Animal Welfare & Disease Control Seminar Sept 23, 2015: Introduction of Avian Influenza into the industry

During the FLI Animal Welfare and Disease Control Seminar, organized at September 23, 2015 in Celle, Germany, a group of experts will give their vision on how the possible contribution of each transmission route could be determined and how a revolutionary new response strategy could be developed, based on the principle of neutralizing transmission routes.

There are several factors, which contribute to the unique presentation of an avian influenza outbreak, like the relationship of this virus with wild waterfowl. The virus is highly pathogenic for chickens and turkeys but not pathogenic for waterfowl.
Since the virus in our current outbreak is not pathogenic for waterfowl, the vast flocks of healthy virus-infected migratory geese and ducks travel thousands of miles, entering into commercial poultry-producing regions while shedding tremendous quantities of infectious avian influenza virus in their feces.
You are more than welcome to participate in this English-spoken event. You can sign up by replying your name, including the name of your institute/company, to angelika.gaupp@fli.bund.de, or by fax: +49/5141-3846-117.

We wanted this seminar to be accessible for all, and for that reason, the participation fee is € 70 only. Unfortunately, the number of participants is limited, so in case you’re interested, please let us know and respond before August 31, 2015. After you signed up, you will receive your detailed payment instructions.

This international – English-language based – seminar is open for animal welfare specialists, veterinary specialists, and emergency response experts. The event takes place on the premises of FLI; starts at 9 AM; and closes at 4 PM, after the general discussion.

In case you need more information or any assistance, please contact me on: 0046 761 731 779 or by mail on harm.kie@gmail.com.

You are very welcome to pass this invitation to all of your colleagues, who may also be interested in the seminar.

I am looking forward to see you there.

Kind regards,
Harm Kiezebrink

Associate Research Fellow FLI

Federal Research Institute for Animal Health
Friedrich Loeffler Institute
Dörnbergstr. 25/27 | 29223 Celle
Tel: +49 5141 3846 130 | Fax: +49 5141 3846 117
http://www.fli.bund.de/

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Dossier AI: Clean-up costs for avian influenza outbreak estimated to top £10 per bird


Clean-up costs could run to as much as £10 per bird for egg producers whose layer units are hit by avian influenza.

 

An outbreak of bird flu at Staveleys Eggs near Preston in Lancashire has, once again, highlighted the devastation the disease can cause. Nearly 200,000 laying birds have been culled following confirmation of avian influenza, and strict restrictions have been put in place around the farm and the surrounding area in an attempt to prevent the virus spreading to other nearby poultry units.

The Staveleys are likely to face a huge bill to get this farm up and running again following the outbreak, although no official figures appear to exist to illustrate the likely cost of a post-bird flu clean-up operation on an egg production unit. The Ranger has spoken to a number of people with some knowledge of the clean-up process and the regulatory system in an attempt to gauge the likely financial impact of cleaning an infected site.

“Even on the smallest site, I would be very surprised if you got away with £100,000,” said Julian Sparrey of Livetec Systems. Livetec has a culling standby contract with the broiler industry that allows it to maintain equipment and technology to be used in the event of a notifiable disease outbreak. It was also involved in dealing with the AI outbreak in Hampshire in February this year. It managed the culling and clean up operation for Mackenzie Brothers, whose broiler breeder unit at Upham, near Winchester suffered an outbreak of a low path strain of the virus. Some 10,000 birds were culled.

The scale of the operation at Staveleys is much bigger. A total of 170,000 birds -120,000 cage and 50,000 free range – have been culled and the virus involved is a high path version. The cost of the clean-up at Preston is expected to be far higher than the bill for the clean-up in Hampshire. Julian Sparrey could not reveal the cost involved in the Upham outbreak, but on the infection near Preston he said, “I wouldn’t like to think what the cost will be there.”

Whilst the Government takes responsibility for the preliminary cleansing and disinfection of an affected site, the bill for the secondary cleansing and disinfection is borne by the farmer. The work involves not only cleaning out the sheds, but also the secure removal of the waste water from cleaning the sheds and the cost of dealing with the chicken litter.

A recent outbreak of bird flu involving a high path strain of the virus occurred in Yorkshire in November. A total of 6,000 birds were culled on a duck breeding unit at Nafferton, Driffield. The Ranger understands from other sources that the cost of the clean-up operation at Nafferton amounted to about £10 per bird.

