The 3 P’s of Avian Influenza: Prevent, Plan, Practice 1

Is There a Monster in the (Poultry) House? 2

AI Outbreak in Europe in 2003: Lessons to Be Learned 4

Depopulation of Poultry Flocks during Disease Outbreaks and Other Catastrophic Events 9

Disposal Options for Avian Influenza Flocks 10

Spring 2006 Volume 7, Number 1

Editor’s Note

The 3 P’s of Avian Influenza: Prevent, Plan, PracticeThese days everyone from the poultry industry wonders what may be heading our way as birds start their migratory flight north to their breeding grounds. Will this time bring the undesired virus? We cannot stop wild birds from flying and carrying viruses with them, including AI. However, there are a few things we can do that can be summarized as the 3 P’s of Avian Influenza: Prevent, Plan, and Practice. Prevent any contact of wild birds with poultry and apply very strict biosecurity measures to reduce the chances of an outbreak. Do not wait until an outbreak occurs; establish a clear plan of action beforehand when

See 3 P’s on page 2

is published by the College of Agriculture and Natural Resources, University of Maryland, College Park, Maryland.

EDITORSInma Estevez, Ph.D.Roselina Angel, Ph.D.Dept. of Animal and Avian SciencesUniversity of MarylandCollege Park, MD 20742

HOW TO CONTACT USInma Estevez, Ph.D.E-mail: iestevez@umd.eduTel: 301-405-5779Fax: 301-314-9059

Roselina Angel, Ph.D.E-mail: rangel@umd.eduTel: 301-405-8494Fax: 301-314-9059

CONTRIBUTORS

Daniel R. Perez, PhD. Assistant ProfessorDepartment of Veterinary MedicineUniversity of Maryland, College Parkdperez@umd.edu

Harm KiezebrinkIndependent Expert in the Control of Avian Influenza at the Farm LevelAdcare GmbH (Munich, Germany),center@ad-care.com

Dr. Nathaniel L. TablanteExtension Poultry VeterinarianUniversity of Maryland, College Parknlt@umd.edu

Bud MaloneExtension Poultry SpecialistUniversity of Delawaremalone@udel.edu

In This Issue

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you have time to think and design the best strategies for effective con-trol. And practice! Make sure you have the opportunity to do a mock trial to determine the effectiveness of your plan of control. This issue of Poultry Perspectives offers informa-tion that can be used to comply with the 3 P’s.

There is never going to be a better time to work on a plan than RIGHT NOW!

3 P’s from page 1

For the past year or so, the media has flooded newspapers, radio and television shows, and the Internet with the fear that a new influenza pandemic is looming over us. Is that fear founded? When will the pan-demic occur? I work with poultry all the time—am I at risk of becoming infected and dying? What can we do to protect our poultry and our-selves from the effects of this virus? I will go over these questions in the context of poultry avian species: there are approaches that are easy to implement and can stop the spread of these viruses that can infect people. I must point out, however, that potentially pandemic strains will continue to emerge from wild-life avian hosts. The best weapon we have to control the emergence of these viruses is to adopt strict bio-security measures, implement good surveillance strategies, and learn more about the risks of the disease for animals and humans.

Avian influenza is a disease of poultry, whose disease symptoms vary from completely mild or unnoticeable to a catastrophic disease with a mortality rate that can reach up to 100 percent in some avian species. The natural hosts of the virus are ducks, shorebirds, and other species of wild aquatic birds. In the natural hosts,

influenza infections cause almost no disease signs and the infection is established mostly in the intestinal tract. The virus is excreted with the feces into the water, promoting a cycle of fecal-oral transmission. Occasionally, the virus “jumps” from wild birds to domestic birds causing disease outbreaks (sometimes briefly subclinical, and then becoming more obvious as the disease increases in virulence).

The surface of the virus contains two major components, which are the targets of antibodies generated by the host’s immune system. These two components are divided into subtypes based on the ability of antibodies to recognize them. There are 16 subtypes of one of the components known as HA or hemagglutinin and 9 subtypes of the other component, known as NA or neuraminidase. Thus, the nomenclature of influenza viruses includes the subtype characteristics of the virus. For example, the H5N1 viruses in Asia contain an HA of

subtype 5 and an NA of subtype 1. Both components are essential for the survival of the virus, and antibodies created against the HA can prevent the virus from infecting the cell.

