Dossier AI Transmission: Modelling the Wind-Borne Spread of Highly Pathogenic Avian Influenza Virus between Farms

The mechanisms of HPAI virus spread between farms are poorly understood; it has been hypothesized that the indirect between-farm contacts play a role [9,14–17].

The frequency and the transmission effectiveness of these contacts determine their virus transmission rates. Here we perform a quantitative assessment of the contribution of indirect contacts to the spread of the virus between farms during the 2003 HPAI epidemic in the Netherlands.

During this epidemic, potentially infectious contacts to both infected and escaping farms were traced. In this paper, the collected data is used to quantify the per-contact probability of virus transmission between farms.

A quantitative understanding of the spread of contaminated farm dust between locations is a prerequisite for obtaining much-needed insight into one of the possible mechanisms of disease spread between farms.

A model was developed to calculate the quantity of contaminated farm-dust particles deposited at various locations downwind of a source farm and apply the model to assess the possible contribution of the wind-borne route to the transmission of Highly Pathogenic Avian Influenza virus (HPAI) during the 2003 epidemic in the Netherlands.

The model is obtained from a Gaussian Plume Model by incorporating the dust deposition process, pathogen decay, and a model for the infection process on exposed farms. Using poultry- and avian influenza-specific parameter values we calculate the distance-dependent probability of between-farm transmission by this route.

A comparison between the transmission risk pattern predicted by the model and the pattern observed during the 2003 epidemic reveals that the wind-borne route alone is insufficient to explain the observations although it could contribute substantially to the spread over short distance ranges, for example, explaining 24% of the transmission over distances up to 25 km.

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Dossier AI Transmission: David Stallknecht doubts the role migratory birds spreading AI

The question what causes the current outbreaks in Minnesota is heavily discussed, especially the role of migratory birds. USDA APHIS tends to the opinion that migratory birds play an important role. In that case, H5N2 will likely remain a threat to U.S. poultry for three to five years, Olson said, citing information from wildlife experts. That is how long it will take wild birds to develop immunity to the disease. Since the beginning of the year, the flu, which can kill nearly an entire poultry flock within 48 hours, has also been found in birds from Oregon to Arkansas. The discoveries have prompted major overseas buyers such as Mexico and Canada to limit imports of U.S. poultry and companies such as Tyson Foods Inc to strengthen measures to keep the disease off farms.

The number of infections is climbing as migratory ducks, which are believed to be spreading the disease, return to Minnesota to breed after spending the winter farther south, said Beth Thompson, assistant director of the Minnesota Board of Animal Health. The larger number of ducks likely increases the risk for wild birds to transmit the virus.

Farm workers are probably infecting turkeys by tracking the virus into barns after stepping in contaminated duck feces, said John Glisson, vice president of research for the U.S. Poultry and Egg Association. Chicken flocks are also vulnerable. “Minnesota is a real hotbed for returning waterfowl,” Glisson said. The USDA has said it believes migratory ducks are spreading the flu and sent a team to Minnesota to determine how it is moving into poultry flocks. So far, efforts to stop the spread by controlling human and vehicle traffic on farms have not worked.

The number of infections may continue to rise through mid-May, when spring migration ends, said Steve Olson, executive director of the Minnesota Turkey Growers Association. New cases may accelerate again in the autumn when recently hatched ducks, which have never been exposed to the virus, begin migrating south, he added.

In the absence of reliable epidemiological data about the spreading under wildfowl population, the source of infection will continue to spark speculations about the role of migratory birds.

Despite all evidence, there are scientists who have reason to doubt the thesis that migratory birds are to blame, like Professor David Stallknecht from University of Georgia’s College of Veterinary Medicine. David is openly questioning the USDA’s conclusion. David Stallknecht called the notion that avian flu originated in wild birds “pure speculation” in a story posted by the University of Minnesota’s Center for Infectious Disease Research and Policy (CIDRAP).

David Stallknecht: “It is based on circumstantial evidence that is rapidly becoming accepted dogma. The avian flu saga dates back to late last year, when H5N2 struck several farms in British Columbia. That sparked surveillance programs in the U.S., which turned up cases of pintail duck virus in Washington and a related strain in a captive gyrfalcon nearby. Since then, cases of H5N2 have shown up in poultry in several states, including Idaho, Minnesota and Arkansas.”