Julian Sparrey agreed with our estimate that £10 per bird could well be a reasonable average to put on clean-up costs, although he said that the bill would vary depending on the circumstances at each individual farm. “It is very difficult to give a price per head because each farm will de different,” said Julian.

Cleaning out the sheds after avian influenza is, in itself, far more costly than a normal clean down. Steve Birchall told the Ranger that the cost of a single clean would be nearly 50 per cent more than usual because of the nature of the cleaning required and because of the restrictions placed on the workforce. “We have to be far more meticulous and the workers who are involved are not allowed to go to any other site for four or five days afterwards. That time has to be paid,” said Steve. For the secondary cleansing and disinfection the cleaning process has to be carried out twice, according to rules laid down by the Department for Environment, Food and Rural Affairs (Defra). Additional cleans may be required if APHA is not satisfied with the result.

The cleaning process can also be far more difficult in cage units – particularly in older buildings. The Ranger understands that some of the heaviest costs facing the Staveleys are for the cage units on the farm. There have been reports that the Staveleys may even be considering pulling some sheds down.

In addition to the bill for cleaning the sheds, there are other significant costs for any producer looking to recover from an outbreak. One of them is the cost of removing waste water. The waste water can only go to a site with the necessary environmental approvals. Julian Sparrey said that providing the necessary facilities to handle the water on site could cost £30,000 and finding a suitable treatment works to take the water nearby could also be a problem. “It is not always easy,” he said. “We were involved in one case where the nearest approved treatment works prepared to take the water was 400 miles away. There were a lot of tanker trips involved,” he said.

Once avian influenza has been confirmed on a farm, all movements to and from the site, as well as the clean-up operation, itself, are tightly controlled by the Animal and Plant Health Agency (APHA). At Staveleys, the culling of the birds began on July 11 and was completed on July 14. Subsequent working restrictions are placed upon any catchers who have been involved in operations in the infected sheds. Like the cleaners, they are not allowed on another site for four or five days afterwards. There are reports of some worried producers telling catchers to stay away from their farms for up to three weeks after working on an infected site.Preliminary cleansing and disinfection at Staveleys was completed on the evening of July 16. It is the secondary cleansing and disinfection that are the responsibility of the farmer.

However, although the farmer is responsible, everything has to be agreed by animal health teams. Julian Sparrey says that the procedures are very stringent. “An approved process for the cleaning has to be agreed with animal health,” he said. “The procedure that is to be used is agreed and written down. Once that is done it becomes a legal document and if you divert from that at all you could be fined £6,000 and face a month in jail. That is how strict it is.”

He said that any piece of equipment entering or leaving the infected site would have to be licensed. Julian said that if he was to be managing an on-farm operation he would probably have portable buildings on the site for workers involved in the clean-up. Facilities would include showers so that the workers could clean themselves down at the end of the day and avoid carrying any infection off the affected farm.

He said that, during a bird flu outbreak, animal health would be on site constantly, checking and overseeing everything that was being done. Everything that needed to be done would require approval and cleaning would be closely monitored. “They will go around wearing white gloves. They will wipe their hands across a surface and if there is the slightest dirt you will be told to do it again,” said Julian. “It is a nightmare for anyone who is unfortunate enough to be affected. Animal Health people are all over you all day.”

The removal of litter was also closely monitored, he said. The muck could be stored on the farm, itself, although it would have to be stacked and covered in a bio-secure way – probably on hard standing so that no infection could leach out into the environment. It would have to be stored for a minimum of 42 days and, if it was stored on site, the farm could not be declared clean whilst it was there. After the 42 days the litter could be disposed of normally, he said.

Another option – one which had been used by some affected farmers – was to find somewhere away from the farm where the muck could be stored for the 42 days. The Ranger understands that the owner of the Yorkshire duck farm hit by AI in November last year made arrangements for the muck to be stored on an airfield.

Another alternative, said Julian, was to send the muck for rendering. This could be done straight away if a suitable plant could be found that was willing to take the litter, although the muck would have to be moved by approved transport to avoid cross-contamination. If this was done, said Julian, only relatively small amounts of litter could be moved at one time. The litter did not render easily on its own and so had to be mixed with other materials. There was also the issue of washing down trucks at the rendering plant to ensure that the virus was not passed on. Compared with stacking the litter, rendering is a more expensive option, although it allows the waste to be moved off farm quickly.