In addition, influenza viruses are named based on characteristics of the host, the place of isolation, some form of strain identification code, and the last two digits of the year of isolation. For example, A/chicken/Hong Kong/YU562/01 (H5N1) is a type A H5N1 influenza virus (all avian influenza viruses are type A viruses; humans are affected by types A and B), isolated from a chicken in Hong Kong in 2001 and identified as YU562. Because the genome of influenza viruses is made up by segments and co-infections in birds are common, influenza viruses with many different combinations of HA and NA subtypes have been isolated in nature. Only viruses of the H5 and H7 subtypes are known to cause high mortality in birds. All other virus subtypes cause a milder

Is There a Monster in the (Poultry) House?by Daniel R. Perez, PhD.

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form of disease affecting either the intestinal or respiratory tracts, or both.

Signs of disease may include excess mucus, diarrhea, watery eyes, and drops in egg production. The more virulent forms of the disease are accompanied by neurological disorders and massive hemorrhages, which are clearly noticeable as a purple coloration on the combs and feet. The time course of the infection also varies greatly from a few days to a sudden disease that kills the birds in less than a day.

Accumulation of specific mutations on the HA of the H5 and H7 subtypes results in the emergence of strains with high virulence and mortality; however, mortality rates can vary greatly among different avian species, with the most frequently affected being chickens and turkeys. It is not known exactly which avian species contribute to the emergence of these highly pathogenic strains, although both chickens and turkeys seem to play a major role. Many disease outbreaks in chickens and turkeys have started with H5 or H7 subtypes that were very mild, that sometimes went undetected and later became highly virulent.

Because many other intestinal or respiratory diseases of poultry can cause similar disease symptoms, we cannot rely on disease symptoms alone to diagnose avian influenza. Thus, constant monitoring of the flock is encouraged by submitting serum, tracheal and cloacal swabs to the diagnostic laboratory to perform antibody tests and virus isolations. The mild forms of the disease may last only a few days, leaving only a small window of opportunity to detect the virus. Serum samples should also be collected to analyze the presence of antibodies against the virus, which last much longer and are easier to detect.

Several diagnostic companies are developing tests that will allow the detection of the virus or antibodies to it at the farm level. These tests

are easy to use and very sensitive and are currently pending USDA approval. A word of caution must be used here: If the test is positive, it is most likely that avian influenza is present in your flock; however, the test will not indicate what HA or NA subtype it is. A reliable diagnostic laboratory test must be performed to confirm the presence and characteristics of the virus. On the other hand, a negative test at the farm level does not guarantee that the flock is free of avian influenza. Submission of samples to the lab is strongly encouraged, even when the flock appears perfectly healthy. Making a habit of screening for potential disease signs, excess

an Avian influenza virus from wild birds are very low. Infection with some viruses may be very localized and not life-threatening: H7 infections, for example, can cause conjunctivitis (pink eye) in humans. Avian influenza viruses that become adapted to domestic flocks are also not likely to “jump” to humans. However, the experience in Asia has taught us that letting influenza viruses circulate in domestic bird species for extended periods can lead to strains that become more and more efficient at making the “jump” to humans and other animal species. Once again, being vigilant, identifying potential disease signs, and practicing strict biosecurity measures provide greater protection for you and your flock. The Animal and Plant Health and Inspection Services (APHIS) has an excellent online resource called Biosecurity for the Birds (http://www.aphis.usda.gov/vs/birdbiosecurity/), which provides extensive information about biosecurity and other strategies for protecting your flock and yourself. You can also contact APHIS at toll-free 1-866-536-7593. Additional information about avian influenza can be found at http://www.agnr.umd.edu/aicap, which provides information about the disease, contains several educational resources, and presents an overview of several research projects currently funded by the USDA on prevention and control of avian influenza in the U.S. (a newly updated version of this web resource is expected by mid-November).

The current H5N1 situation has sounded the alarm in animal and public health organizations at the international and national levels. The World Health Organization speculates that it will take at least two years before H5N1 viruses are controlled in Asia. The list of countries reporting outbreaks of H5N1 HPAI continues to increase despite the 160 million domestic poultry that have died or been culled in Asia to control the spread of the disease. The estimated

“Because many other intestinal or respiratory

diseases of poultry can cause similar disease symptoms, we cannot rely on

disease symptoms alone to diagnose Avian

Influenza.”

mortality, and taking samples for laboratory analysis will achieve two purposes: Both you and your flock will be protected from spreading a disease that can carry major animal and public health implications. Remember, not reporting the presence of the virus in your flock will most likely backfire on you. Sooner or later, you and your flock will be severely affected.