In order to stop large-scale outbreaks, more efforts have to be undertaken to protect commercial flocks and to predict future outbreaks. Even more reasons to increase the active surveillance efforts, including the crucial active surveillance programs under wild birds, like Stallknecht suggests.

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Dossier Anoxia: N2GF equipment commercially available in Benelux and Germany

Marking March 31 2015 as the official launching date, the First series of Anoxia Foam systems that will be officially branded as N2GF equipment is now commercially available in Netherlands, Belgium and Germany.

Anoxia Foam is a new and promising technique to euthanize farm animals with less negative impact on animal welfare. This was the conclusion of the veterinarians participating in the first course on Anoxia technology that was held last February in Barneveld, Netherlands. The Anoxia Foam technique consists of stunning animals in nitrogen gas foam, causing loss of consciousness within 20 – 30 seconds without stress. Poultry vets from Netherlands, Belgium and Germany joined the training that was accredited by the Royal Dutch Society of Veterinary Science.

N2GF systems consist of a high-expansion foam nozzle, fed with nitrogen from a high-pressure gas cylinder or from a nitrogen generator that produces nitrogen on the spot. The nitrogen generator has been specifically designed for use in a poultry house atmosphere by Parker Hannifin, the world leading company in this area.

The N2GF systems are now launched by Anoxia Europe BV in the Netherlands, Belgium and Germany (Lower Saxony and Nord Rhine-Westphalia). Anoxia Europe will be coordinating development of the N2GF technique in consultation with veterinary authorities and will be sharing best practices across Europe. Certified veterinarians will support a proper use of the N2GF system to safeguard animal welfare, in implementation of the relevant EU Regulation 1099/2009.

40 complete N2GF systems will be tested in everyday practice on a variety of poultry farms for stunning and euthanizing of parent stock, turkeys, ducks, layers and broilers. For a special introductory offer, see

For more information contact Dr Michiel van Mil, Anoxia Europe, at or +31-3417016876

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Dossier AI: Global Poultry Outlook Upbeat

Rabobank has published a new report on the global poultry industry, looking at the impact of avian influenza outbreaks across the sector. In the report, Rabobank’s Food & Agribusiness Research team says that pressure from the avian influenza (AI), or bird flu, is further spreading across the globe, with new outbreaks in Asia, Europe and North America.

Rabobank Animal Protein Analyst, Nan-Dirk Mulder, said: “Avian flu is further spreading across the globe and could affect global trade streams, especially as the virus has moved further in Europe to Hungary, and in the US to central states like Minnesota, Missouri and Arkansas. “Joint global approaches, optimal biosecurity, and strong monitoring and compensation systems are necessary to stop the spread of the disease,” he added

Global Outlook

The margin outlook for the global poultry industry remains upbeat, with continuing bullish drivers like high beef prices, lower feed costs and relatively strong demand in most regions.

Global trade is under pressure from the AI outbreaks. The exchange rate volatility and turmoil in regions such as the Middle East and Eastern Europe, are leading to lower trade volumes, prices and shifts in trade streams.

United States
The poultry sector in the US has a favourable outlook but some uncertainties remain. The margins are expected to remain high in 2015. The biggest unknown in 2015 is industry expansion.

The Brazilian poultry market began 2015 bullish despite of the export challenges. The lower oil price will hit the Middle East demand. Still, exports are expected to be strong in 2015, mostly driven by Asia. Margins will be supported by a reduction in feed costs as well.

The EU poultry industry shows some recovery and, although supply is currently tight, the outlook is threatened by ongoing avian flu concerns and still closed export markets.

Entering the first quarter of 2015, China has an ongoing struggle of oversupply due to AI and food safety issues. As a consequence of human AI cases reported, live bird markets were shut down. During the seasonal peak month, poultry retail prices remained flat.

The Russian market remains very bullish on low supply. The outlook remains strong, with expected ongoing tight market conditions due to expensive, limited imported volumes and restrictions on growth.

Other Regions
Mexico has ongoing AI issues and lower pork prices will soften poultry meat consumption growth.
Japan’s poultry industry is still bullish despite ongoing AI outbreaks.
In Thailand, the export position is supported by a strong Thai baht.

