates more than one turkey had "confirmed" H5N1 indicating multiple positives on one or more turkeys.

[HenryN]

Re: Bird flu (H5N1) in Norfolk Confirmed, November 12 +

EU boosts anti-bird flu measures in Britain
(AFP)

20 November 2007



BRUSSELS - European Union nations voted Tuesday to boost measures to protect against bird flu in Britain, after two outbreaks of the potentially lethal disease were discovered there.
?Member states voted in favour of a decision reinforcing the control measures in the UK following two confirmed outbreaks of avian influenza on the border of Norfolk and Suffolk in the past weeks,? the European Commission said.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>
The decision meant that protection zones in the affected areas would be ?slightly expanded?. The measures were confirmed by the EU?s standing committee on the food chain and animal health.<o:p></o:p>
On Monday, Britain confirmed a second outbreak of the H5N1 strain of avian influenza. It was found in turkeys on premises near a first infected farm, on the border between Norfolk and Suffolk in eastern England.<o:p></o:p>
Last Tuesday authorities ordered the slaughter of more than 6,000 poultry at a site near Diss in Norfolk.<o:p></o:p>
The cull was subsequently widened to four neighbouring premises, and in all nearly 29,000 birds were slaughtered.<o:p></o:p>
Suffolk, a large poultry producing area, was hit by an outbreak of H5N1 at a turkey farm in February.<o:p></o:p>
Some 159,000 turkeys were killed as a precaution. An official report said it was most likely the virus reached the flock via imported turkey meat from Hungary.<o:p></o:p>
The H5N1 strain first emerged in Asia in 2003, and has caused some 205 deaths in humans, with Indonesia and Vietnam among the worst hit countries, according to World Health Organisation figures.<o:p></o:p>
Scientists fear that H5N1 will eventually mutate into a form that is much more easily transmissible between humans, triggering a global pandemic.<o:p></o:p>
The original source is thought to have been wild migratory birds.<o:p></o:p>
http://www.khaleejtimes.com/DisplayA...n=theworld&col=

[cartski]

Re: Bird flu (H5N1) in Norfolk Confirmed, November 12 +

I don't think you have a good grasp of the testing process.

Yes, I'll readily admit that. Basic stats courses, done years ago, with no field experience, only goes so far.

Yet I'll always reserve the right to ask questions and to attempt to learn - even if that process is taxing on the teacher. And to demand of extremely intelligent people to use their gift to explain complex matters in plain language.

It is somewhat like dusting for fingerprints at a murder scene. If someone matches the bloody finger print, then that person was at the scene. Finger prints need not be found on every item tested.

However, the H5N1 testing goes well beyond a single test. For Weybridge to announce a positive, they would almost certainly have multiple confirmatory tests like a rapid test, and a PCR test, and a sequence from a PCR test, and an isolated virus. Moreover, in all likelihood multiple samples are positive for multiple collections from a single bird, as well as multiple birds.

Since the birds did not have clinical signs, it is unlikely that H5N1 had spread to most of the birds, and positives may have been limited to a small number of those tested (and far fewer than 9000 birds would be tested).

This was very helpful. Thank you.

J.

[Shannon Bennett]

Re: Bird flu (H5N1) in Norfolk Confirmed, November 12 +

Cartski, you are in the right place but, you do need to be patient. Only a few people here have the expertise in each area we search. You have to wait for one of these rare people to find and answer your question. And, they will only do so if they have time and the desire to do so. Please remember we are all doing this on a volunteer basis. No one is getting paid for the hours of work they put in to helping others stay informed. We all want the same thing, that is to reduce the eventual morbidity and mortality associated with pandemic.

[HenryN]

Re: Bird flu (H5N1) in Norfolk Confirmed, November 12 +

Culled turkeys test negative for bird flu


By Felix Lowe and agencies

Last Updated: 6:08pm GMT 20/11/2007

<TABLE cellSpacing=0 cellPadding=0 width="100&#37;" border=0><TBODY><TR><TD>Thousands of turkeys have been culled at two farms in Norfolk in vain after it was announced that they tested negative for bird flu.
Q&A: Bird flu The birds at Stone House, in West Harling, and Bridge Farm, in Pulham, were suspected of having the disease following concerns they had "dangerous contact" with the recent outbreak of deadly H5N1 avian flu in Redgrave, Suffolk.
<TABLE cellSpacing=0 cellPadding=0 width=308 align=right border=0 hspace="0"><TBODY><TR><TD width=8 rowSpan=2></TD><TD width=300><CENTER></CENTER></TD></TR><TR><TD class=caption><CENTER> </CENTER><CENTER> </CENTER><CENTER>Almost 30,000 birds have been slaughtered since last week's initial outbreak in Redgrave