Am I and those in contact with chickens and their products at risk of becoming infected? Most avian influenza viruses, regardless of the subtype, do not infect humans. Avian influenza viruses from wild birds are so adapted to them that the chances of humans becoming infected with

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economic losses to the Asian poultry sector are approximately $10 billion, threatening the livelihood of millions of people. Recent findings suggested that migratory aquatic birds might facilitate the transmission of the H5N1 viruses, and recent reports indicating the presence of the virus in several countries in Europe have confirmed this assumption. Importation of exotic birds is another way of spreading the disease as the virus has recently been reported in the United Kingdom in imported birds. There has to be a major effort worldwide to strictly control the movement of exotic birds between countries, not only to control the spread of avian influenza, but also other known or unknown diseases. Is the U.S. vulnerable? Imported birds are strictly quarantined and tested before they are allowed to enter the U.S., so in this regard the U.S. is protected. The U.S. does not allow importation of live

commercial birds from Asia and similar measures have been quickly adopted for countries reporting avian influenza. However, the virus could potentially enter the U.S. through migratory birds, smuggling of birds, or through people. Keep your birds in the house and do not let them co-mingle with wild birds. Control the access of other animal pests into the poultry house. Do not let anyone you do not know come close to your poultry house.

Are these fears founded? Absolutely. The fact that the virus has managed to cross to humans several times with significant mortality and that all human influenza pandemics have initiated from an avian influenza virus, put H5N1 viruses in the list of potentially pandemic viruses. When will the H5N1 pandemic occur? We do not know. It may start tomorrow or it may not happen in our lifetime; however, we do need to be prepared because a pandemic influenza

virus can emerge at any time. If the previous 100 years gave us three pandemics, how many are we going to get in the next 100 years? As the world prepares for the inevitable, poultry farmers around the world can be at the forefront in the control of the disease and, thus, prevent the emergence of pandemic influenza strains at the amplification stage: poultry species. In the research arena, novel vaccine strategies and faster and more sensitive diagnostic tools will soon provide a number of alternatives for the poultry sector to combat the disease. In the future, researchers will be able to predict which viruses are more likely to be a pandemic threat. However, it is only going to be through the combined efforts of poultry farmers, poultry veterinarians, government agencies, diagnosticians, and researchers that the inevitable be made preventable.

AI Outbreak in Europe in 2003: Lessons to Be Learnedby Harm Kiezebrink

IntroductionIn October 1997 the poultry world was shocked by the news that avian influenza (AI) had struck Asia for the first time in decades. In Hong Kong all poultry was culled within days and the outbreak seemed to be under control. But as we know now, it did not disappear. The same H5N1 virus is currently rushing with dev-astating force over the globe. Many experts and governments tried to warn about the necessity of control-ling the disease to avoid potential catastrophic consequences without success. It is time to come back to reality and stick to the facts, espe-cially when it comes to preparing the poultry industry for a possible outbreak.

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Consequences for the Industry

Avian influenza is not solely a chicken disease. AI can also affect other bird species as well as humans. Nevertheless, the threat of humans contracting AI has always been shown to be directly linked to poultry and the poultry industry.

This connection can be extremely devastating for the industry, as poultry consumption drops after the appearance of AI. I will give an example that shocked the farming industry in Holland. A Dutch animal welfare activist group who are opposed to the commercial poultry industry misused the link between avian influenza and the pandemic threat to human health in a public campaign against the poultry industry. In December 2005 the Dutch animal welfare activist group, ‘Wakker dier’, began to exploit general public fear about the human implications of AI by broadcasting a totally misleading radio commercial with the slogan “Slow down the virus, don’t eat chicken.” Poultry farmers reacted quickly, asking a judge to stop this campaign immediately, but without any success. In spite of poultry producers’ arguments that AI in Asia and Europe occurred only within wildfowl and backyard farming and that the ‘Wakker dier’ campaign was based upon fragmented information pulled out of context, the judge concluded that ‘Wakker dier’ gave sufficient “facts to justify” their campaign. The judge rejected the arguments and demands from the poultry industry. The disintegrating Dutch farming industry now faced an unexpected drop in poultry products just a few days before Christmas.

How the Truth Became So Distorted

News agencies start their reports with this statement or one similar: “Today it was confirmed that the virus H5N1, the deadly virus that

under certain circumstances can affect humans, has been found in a population of migrating ducks. The export of all poultry products is directly banned.” I have heard these sentences over and over again, especially in the last couple of weeks. The consequences are clear. The public links the outbreak of avian influenza directly to poultry, because of the ban on poultry products. As a consequence, the consumption of poultry has dropped dramatically. In Romania, for example, poultry consumption has been reduced by 60 percent due to media reports. When the public panics the first victim is the poultry industry. In a competitive market, the poultry industry has a lot to

their own birds and they should avoid contact with poultry products coming from poultry that is not slaughtered by the poultry industry.