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Dossier H5N8 in the USA: Update on Avian Influenza Findings in the Pacific Flyway

The United States Department of Agriculture has confirmed several findings of highly pathogenic avian influenza (HPAI) in the Pacific flyway since mid-December. The first commercial poultry detection [JRH1] was in a turkey flock in California on January 23. USDA considers this finding to be part of the ongoing avian influenza disease incident. Commercial poultry producers follow strict biosecurity practices and raise their birds in very controlled environments. There is no immediate public health concern as a result of these detections.

Poultry Findings confirmed by USDA’s National Veterinary Services Laboratories Include:

Captive Wild Bird Findings Confirmed by USDA’s National Veterinary Services Laboratories:

Wild Bird Findings confirmed by USDA’s National Veterinary Services Laboratories are available here.

Surveillance for avian influenza is ongoing in commercial poultry operations, live bird markets, and in migratory wild bird populations.
USDA is coordinating closely with its partners, including Washington, Oregon and California, Nevada, Utah, and Idaho State officials, the U.S. Department of the Interior and the U.S. Department of Health and Human Services, on avian influenza surveillance, reporting, and control efforts. The United States has the strongest AI surveillance program in the world, where we actively look for the disease and provide 100% compensation to affected producers to encourage reporting.
USDA continues to report these findings to the World Animal Health Organization (OIE) as part of the ongoing Pacific Flyway avian influenza incident. USDA is working with trading partners to minimize trade impacts on poultry and poultry products as much as possible.
All bird owners, whether commercial producers or backyard enthusiasts, need to continue practicing good biosecurity, preventing contact between their birds and wild birds, and reporting sick birds or unusual bird deaths to State/Federal officials, either through your state veterinarian or through USDA’s toll-free number at 1-866-536-7593. Additional information on biosecurity for backyard flocks can be found at

USDA emphasizes that poultry, poultry products and wild birds (see biosecurity and wild birds) are safe to eat if they are properly handled and cooked to a temperature of 165 degrees Fahrenheit.

Background Information
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.
USDA has identified two mixed-origin viruses in the Pacific Flyway: the H5N2 virus and new H5N1 virus. The new H5N1 virus is not the same virus as the H5N1 virus found in Asia that has caused some human illness. The new H5N1 virus is not expected to be a human-health risk, but rather to have the same or a lower risk than H5N8. Detailed analysis of the virus is underway in cooperation with CDC.

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Dossier Taiwan: Poultry cull called inhumane

Taipei Times, Sat, Jan 31, 2015 By Sean Lin, Staff reporter. With the number of birds culled in response to the avian influenza outbreaks exceeding 1.7 million, the Environment and Animal Society Taiwan (EAST) and Democratic Progressive Party (DPP) Legislator Lin Shu-fen (林淑芬) yesterday slammed what they said were inhumane practices adopted by local governments. The Council of Agriculture also came under fire from the society, who said the council had not updated its culling procedure in compliance with international standards and had been negligent in its duty to monitor the exterminations.

At a news conference in Taipei, EAST played video footage shot during culls last weekend at six poultry farms in Yunlin County — the area most severely hit by the outbreak — and demanded that the council assume responsibility for what it called the cruel treatment of the birds, which included dead and living geese bagged together in blood-stained hessian bags and then snatched up by a crane with a metal claw. Living birds could be seen struggling inside the bags, some of which the group said had been left for more than 12 hours as culling personnel waited for the fowl to suffocate. Geese were shown grabbed by the neck — appearing to be in considerable pain — before being put into the bags.

Bureau of Animal and Plant Health Inspection and Quarantine Deputy Director-General Shih Tai-hua (施泰華) had said that carbon dioxide was used to sedate animals before culling, but EAST chief executive Wu Hung (朱增宏) disputed that, saying that his group’s findings showed that culling undertaken at most farms was carried out without the gas, in violation of extermination guidelines stipulated by the World Organization for Animal Health, of which Taiwan is a member. Wu also rejected Shih’s assertion that soldiers had been deployed to disinfect vehicles along roads used by culling personnel to transport dead birds to incinerators or rendering plants — a disease control measure the bureau pledged to implement last week. Meanwhile, the group’s investigation into extermination efforts by nine local governments highlighted the lack of a standard operating procedure in the extermination methods adopted by local governments.