</CENTER>

</TD></TR></TBODY></TABLE>But the Department for the Environment, Food and Rural Affairs on Tuesday said initial tests on the turkeys were negative for the virus.
All the farms were operated by the same company, Redgrave Poultry, which runs Redgrave Park farm where the initial outbreak was discovered last week.
Flocks at the four "dangerous contact" farms were assessed as being at risk of having been exposed to the disease because all five sites shared the same staff.
Tests on Monday showed birds at Hill Meadow Farm in Knettishall on the Norfolk/Suffolk border had been infected with H5N1.
Another of the farms, Grove Farm, Botesdale, Suffolk, close to the first infected site, was upgraded to a slaughter on suspicion of having the disease last week after dozens of birds were found dead by officials.
But initial tests on 5,500 turkeys slaughtered found the premises was free of disease.
In all, almost 30,000 turkeys, ducks and geese have been culled in a bid to prevent the deadly virus spreading.
Protection zones and an extended surveillance zone are in place around the two infected sites, and a wider restricted zone covers Suffolk and most of Norfolk.
The blow to the poultry industry has sparked fears that prices for Christmas turkeys will go through the roof, with consumers having to pay more than &#163;200 for an organic bird.
</TD></TR></TBODY></TABLE>

http://www.telegraph.co.uk/news/main.jhtml?xml=/news/2007/11/20/nbird120.xml

[HenryN]

Re: Bird flu (H5N1) in Norfolk Confirmed, November 12 +

<TABLE cellSpacing=0 cellPadding=0 width=629 border=0><TBODY><TR><TD colSpan=3>Bird flu cull farms not infected

</TD></TR><TR><TD vAlign=top width=416><!-- S BO --><!-- S IIMA --><TABLE cellSpacing=0 cellPadding=0 width=203 align=right border=0><TBODY><TR><TD> More than 28,000 birds have been culled

</TD></TR></TBODY></TABLE><!-- E IIMA --><!-- S SF -->Turkeys culled at two farms over fears of exposure to bird flu have tested negative for the deadly H5N1 strain.
Birds at Stone House in West Harling and Bridge Farm in Pulham, both in Norfolk, were judged to have been in "dangerous contact" with the disease.
The farms are run by Redgrave Poultry, the owner of two farms in Norfolk and Suffolk, where H5N1 has been confirmed. Tests on culled birds at a fifth premises - Grove Farm, in Botesdale, Suffolk - indicate it was disease-free. <!-- E SF -->
In all, more than 28,000 turkeys, ducks and geese have been culled in a bid to prevent the deadly virus spreading.
Protection zones and an extended surveillance zone are in place around the two infected sites, with a wider restricted zone covering Suffolk and most of Norfolk.
<!-- S IINC --><TABLE cellSpacing=0 cellPadding=0 width=203 align=right border=0><TBODY><TR><TD width=5></TD><TD class=sibtbg>
Locations of H5N1 outbreaks and precautionary culls.

Enlarge Map

</TD></TR></TBODY></TABLE><!-- E IINC -->
The H5N1 outbreak was first confirmed at Redgrave Park Farm, in Redgrave, near Diss, on the Norfolk/Suffolk border, a week ago.
Birds at four other farms were considered to have been in dangerous contact with the outbreak because they had staff members in common with the affected farms.
On Monday, it was confirmed the culled birds at Hill Meadow Farm in Knettishall on the Norfolk/Suffolk border had been infected with H5N1.
Grove Farm, Botesdale, Suffolk, close to the first infected site, was upgraded to a slaughter on suspicion of having the disease last week after dozens of birds were found dead by officials.
But initial tests on 5,500 turkeys slaughtered found the premises was free of disease.
A new 3km protection zone around the Hill Meadow Farm case has been established and a wider surveillance zone covering both sites has also been imposed. A national and a local disease control centre have been established in Bury St Edmunds, with text messages sent to all bird keepers nationwide - especially those in zones on the poultry register. The cost of animal infections is thought to have cost the government and taxpayer more than ?120m this year.

http://news.bbc.co.uk/2/hi/uk_news/7104572.stm

</TD></TR></TBODY></TABLE>

[HenryN]