Avian influenza is closely connected to the poultry industry in the public’s mind because AI can spread via chickens that have come in contact with the virus. This is true not only in free range farming, but also in backyard farming and with fighting cocks. Therefore, it is important to explain to the public that they have to avoid all unnecessary contact with poultry, wild fowl, and domestic birds in order to prevent the virus jumping to humans.

Lessons LearnedThe Dutch poultry industry and

Dutch government learned a very important lesson during the 2003 AI crisis in Europe. As a result, all farms in the Netherlands are inspected for AI once a year; all free range farms are inspected four times per year and during the migration season, all free range poultry have to be kept inside or under a net. The costs for this operation were covered by the farmers themselves. From this crisis, several lessons can be learned and applied to the poultry industry in the U.S.

Lesson One: Be Prepared!

Why did the Dutch farmers accept such a drastic measure and such high costs? Because they had to survive the financial consequences of the first major outbreak in 2003. Unprepared and neglecting their own responsibility, they trusted the government to take care of the crisis. They felt that if a disaster struck, the government would act and they would not have to worry.

Now, after the experience of 2003, the farmers know better. Now they know they have to play an active role in surveillance and biosecurity programs, but that was not the case in 2003. At that time, the farmers only thought in terms of financial compensation

“The consequences are clear. The public links the outbreak of

Avian Influenza directly to poultry, because

of the ban on poultry products.”

lose and the best strategy to control potential negative effects of AI is to be open with the public. It is in the best interests of the poultry industry to launch a campaign to show that the industry does everything it can to prevent an outbreak and also that the industry takes animal welfare issues seriously.

Informing the PublicAs the Dutch example shows, the

industry should take communication about the consequences of avian influenza seriously. They should explain to the public and their customers that it is perfectly safe to eat poultry products as long as the product is coming out of the grocery store. People should not slaughter

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and relied on their assumption that the government would take care of them. After all, there were funds created to cover the direct costs: European Community (EC) funds covered 50% of the direct costs; local government covered 25%; and farmers’ funds (created by the farmers organizations themselves) covered 25%. What the Dutch poultry industry learned from the 2003 crisis is that it is far more important to think in terms of preparedness than in terms of financial cost.

In 2003 the Dutch government prepared for an AI outbreak based on wrong assumptions. The Dutch contingency plan in 2003 for an AI outbreak was not successful because it was based on an obsolete culling method. The contingency plan was still based on the use of HCN, although another European Union (EU) law forbids this type of nerve gas. HCN is listed as a potential weapon of mass destruction. The services in charge ignored this fact and the plan could not be carried out. The fact that Holland was not prepared with a well thought out plan was the main reason for the huge impact of the 2003 crisis. And because of the great number of affected farmers, the funds created by the farmers’ organization dried up the first week of the outbreak!

Take Holland as an Example

I don’t know exactly why, but I am pretty well convinced that unpreparedness is still too common for most industries and governments. False hopes and a reluctant government are the best ingredients for a future financial disaster. Here are some facts and figures from 2003:

• In February 2003 the crisis struck in Barneveld, the heart of the Dutch poultry industry. The R0 factor, the reproduction factor, was 8. That meant that one infected farm was the source of infection at 8 other farms.

• In total, 1,200 farms were cleared and almost 32 million birds were culled.

• Thirty-three percent of all farms in Holland were involved.

• The outbreak was stopped within 10 weeks.

• On a 24/7 basis, more than 3,000 people were involved in fighting the disease, culling animals, and controlling the operations.

• Total direct costs were approximately 376 million Euros; the uninsured indirect costs were 1 billion Euros.

• 84 people were directly infected with the virus and they infected approximately 8,500 other people among their families, friends, and relatives.

There is a pattern that signals things to come and we in Holland started to understand this pattern:

• Migrating birds enter border and mix with stationary birds, most of the time in wetland areas.

• Dead wild birds are found and examined.

• Confirmation of avian influenza.

These are the first signs, signalling that procedures have to be put in place to keep the virus within the wildfowl population and in a restricted area. The following immediate actions have to be taken:

• Completely halt the transport of birds and other animals.

• Control borders in the region.• Ban fishing and hunting to

keep people out of the area as much as possible.

• Rigorously cull all poultry in the infected area, in an area of about 1.5 miles around the source of the outbreak.

• Daily sampling and inspection.

• Reduce the number of people entering the zone, especially the press.

• Vaccinate against human flu all farmers, veterinarians, and poultry industry workers as well as the general population working or living within the zone.

• Keep all domestic livestock in barns.

• Prepare a ring vaccination plan for poultry around the infected zone.