Egg producers will, of course, hope that they never have to deal with the devastating effects of bird flu. Julian Sparrey says that, whilst most people will never be affected, everyone should have plans in place in case the worst should happen. “Know beforehand exactly what you will do if it happens. Is there somewhere you would be able to store the litter away from the farm if you needed to, for example? It is best to be prepared.”

Some producers have made preparations by investing in AI insurance. The Ranger understands that the Staveleys were insured against possible outbreak. However, it would appear that existing insurance policies may well have underestimated the high costs of secondary cleansing and disinfection. Recent outbreaks have shown that the clean-up costs account for a very large part of the bill for an AI outbreak.

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Dossier Transmission: Animal-to-Human transmission of H7H7 in Holland 2003

The outbreak of highly pathogenic avian influenza A virus subtype H7N7 started at the end of February, 2003, in commercial poultry farms in the Netherlands. In this study, published in The Lancet in 2004, it is noted that an unexpectedly high number of transmissions of avian influenza A virus subtype H7N7 to people directly involved in handling infected poultry, providing evidence for person-to-person transmission.

Although the risk of transmission of these viruses to humans was initially thought to be low, an outbreak investigation was launched to assess the extent of transmission of influenza A virus subtype H7N7 from chickens to humans.

Most H7 cases were detected in the cullers. The attack rate (proportion of persons at risk that developed symptoms) of conjunctivitis was highest in veterinarians, and both cullers and veterinarians had the highest estimated attack rate of confirmed A/H7N7
infections.

453 people had health complaints—349 reported conjunctivitis, 90 had influenza-like illness, and 67 had other complaints. We detected A/H7 in conjunctival samples from 78 (26·4%) people with conjunctivitis only, in five (9·4%) with influenza-like illness and conjunctivitis, in two (5·4%) with influenza-like illness only, and in four (6%) who reported other symptoms. Most positive samples had been collected within 5 days of symptom onset.

A/H7 infection was confirmed in three contacts (of 83 tested), one of whom developed influenza-like illness. In three of these exposed contacts an A/H7N7 infection was confirmed. All three were household contacts.The first contact was the 13-year-old daughter of a poultry worker, who developed conjunctivitis approximately 10 days after onset of symptoms in her father.Six people had influenza A/H3N2 infection. After 19 people had been diagnosed with the infection, all workers received mandatory influenza virus vaccination and prophylactic treatment with oseltamivir. More than half (56%) of A/H7 infections reported here arose before the vaccination and treatment programme.

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Dossier H5N1: Spatial, temporal and genetic dynamics of H5N1 in China

The spatial spread of H5N1 avian influenza, significant ongoing mutations, and long-term persistence of the virus in some geographic regions has had an enormous impact on the poultry industry and presents a serious threat to human health.

This study revealed two different transmission modes of H5N1 viruses in China, and indicated a significant role of poultry in virus dissemination. Furthermore, selective pressure posed by vaccination was found in virus evolution in the country.

Phylogenetic analysis, geospatial techniques, and time series models were applied to investigate the spatiotemporal pattern of H5N1 outbreaks in China and the effect of vaccination on virus evolution.

Results showed obvious spatial and temporal clusters of H5N1 outbreaks on different scales, which may have been associated with poultry and wild-bird transmission modes of H5N1 viruses. Lead–lag relationships were found among poultry and wild-bird outbreaks and human cases. Human cases were preceded by poultry outbreaks, and wild-bird outbreaks were led by human cases.

Each clade has gained its own unique spatiotemporal and genetic dominance. Genetic diversity of the H5N1 virus decreased significantly between 1996 and 2011; presumably under strong selective pressure of vaccination. Mean evolutionary rates of H5N1 virus increased after vaccination was adopted in China.

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Dossier H5N1: Different environmental drivers of outbreaks in poultry and wild birds

Different environmental drivers operate on HPAI H5N1 outbreaks in poultry and wild birds in Europe. The probability of HPAI H5N1 outbreaks in poultry increases in areas with a higher human population density and a shorter distance to lakes or wetlands.