Re: Bird flu (H5N1) in Norfolk Confirmed, November 12 +

Call to stay alert as bird flu zone grows



<TABLE id=google_tb1 style="MARGIN-TOP: 3px; BORDER-LEFT-COLOR: #cccccc; MARGIN-BOTTOM: 5px; BORDER-BOTTOM-COLOR: #cccccc; MARGIN-LEFT: 0px; BORDER-TOP-COLOR: #cccccc; BORDER-RIGHT-COLOR: #cccccc" borderColor=#cccccc align=left bgColor=#ffffff border=0><TBODY><TR align=left><TD style="PADDING-LEFT: 0px; PADDING-BOTTOM: 5px; WIDTH: 130px"><SCRIPT type=text/javascript><!--google_ad_client = "pub-2643863077864284";google_ad_width = 125;google_ad_height = 125;google_ad_format = "125x125_as";google_ad_type = "text";google_color_border = "FFFFFF";google_color_bg = "FFFFFF";google_color_link = "000000";google_color_text = "000000";google_color_url = "000000";//--></SCRIPT><SCRIPT src="http://pagead2.googlesyndication.com/pagead/show_ads.js" type=text/javascript></SCRIPT></TD></TR></TBODY></TABLE>BIRD flu restrictions have been extended to Newmarket following the confirmation of a second outbreak of the deadly H5N1 - more than 30 miles from the town.
Restrictions on poultry movements were extended to cover the whole of Suffolk and much of Norfolk on Monday after the strain of bird flu was confirmed at a farm at Knettishall, near Diss, where a precautionary cull of turkeys had already taken place.
Signs went up on roads around Newmarket and Mildenhall after Defra, the Department for Environment, Food and Rural Affairs, extended the zone on Monday.
Poultry farmers within the restricted zone, which extends as far as Shippea Hill on the A1101 near Littleport, have been warned to prevent contact with wild birds.
They are also banned from sending their birds, waste poultry litter, manure or slurry out of the zone. Birds can still be sent for slaughter within the control zone.
Restrictions also apply to wild game products which cannot move out of the zone and cannot be exported.
Licences are needed for some movements of poultry and eggs.
Fred Landeg, acting chief veterinary officer, said: "The laboratory test results (which confirmed the second outbreak) highlight the importance of poultry keepers in the area being extremely vigilant.
"It is essential they practice the highest levels of biosecurity and report any suspicions of disease to their local animal health office."
Police have warned community groups about the restrictions through the Police Direct link system.
Suffolk County Council is also involved in informing residents and businesses in the area. The council has also said that any dead ducks, geese, swans and waders found in the zone should be reported.
For more details log onto Defra's website at www.defra.gov.uk or Suffolk County Council's website at www.suffolk.gov.uk



<TABLE width="100&#37;"><TBODY><TR><TD></TD><TD noWrap align=right>21 November 2007

</TD></TR></TBODY></TABLE>

http://www.cambridge-news.co.uk/news/newmarket/2007/11/21/450d6326-be28-4fa4-9d49-a3b941aeecf7.lpf

[canagica]

Re: Bird flu (H5N1) in Norfolk Confirmed, November 12 +

Yes, I'll readily admit that. Basic stats courses, done years ago, with no field experience, only goes so far.

Yet I'll always reserve the right to ask questions and to attempt to learn - even if that process is taxing on the teacher. And to demand of extremely intelligent people to use their gift to explain complex matters in plain language.

This was very helpful. Thank you.

J.

Hey Cartski-
It's actually a great question to be asking in regards to going beyond a presence/absence understanding of the current outbreak, and attempting to gain information about the epidemiology of the outbreak.

For example, if the entire flock wasn't showing clinical signs, but was infected, that might suggest one route of infection into the flock that could quickly and uniformly affect them all (e.g., contaminated feed, widespread, constant overlap with infected wild birds, persistent uniform environmental contamination). On the other hand, if only a very small number of birds were infected, and the rest were not, it might suggest a different transmission route (say, a chance encounter with an infected wild bird, or a single improperly washed transport cage, etc.). Neither of these outright tells you what happened, but it can be used to support or negate support for a given route of transmission.

Over time we would expect the entire flock to become infected, which is the likely reason why culls are based on presence/absence, but, as I started out saying, your question is still an appropriate one if the ultimate goal is to better understand how the disease is being transmitted.

I would argue that this understanding would be nearly essential to assigning probabilities to various potential routes of transmission, and therefore assessing risk for a given area.

[HenryN]

Re: Bird flu (H5N1) in Norfolk Confirmed, November 12 +

Hey Cartski-
It's actually a great question to be asking in regards to going beyond a presence/absence understanding of the current outbreak, and attempting to gain information about the epidemiology of the outbreak.