Lesson Three: Protection Starts with Proper Planning

This is the signal for the industry to maximize efforts to protect their farms, their employees, and their families. This means that each farm should work on an individual contingency plan on a

“In 2003 the Dutch government prepared for an AI outbreak based on

wrong assumptions.”

• Unfortunately, 1 veterinarian died.

• After one year, 25% of the entire industry had not survived.

As a note, Holland had to deal with the lesser pathogen, H7N7 virus. If this had been the H5N1 version, the consequences would have been much worse.

Lesson Two: Adequate Response

Looking at the facts above, it seems that scientists are largely concerned that governments as well as the poultry industry are not prepared for a crisis of this magnitude.

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farm level, on a regional level, and on a countrywide level. This will help to keep a possible outbreak within the industry as localized as possible. The jump of the virus itself into the industry can hardly be prevented but, with a little luck, these efforts will help to minimize the consequences. Someone wisely compared preparedness with ‘having oil in your lamp when you know darkness is coming.’

Lesson Four: Safety Before Animal Welfare

One thing I have learned from my experience in the field is that safety of the operators has to be maximized. New techniques are needed to minimize the number of operators needed and to guarantee that animals are culled in the most humane manner. This is a tough job and not very rewarding, but is absolutely vital to prevent a pandemic through the operators. It is quite simple. Technically speaking, culling animals can never be done in an animal welfare friendly way. In spite of all efforts to choose the best possible culling option, the technique is only a small part of the operation. It is largely in the hands of those who carry it out and control the culling operation. These people include cullers, veterinarians, and governmental officials in the field who carry out the responsibility for the operations. It is never the scientists, animal welfare people, or politicians who risk their lives by going in the infected areas. Animal welfare is a very important responsibility, but stopping the spread of the disease must always be the highest priority. By stopping the spread of the disease, the lives of millions of animals can be saved. However, in the aftermath of a crisis, those who were responsible for the culling operations are always the first to be blamed for the killing of innocent animals.

Lesson Five: Manage the Chain

When it comes to responsibility to prevent an outbreak, a ‘hobby farmer’ with a stock of five birds in his backyard is just as responsible as a broiler farmer with a stock of 1 million birds. The difference lies in the details, but everything possible has to be done to prevent the spread of the virus.

Lesson Six: The Method of Choice

The most appropriate culling method for the backyard farmer may be totally different from that of the commercial farmer. But for all categories of farming, dedicated methods have to be in place before a possible outbreak. The best methods are:

• Gas bags. An improvement on this method is the use of bags made out of biodegradable plastic that are

put into dustbins. The bags are first filled with at least 60% carbon dioxide before being filled with animals. The pre-filling renders the animals unconscious before they die, so they do not suffer. The animals are stunned within 30 seconds and die within one minute. The bags, together with some manure, are then landfilled above groundwater level. After one year, the bag is gone, together with the birds and the virus. This flexible and effective low cost method is the preferred way to cull small flocks (up to 1,000 birds).

• Container systems. There are three types of containers in use in Holland: small 340 litre bins, 1.100 litre wheelie bins, and 20 foot container. The most widely used size is

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the 1,100 litre container. All systems work on the same principle: first the containers are filled up with a minimum of 60% carbon dioxide before the animals are put in. As with the gas bags, the birds are culled within 30 seconds and killed within one minute. This method is mostly used for layer hens in cages, because the animals have to be taken out of their cages anyway.

• Electrocution. The fourth method is the use of a mobile electrocution line, similar to what is used in slaughterhouses, but with a much higher electric current. The birds are killed within a fraction of a second and therefore this is the preferred method from an animal welfare point of view. A negative aspect of this method is that the animals have to hang upside down before they are killed. This technique can generally be used for all types of animals including broilers, layer hens, turkeys, geese, and ducks. This technique is often used if the fifth method, stable gassing, failed.

• House gassing. Carbon dioxide gas is pumped under pressure into a house with broilers, parent stock, and young turkeys. This method only works if the stable can be sealed off, keeping sufficient space for the air in the stable to escape at the moment the carbon dioxide is pumped in. It takes 30 minutes to one hour until the birds die. From an animal welfare point of view, it is better to choose a method that leads to a quicker death, but when the quantity of birds per house is large, there are not many alternatives. This is the method of choice in Europe for culling large quantities of birds, especially broilers. It

is important to keep in mind that in Holland, the house gas method could only be practiced when the house was suitable for this method, as was the case in 33% of Dutch houses. That means that 67% of all the houses in Holland were not suitable candidates for the use of the preferred gassing method, due to the type of housing or to the type of animal (ducks, layer hens, turkeys, very young birds). So even though house gassing was the preferred method, 67% of all the farms had to use a variety of other culling methods.

carcasses were put into air- and watertight containers and transported by truck to the rendering plant. The maximum rendering capacity was 250 tons per day with a limited number of vehicles to transport the dead animals to the rendering plants. Despite the risk that transporting diseased birds could cause further spread of the disease, there were few other options available at that time. Landfill in Holland is nearly impossible, because we live below sea level, so the risk of the virus touching groundwater level was too high and house fermentation had not been developed at that time.