This reflects areas where the location of farms or trade areas and habitats for wild birds overlap. In wild birds, HPAI H5N1 outbreaks mostly occurred in areas with increased NDVI and lower elevations, which are typically areas where food and shelter for wild birds are available.

The association with migratory flyways has also been found in the intra-continental spread of the low pathogenic avian influenza virus in North American wild birds. These different environmental drivers suggest that different spread mechanisms operate.

Disease might spread to poultry via both poultry and wild birds, through direct (via other birds) or indirect (e.g. via contaminated environment) infection. Outbreaks in wild birds are mainly caused by transmission via wild birds alone, through sharing foraging areas or shelters. These findings are in contrast with a previous study, which did not find environmental differences between disease outbreaks in poultry and wild birds in Europe.

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Dossier H5N8: Dutch outbreak (2014) linked to sequences of strains from Asia

Genetic analysis of influenza A(H5N8) virus from the Netherlands indicates that the virus probably was spread by migratory wild birds from Asia, possibly through overlapping flyways and common breeding sites in Siberia. In addition to the outbreak in the Netherlands, several other outbreaks of HPAI (H5N8) virus infections were reported in Europe at the end of 2014 after exponentially increasing deaths occurred in chicken and turkey flocks.

Genetic sequences submitted to the EpiFlu database indicated that the viruses from Europe showed a strong similarity to viruses isolated earlier in 2014 in South Korea, China, and Japan. An H5N8 virus isolated from a wigeon in Russia in September 2014 is located in the phylogenetic tree near the node of all sequences for H5N8 viruses from Europe.

In regard to time, this location fits the hypothesized route of H5N8 virus introduction into Europe. Furthermore, for several reasons, it is highly likely that the introduction of HPAI (H5N8) virus into the indoor-layer farm in the Netherlands occurred via indirect contact.

First, despite intensive monitoring, H5N8 viruses have never been detected in commercial poultry or wild birds in the Netherlands.

Second, when the virus was detected, the Netherlands had no direct trade contact with other European countries or Asia that might explain a route of introduction.

Third, because of the severity of disease in galliforms, outbreaks of H5N8 in the Netherlands before November 2014 would have been noticed.

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Dossier AI transmission: Wind-Mediated Spread of Avian Influenza Viruses

Avian influenza virus-infected poultry can release a large amount of virus-contaminated droppings that serve as sources of infection for susceptible birds. Much research so far has focused on virus spread within flocks. However, as fecal material or manure is a major constituent of airborne poultry dust, virus-contaminated particulate matter from infected flocks may be dispersed into the environment.

This study, demonstrates the presence of airborne influenza virus RNA downwind from buildings holding LPAI-infected birds, and the observed correlation between field data on airborne poultry and livestock associated microbial exposure and the OPS-ST model. These findings suggest that geographical estimates of areas at high risk for human and animal exposure to airborne influenza virus can be modeled during an outbreak, although additional field measurements are needed to validate this proposition. In addition, the outdoor detection of influenza virus contaminated airborne dust during outbreaks in poultry suggests that practical measures can assist in the control of future influenza outbreaks.

In general, exposure to airborne influenza virus on commercial poultry farms could be reduced both by minimizing the initial generation of airborne particles and implementing methods for abatement of particles once generated. As an example, emergency mass culling of poultry using a foam blanket over the birds instead of labor-intensive whole-house gassing followed by ventilation reduces both exposure of cullers and dispersion of contaminated dust into the environment, contributing to the control of influenza outbreaks.

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Dossier AI Transmission: Biosecurity and transmission through contact structure between farms

Contacts between people, equipment and vehicles prior and during outbreak situations are critical to determine the possible source of infection of a farm. Hired laborers are known to play a big role in interconnecting farms. Once a farm is infected, culling entire flock is the only option to prevent further spreading with devastating consequences for the industry.

In this paper, based on the HPAI outbreak in Holland 2003, the researchers found that 32 farms hired external labor of which seven accessed other poultry on the same day.