For example, if the entire flock wasn't showing clinical signs, but was infected, that might suggest one route of infection into the flock that could quickly and uniformly affect them all (e.g., contaminated feed, widespread, constant overlap with infected wild birds, persistent uniform environmental contamination). On the other hand, if only a very small number of birds were infected, and the rest were not, it might suggest a different transmission route (say, a chance encounter with an infected wild bird, or a single improperly washed transport cage, etc.). Neither of these outright tells you what happened, but it can be used to support or negate support for a given route of transmission.

Over time we would expect the entire flock to become infected, which is the likely reason why culls are based on presence/absence, but, as I started out saying, your question is still an appropriate one if the ultimate goal is to better understand how the disease is being transmitted.

I would argue that this understanding would be nearly essential to assigning probabilities to various potential routes of transmission, and therefore assessing risk for a given area.

Since second H5N1 positive farm employed the same workers, it is likely that one of the workers intodruced H5N1 into the farm, and the introduction was recent.

[HenryN]

Re: Bird flu (H5N1) in Norfolk Confirmed, November 12 +

<TABLE cellSpacing=0 cellPadding=0 width=629 border=0><TBODY><TR><TD colSpan=3>Fifth bird flu cull launched


</TD></TR><TR><TD vAlign=top width=416><!-- S BO --><!-- S IIMA --><TABLE cellSpacing=0 cellPadding=0 width=203 align=right border=0><TBODY><TR><TD> More than 28,000 birds have been culled


</TD></TR></TBODY></TABLE><!-- E IIMA --><!-- S SF -->Poultry on a fifth farm near the Norfolk-Suffolk border are to be culled in a bid to control the current outbreak of bird flu, officials say.
DEFRA officials say the latest cull falls within the existing surveillance zone where the deadly H5N1 strain was first suspected on 15 November. Acting Chief Veterinary Officer Fred Landeg said the move is based on new information about an exposure risk. He stressed that all poultry keepers must report any signs of the disease. <!-- E SF -->

</TD></TR></TBODY></TABLE>

http://news.bbc.co.uk/2/hi/uk_news/7106304.stm

[HenryN]

Re: Bird flu (H5N1) in Norfolk Confirmed, November 12 +

Poultry cull over bird flu fear


Poultry at a sixth site is being culled amid bird flu fears



Poultry on a sixth premises are being culled on suspicion of bird flu, the Department for the Environment, Food and Rural Affairs (Defra) said.
The premises, within the existing surveillance zone, and just outside the original 3km protection zone, have been designated a dangerous contact site.

The birds are being culled as a precautionary measure, Defra said.

The latest premises, in Suffolk, is the fifth to be declared a "dangerous contact" site, and the sixth in total to have poultry culled, including the original infected site.

A total of 56,000 ducks, 9,000 turkeys and 3,000 geese have been culled at the latest premises.

It is operated by the same company Redgrave Poultry, which runs the other four "dangerous contact" sites and Redgrave Park farm where the initial outbreak was discovered.

The latest cull is in line with contingency plans and a veterinary assessment of the risk, Defra said.

Acting Chief Veterinary Officer Fred Landeg said: "This decision has been taken based on new information which indicates the possibility that the poultry on this premise may have been exposed to infection.

"I can not emphasise enough that it is essential all poultry keepers practice the highest levels of biosecurity and report any suspicions of disease to their local Animal Health office."

The national ban on bird gatherings remains in place, and movement restrictions apply in the protection, surveillance and restricted zones, Defra said. Bird keepers in these zones are required to house or otherwise isolate their birds from wild birds.

http://www.pendletoday.co.uk/latest-national-news/Poultry-cull-over-bird-flu.3511107.jp

The full article contains 273 words and appears in Press Association newspaper.
Last Updated: 21 November 2007 5:35 PM

[HenryN]

Re: Bird flu (H5N1) in Norfolk Confirmed, November 12 +

Poultry cull over bird flu fear



Acting Chief Veterinary Officer Fred Landeg said: "This decision has been taken based on new information which indicates the possibility that the poultry on this premise may have been exposed to infection.

"I can not emphasise enough that it is essential all poultry keepers practice the highest levels of biosecurity and report any suspicions of disease to their local Animal Health office."

The national ban on bird gatherings remains in place, and movement restrictions apply in the protection, surveillance and restricted zones, Defra said. Bird keepers in these zones are required to house or otherwise isolate their birds from wild birds.

http://www.pendletoday.co.uk/latest-national-news/Poultry-cull-over-bird-flu.3511107.jp

The full article contains 273 words and appears in Press Association newspaper.
Last Updated: 21 November 2007 5:35 PM

The above comment on exposure is rather cryptic since it does not specifically state that the exposure is a shared worker.

Well into a thickening plot category.