Conclusion: Start Yesterday

It is important to go back to common sense and stay with the facts. There is no reason to panic yet. However, only a few countries have the necessary action plan to control an outbreak in the first 24 hours after it is confirmed. At the moment there are few specialists working in this field worldwide who sell or rent the culling equipment described above.

As a specialist with experience in this field, I am convinced that we will be able to manage a large scale outbreak within the poultry industry. There is one condition: the industry has to take this very seriously and needs to take the responsibility and act—starting yesterday.

Harm Kiezebrink is an independent consultant who works for the poultry industry, governments, and veterinary services worldwide. In addition to the crises in Holland and Belgium, Harm was involved in control outbreak planning in other European countries such as Spain, Portugal, France, England and Germany, as well as in Asia (China, Thailand and Vietnam). Harm is currently active in Romania advising the minister of agriculture and representatives of the Romanian poultry industry.

• Carbon monoxide. Don’t use carbon monoxide. In addition to availability problems, carbon monoxide is highly flammable, and caused a fire on at least one farm during the Dutch outbreak.

In practice, a variety of different methods must be in place before an outbreak occurs.

Lesson Seven: Beware of Unexpected Limitations

Whatever method is chosen, success in culling always comes down to the entire operation, rather than the technique. The make or break factor in Holland was disposal of the dead birds. In Holland, the method of choice was rendering the animals. The rendering capacity dictated the speed of operation. The

“It is important to go back to common sense and stay with the facts. There is no reason to

panic yet.”

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Depopulation of Poultry Flocks during Disease Outbreaks and Other Catastrophic Eventsby Dr. Nathaniel L. Tablante

Depopulation of poultry flocks is necessary during infectious disease outbreaks and natural disasters. In the case of avian influenza, which has gained notoriety in recent years because of the potential risk to human health, destruction of infect-ed flocks is required in order to prevent further spread of the disease. The destruction of these flocks must be done as quickly as possible, using proper and humane methods of mass euthanasia.

The word euthanasia is derived from two Greek words that mean “good death.” The term essentially refers to a humane death that occurs with a minimum of fear, pain, and distress. In 2000, the American Veterinary Medical Association (AVMA) developed specific guidelines on the euthanasia of animals. The 2000 Report of the AVMA Panel on Euthanasia states that “under unusual conditions like disease outbreaks and natural disasters that require depopulation, the most appropriate technique that minimizes human and animal health concerns must be used.” According to these guidelines, the method of euthanasia must result in rapid loss of consciousness, cardiac or respiratory arrest, and ultimate loss of brain function.

Choosing the method of euthanasia depends on several factors such as human safety, skill of the operator, aesthetics, cost, other limitations, and consideration of the humaneness of the method. Currently, only two methods of mass euthanasia of poultry are considered acceptable by the AVMA. These are 1) cervical dislocation, and 2) use of inhalant gases such as carbon dioxide (CO2). In a disease outbreak where prompt response is critical, cervical dislocation is impractical, labor intensive, and time consuming

as it involves individual handling of thousands of birds. Therefore, inhalant gases like CO2 are widely used to euthanize large numbers of birds at a time. Carbon dioxide for mass euthanasia of poultry, although not perfect, is widely used because it is inexpensive, readily available, and poses minimal risk to humans. To be effective, a concentration of 60 to 70 percent must be achieved. Broiler chickens and turkeys are sensitive to CO2 but waterfowl are more resistant and require higher concentrations and longer exposure time.

For meat-type poultry, the following methods of CO2 euthanasia have been developed and used in actual AI outbreaks:

1. Whole house method.• Used mainly in breeder

houses.• Involves the use of a CO2

tanker truck.2. Partial house method.

• Used also in breeder houses.

• Involves driving birds into one end of the house in the litter area and sealing the area off with a sheet of poly.

• Utilizes CO2 tanker trucks or 50 lb. cylinders.

3. Portable panels with tarp.• Works best with turkeys.• Involves the use of ply-

wood panels that are set up against posts.

• Birds are driven into the enclosure formed by the panels.

• CO2 cylinders are placed on the floor and a sheet of poly is placed on top of the birds using the top edge of the panels for support.