However, they were not the only ‘connectors’ as some (twelve) farmers also reported themselves helping on other poultry farms. Furthermore, 27 farms had family members visiting poultry or poultry-related businesses of which nine entered poultry houses during those visits. The other enhancing factor of farm interconnections was the reported ownership of multiple locations for ten of the interviewed farms and the reported on-premises sale of farm products on one pullet and eight layer farms. Also worth mentioning is the practice of a multiple age system reported on eight of the interviewed farms as this may increase the risk of infecting remaining birds when off-premises poultry movements occur.

AI viruses may be introduced into poultry from reservoirs such as aquatic wild birds but the mechanisms of their subsequent spread are partially unclear. Transmission of the virus through movements of humans (visitors, servicemen and farm personnel), vectors (wild birds, rodents, insects), air- (and dust-) related routes and other fomites (e.g., delivery trucks, visitors’ clothes and farm equipment) have all been hypothesized.

It is therefore hypothesized that the risk of introducing the virus to a farm is determined by the farm’s neighborhood characteristics, contact structure and its biosecurity practices. On the one hand, neighborhood characteristics include factors such as the presence of water bodies (accessed by wild birds), the density of poultry farms (together with the number and type of birds on these farms) and poultry-related businesses and the road network. The use of manure in the farm’s vicinity is also deemed to be risky.

On the other hand, contact structure risk factors include the nature and frequency of farm visits. Therefore, a detailed analysis of the contact structure, including neighborhood risks, and biosecurity practices across different types of poultry farms and poultry-related businesses helps the improvement of intervention strategies, biosecurity protocols and adherence to these, as well as contact tracing protocols. Farmers’ perception of visitor- and neighborhood-associated risks of virus spread is also important due to its relevance to adherence with biosecurity protocols, to contact tracing and to communicating advice to them.

The between-farm virus transmission risks may be split into two categories:

1. Introduction
2. Onward-spread risks

The former entail the target farm’s exposure through incoming contacts (human and fomite), through inputs such as feed and egg trays and through neighborhood-related risks such as air-borne contamination. The latter can be through farm outputs (waste and non-waste), outgoing contacts (human and fomite) and contamination of the neighborhood (e.g., through emissions from the farm). Therefore, all day-to-day farm activities involving people and/or materials and/or equipment going in or out of the farm were systematically analyzed.

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Dossier Transmission: Potential transmission H7N9 between humans (Ro) ranges from 0,06 to 0,35

A new study suggests there have been multiple clusters of human-to-human transmission in recent outbreaks of the bird flu strain H7N9. There were around 400 human cases of H7N9 influenza and 177 deaths in 2013 and 2014, all of them in China. Most patients are believed to have caught the infection from close contact with birds, but the virus’s ability to spread between humans has been uncertain.

In a study published in Emerging Infectious Diseases, scientists from Imperial College London studied data from these outbreaks and used statistical methods to estimate how transmissible the virus is. The results suggest that around 70 cases were caused by an infection spread between people. However, the virus cannot spread easily enough in humans to cause sustained transmission at the level required for a pandemic.

The number of people one infected person will pass on the infection to, on average, is called the basic reproductive number. If the value is less than one, an outbreak would be expected to die out; while a value greater than one suggests an outbreak would grow.
“This study shows that H7N9 is currently short of the critical level of transmissibility required to cause a pandemic”, according to Dr Steven Riley of the MRC Centre for Outbreak Analysis and Modelling.

In the outbreaks studied, the reproductive number ranged from 0.06 to 0.35
. This means that once the virus infects a person, there is only a small risk of that person passing it to someone else. The researchers warned that H7N9 poses a continuing threat, and authorities must be vigilant in case the virus becomes more transmissible. Dr Steven Riley, senior author of the study, from the Medical Research Council Centre for Outbreak Analysis and Modelling at Imperial, said: “This study shows that H7N9 is currently short of the critical level of transmissibility required to cause a pandemic. But even if the reproductive number is less than one, clusters of human transmission can occur. “In Zhejiang, the reproductive number increased between the first wave in 2013 and the second wave in 2014. We have to keep an eye on further outbreaks to see how the virus is evolving.”

The study also looked at the effectiveness of closing live bird markets, which are thought to be the main source of infections for humans. Closing the markets for short periods had little effect on the risk, but longer closures appeared to be more effective.