Yunlin County said that its personnel froze geese with dry ice and Changhua County said exterminators suffocated waterfowl showing weak vital signs with hessian sacks. Pingtung and Chiayi counties, as well as Greater Tainan, used chloral hydrate to cull birds — a practice that has been banned by the US Department of Agriculture because the compound is a weak sedative. None of the local governments that used carbon dioxide were able to provide information on the concentration or quantities used, the probe showed.

Citing World Organization for Animal Health extermination guidelines, Wu said that carbon dioxide — at 40 percent to 70 percent concentration — should be introduced gradually directly into poultry houses to sedate or kill the birds in a manner that causes minimum distress. Alternatively, fowl can be placed into plastic or metal containers into which carbon dioxide is introduced to ensure that fowl are properly anesthetized prior to extermination, Wu said, adding that placing birds into hessian sacks did not meet this requirement.

Lin questioned the council’s inactivity over improving culling methods despite the millions of New Taiwan dollars in grants it has distrubuted to academics to conduct research into the field, the results of which include an article describing an automated carbon dioxide administering bagging machine, written by National Chiayi University professor Huang Ching-hsiang (黃慶祥), and an article published in 2008 on an alkaline foam-spraying system for chicken euthanization by National Chung Hsing University professor Yang Chi (楊繼). However, Shih said chloral hydrate was used to sedate the birds and the practice should therefore be considered humane. He said that the bureau would address its administrative negligence and improve its extermination measures.

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Dossier H5N8: 65 Taiwan Farms With Suspect Fujian H5N8 & H5N2

Taiwan is facing the dramatic spread of H5N2 and H5N8. The number of suspect farms has increased from 38 to 65 and the number of confirmed farms has increased from 9 to 20 in one day. These increases support media reports stating that initial cases may have been noted as early as October, but was being unsuccessfully managed in farms which failed to report unusual deaths or dramatic drops in egg production.

(Translated from the publication in NowNews, Taiwan) Domestic bird flu siren, waterfowl industry is facing the most serious outbreak of bird flu over the years, anti-seizure Bureau today (January 13 2015) announced the latest test results, Yunlin and Chiayi diagnosed then add 11 games goose games, Taiwan estimated to cause 270,000 goose loss; in addition, the submission of new cases and 27 field sampling Bulletin, Taoyuan and Kaohsiung City also received a suspected outbreak, Tainan add a chicken farm, a total of 65 games in Taiwan seven counties abnormal mortality epidemic outbreak.

According to the Bureau of Statistics to anti-seizure ended today 11:00, 11 new confirmed again today goose games, including seven new Yunlin County, Chiayi County, two games, two games in Pingtung County; COA confirmed that this wave of bird flu Waterfowl the first time the most serious outbreak, Taiwan has had 20 confirmed cases of the field is expected to affect 270,000 geese production.

COA noted diagnosed games in 14 games for the new H5N2 subtype avian influenza, six games for the H5N8 subtype of avian influenza; Cai Xiangrong, director of animal health instructions, H5N2 is the country’s second case of a pandemic virus infected waterfowl ducks and geese, is The most serious outbreak first waterfowl, the present value of the peak of the epidemic, the diagnosis field more for the high incidence of goose farm suspected of geese spread of infection.

COA chairman Chen Bao-ji also appeared today in the press conference after the animal epidemic prevention group meeting, Chen Bao-ji said two years ago that have informed the H5N8 outbreak began around through e-mail, conference materials in both statistical frequency; the face of an outbreak, vaccination will be the highest specifications measures with increased culling, please contact the EPA and does not rule out additional military assistance disinfection and treatment of animal carcasses, the first time control, “Let the virus disappeared from Taiwan,” the future of open farms and strengthen protection of migratory birds.

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AVT session 1: The Principles of Outbreak Response

This is the first of a series of 6 presentations on the subject of Emergency Response to an outbreak of Avian Influenza.

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AVT session 2: Depopulation Strategies

This second presentation of a series of 6 AVT presentation on Emergency Response to outbreaks of Avian Influenza focuses on depopulation strategies, rapid response management, culling, storage, transportation, composting and disposal of carcasses.

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AVT session 4: Cleaning, Disinfection & Biosecurity

This fourth presentation of a series of 6 AVT presentations on Cleaning, Disinfection & Biosecurity risks related to outbreaks of Avian Influenza.

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