4. Livehaul euthanasia cabinet. • Ideal for broilers.• Utilizes regular livehaul

crates. • Fabricated steel cabinet is

placed on top of crate con-

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taining the birds.• CO2 is pumped into the

cabinet.5. Poly euthanasia tent.

• Ideal for broilers in clear span houses.

• Birds are driven to one end of the house one group at a time.

• CO2 cylinders are placed on the floor and poly is placed on top of birds in two opposite and overlap-ping layers.

• Works well with in-house composting of carcasses.

These methods were developed and later refined by poultry industry personnel during actual outbreaks of avian influenza. Those involved in depopulation of poultry flocks know fully well that mass euthanasia of poultry is not a pleasant task. It is physically and emotionally stressful for all personnel involved in the process and distressful for poultry as well if the euthanasia is done improperly. However, in the event of a catastrophic disease such as avian influenza, it is a necessary evil. In order to expedite the process, protect the welfare of poultry, and ease the physical and emotional burden on humans, the following criteria must be met:

1. All personnel involved in depopulation of poultry flocks must undergo intensive training on emergency preparedness, poultry welfare, and methods of euthanasia, and must follow the Centers for Disease Control guidelines for poultry workers involved in avian influenza control. (See http://www.cdc.gov/flu/avian/professional/protect-guid.htm for details.)

2. The poultry industry, along with state and federal agency representatives must prepare in advance for an emergency poultry disease outbreak by having an action plan in place, including provisions for necessary personnel, supplies, and equipment.

3. The different methods of CO2 euthanasia must only be performed under the direct supervision of a veterinarian or trained professional. This professional must insure that the birds are treated in a humane manner from start to finish. Acts of animal cruelty like the use of baseball bats and woodchippers are absolutely forbidden and those who commit such inhumane acts will be

prosecuted accordingly.4. A safety officer to monitor

compliance with OSHA guidelines and ensure safe levels of CO2 for humans must always be present during the euthanasia procedure.

Practicing the different methods of mass euthanasia and carcass disposal through simulated exercises is strongly recommended. Not having the necessary skills and resources when an outbreak occurs can result in the loss of valuable time to control the outbreak, which may result in a major economic disaster and bad publicity. Extension specialists and poultry professionals must play a key role in educating poultry workers, farmers, and all those involved in disease control and eradication efforts on proper methods of euthanasia and carcass disposal.

References:American Veterinary Medical Association, 2000

Report of the AVMA Panel on Euthanasia, J Am Vet Med Assoc 2001, 218:669-696.

UC Davis, Center for Animal Welfare, Euthanasia of Poultry: Considerations for Producers, Transporters, and Veterinarians (undated).

Disposal Options for Avian Influenza Flocksby Bud Malone

Are you prepared to deal with catastrophic mortality disposal due to Avian Influenza (AI) on your farms? Do you have disposal pro-cedures, materials, knowledge and approvals in hand that allow you to respond to this kind of event in a swift, biosecure, economical, envi-ronmentally and socially acceptable manner? There have been several recent examples in which there was uncertainty and lack of knowledge on methods of mass disposal, lack

of preparation to deal with this type of catastrophic event, and perhaps more important, not having proce-dures pre-approved by local and state regulatory authorities. The consequence of these situations has been conflict, delays in responding to the emergency at the most critical time period, and added overall cost to deal with the disease crisis.

The following are some of the questions that need to be asked when analyzing potential disposal

options for a disease outbreak. What local, state, and/or federal regulations apply to this situation? What are the viable disposal options given the situation on each farm and house on that farm? Is the house clear-span or pole? How many and what size of birds are involved? What resources, equipment and disposal options are available on the farm, from the poultry company or agency(s) overseeing this matter? Is the AI a low or high pathogenic

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form? With the recent media and human health attention given to “bird flu” (H5N1) in Asia and now Europe, additional safeguards are needed to insure public health. And let’s not forget, how will the public perceive the disposal option being recommended?

The following are some brief highlights of disposal options for AI infected flocks used in the U.S. Local, state and federal guidelines will dictate which options are appropriate given the nature of the AI event.

Burial. At one time, on-farm burial was the predominant disposal option for many types of catastrophic losses. This practice is one of the simplest and most cost-effective ways to deal with mass mortality losses. Trenches with carcasses placed 2-3 feet above the seasonal high water table, placed at a maximum of 4 feet thick and covered with 2 feet of fill on top of the birds has been used for various types of mass mortality losses. Although some states have previously relaxed environmental standards for burial when dealing with an emergency, this situation is changing due to increasing water quality and public perception concerns. In many Delmarva locations having high seasonal water tables, finding a suitable location can be a major challenge. In a disease emergency, trench burial above the water table may be needed but not the preferred method of disposal of AI-infected flocks.