Dr Adam Kucharski, who worked on the study at Imperial before moving to the London School of Hygiene & Tropical Medicine, said: “Our findings suggest that prompt market closures for a sustained period can substantially reduce the number of infections.” The study was funded by the Wellcome Trust, the Medical Research Council, the National Institute of General Medical Sciences, the EU Seventh Framework Programme, the Fogarty International Center and the Research and Policy for Infectious Disease Dynamics programme.

Reference: Kucharski AJ, Mills HL, Donnelly CA, Riley S. Transmission potential of influenza A(H7N9) virus, China, 2013–2014. Emerg Infect Dis. 2015 May. http://dx.doi.org/10.3201/eid2105.141137

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Dossier AI transmission: After 5 month, transmission routes still unknown

By David Pitt, Associated Press: May 4,2015: Scientist work to answer questions about puzzling bird flu virus. It’s been five months since the H5N2 bird flu virus was discovered in the United States, and producers have lost 21 million birds in the Midwest alone. Yet researchers acknowledge they still know little about a bird flu virus that’s endangered turkey and egg-laying chicken populations that supply much of the nation.

Scientists at the U.S. Department of Agriculture, the Centers for Disease Control and Prevention and other federal agencies are puzzled by the H5N2 virus’s spread — even amid heightened biosecurity measures — and apparent lack of widespread deaths in largely unprotected backyard flocks. “At this point, we don’t know very much about these viruses because they’ve only recently been identified,” Dr. Alicia Fry, the CDC’s leader of the influenza prevention and control team, said. “We’re following the situation very closely because this is something we’re continuing to understand.”

The current H5N2 virus surfaced last winter in Canada and was first identified in the United States in early December, when it was found in a wild bird on the West Coast. This spring, the virus was found in poultry operations in eight Midwest states, forcing commercial producers to kill and compost millions of turkeys and chickens in Iowa, Minnesota and elsewhere.

Scientists speculate that perhaps rodents or small birds, seeking food, tracked the virus into barns. Maybe it’s the work of flies, as the bird flu virus has been found on the insects in a Pennsylvania outbreak in 1983 and in Japan in 2004. The USDA’s chief veterinarian even has floated the idea that wind may be blowing dust and feathers carrying the virus from the barnyard into buildings through air vents. “To me, the main concern is the disease is moving even with heightened biosecurity,” said Richard French, a professor of animal health at Becker College in Worcester, Massachusetts. “Ideally we’ve got to try and figure out the way it’s most likely moving and try to put controls in place to stop that.”

Poultry farms’ biosecurity measures include changing clothes and boots before entering barns, disinfecting equipment and vehicles before they approach barns, and assigning workers to specific barns. As new operations are infected almost daily, USDA epidemiologists also are trying to determine whether the virus came from a wild bird or could have spread from poultry in another barn or a nearby farm.
“We are continuing to evaluate how facilities become positive because we also want to be cognizant of any potential risk of lateral spread from farm to farm,” said Dr. T.J. Myers, the USDA associate deputy administrator of veterinary services. “We are doing those evaluations as we speak, and we really don’t have enough data to report on that yet.”

Another puzzling question has been why there hasn’t been a surge in infections of backyard flocks. The USDA has identified 12 cases including five in Washington in January and February, plus others in Idaho, Kansas, Minnesota, Montana, Oregon and Wisconsin.
Cases might not be reported, French said, noting that commercial operations have a financial incentive to immediately report illnesses because the government pays them for each live bird that must be destroyed. Plus, French said, outdoor chickens could have been exposed over time to low pathogenic versions of bird flu and have developed stronger immunity.

One belief held by researchers will soon be tested: whether the virus will die as temperatures warm and ultraviolet light increases. With temperatures this week in the 70s in many of the affected states and even warmer weather expected soon, infections should decline if that assumption is true.

But David Swayne, director of the Southeast Poultry Research Laboratory in Athens, Georgia, acknowledged it’s hard to predict what will happen. “It’s pretty complex. It involves the climate, the temperature itself, the amount of humidity there,” he said.
Scientists expect the virus to return in the fall along with cooler temperatures and wild birds migrating south, but Swayne says the virus could burn itself out and disappear for a while before that.

Amid all the questions is one about the human element: Could the virus spread to people? So far, it hasn’t, but significant efforts are underway to develop a vaccine just in case. “We’re cautiously optimistic that we will not see any human cases, but there certainly is a possibility that we may,” Fry said.

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