Sanitary Landfill. The use of sanitary landfills has been used for mass disposal of AI flocks in the last few decades. Since all landfills do not accept carcasses, pre-approval is required and there can be logistical challenges when coordinating the transportation and deposition of large volumes of carcasses to these sites. Costs associated with transportation and tipping fees can be significant. During several recent AI outbreaks, there were indications that disposal

options that removed infected carcasses from farms posed a potential risk of spreading the virus to other farms.

Incineration. Portable incineration units (i.e., Air Curtain™) have been used on a limited scale in recent AI outbreaks. Although the end product is very biosecure, there are some logistical and environmental issues with this procedure. The units need to be transported to the region of the country having the catastrophic losses. Carcasses are then transported to a central and preferably remote receiving site. The incineration process is somewhat slow, loading decomposed carcasses poses a problem and it will require disposal of 0.3 tons of ash per ton of carcass. Without the proper fuel source and supervision of the process, smoke and odor can create nuisance complaints. Based on Virginia’s experience with incineration during their 2002 outbreak, this disposal option will likely be a low priority for any future AI events.

Composting. There has been increasing acceptance of composting as a practical, economical and environmentally sound method for disposal of many

types of catastrophic mortality events. Following a major heat loss on the Delmarva Peninsula in 1995, the local universities conducted a demonstration and developed guidelines (Carr et al., 1996) for outside windrow composting of catastrophic heat-loss mortality events. In 2003 another demonstration was conducted on Delmarva to evaluate and demonstrate the windrow composting procedure inside poultry houses. A year later on Delmarva, this procedure was implemented as a means to contain and inactivate the H7N2 AI virus in the carcasses and litter on the three infected farms (Malone et al., 2004). The procedure used on these farms involved the formation of a single windrow 10 to 12 feet wide by 3 to 5 feet high down the center of the house. The litter and carcasses were mixed uniformly and capped with litter or sawdust to cover exposed carcasses. This procedure requires 0.8 inches of litter/carbon per pound of carcass per square foot floor space (Tablante and Malone, 2005). Crushing or shredding carcasses prior to windrowing reduces the additional carbon requirement to compost large carcasses such as roasters and turkeys (Bendfeldt et al., 2005).

After ~2 weeks the windrows can be turned in the house, capped to cover any exposed tissue, and allowed to compost for another 10 days prior to removal. An alternative procedure is to remove the compost after the first 2 weeks and place it in a covered windrow outside the house. Temperatures in the compost exceed 130º F, enough to inactive the virus within a short period of time.

An Ag-Bag composting system has been employed on a limited scale during several recent AI events in the U.S. and Canada. This system requires specialized equipment to mix carcasses with the carbon source, load the mixture into the bags and maintain proper aeration. Due to logistical considerations, it may be more appropriate to transport the carcasses to a central site for composting with this system. Since broiler breeder and caged

layer farms may have limited on-farm carbon sources and these types of carcasses tend to be more difficult to compost, transporting these mortalities to a centralized and professionally operated Ag-Bag site may be appropriate.

In summary, when the decision is made to depopulate a farm for disease control purposes, selection of the disposal method should focus on minimizing disease spread. Several recent AI events suggest every effort should be made to inactivate AI virus prior to carcass (and litter) removal from the house. There is growing consensus that in-house composting is the most biosecure disposal method for a flock with a highly infectious disease like avian influenza.

ReferencesBendfeldt, E., R. Peer, G. Flory, G. Evanylo, L.

Carr and G. Malone. 2005. Can Catastrophic Turkey Mortalities be Composted In-House as a Means of Disposal? Symposium on Composting Mortalities and Slaughterhouse Residuals. Portland, MA.

Carr, L., H. Brodie, J. Martin, Jr., G. Malone, D. Palmer and N. Zimmermann. 1996. “Composting Catastrophic Event Poultry Mortalities.” University of Maryland Fact Sheet No. 732.

Malone, G., S. Cloud, R. Alphin, L. Carr and N. Tablante. 2004. Delmarva in-house carcass composting experiences. Proceedings 39th National Meeting on Poultry Health and Processing. Ocean City, MD. pp. 27-29.

Tablante, N. and G. Malone. 2005. Guidelines for In-House Composting of Poultry Mortalities Due to Catastrophic Disease. Compact disk available from Universities of Maryland and Delaware.

MARYLAND COOPERATIVE EXTENSIONU.S. Department of Agriculture

University of Maryland, College ParkCollege Park, Maryland 20742

Issued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, University of Maryland, College Park, and local governments. Cheng-i Wei, Director of Maryland Cooperative Extension, University of Maryland.

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