About the Disease and Its Cause
What is avian influenza?
Avian influenza (AI) or "bird flu" is an infectious disease of wild birds (such as ducks, gulls and other shorebirds) and less often of domestic poultry (such as chickens, turkeys, guinea fowl). There is a flu for birds just as there is for humans and, as with people, some forms of the flu are worse than others.
What causes AI?
The disease is caused by type A influenza virus (AIV) which is highly infectious bird to bird, and has many different subtypes.
There are two major types based on the severity of disease that the specific virus can cause in poultry:
- Low pathogenic (LP) types cause mild disease and no or low mortality
- High pathogenic (HP) types cause severe disease and very high mortality
Almost all are LP types, but occasionally HP types emerge. There are over one hundred possible subtypes based on combinations of two surface structures abbreviated with the letters "H" and "N", given the 16 different H types and 9 different N types possible in birds. There are even more classifications based on genetic analyses. These viruses can reassort and mutate into different virus subtypes in unpredictable ways when they circulate over time in different bird populations. For example, a few H5 and H7 LP viruses have the potential to become HP in the right set of circumstances.
Where can the AI viruses be found?
There are 2 main reservoirs of these viruses.
The natural reservoir is wild waterfowl and shorebirds that migrate and commingle freely. It is expected that these birds often harbor and shed viruses into their aquatic (lakes, ponds, marshes, rivers) and adjacent land habitats as part of their natural cycle. The viruses do not typically cause significant disease in the waterfowl, so it is usually not possible to tell if they are infected.
The man-made reservoir is the urban live bird marketing system, that includes suppliers of live poultry and the city retail markets themselves. The markets keep an inventory of live chickens, ducks, guinea fowl and other birds for purchase by certain ethnic and cultural groups for food. The birds are typically custom- slaughtered at the market for the customer. In our region, there are many of these markets in New York City and northern New Jersey, and a few in Philadelphia.
In the case of an AI outbreak in poultry, an additional reservoir of virus is the infected flock or flocks, and the immediate area of the infected farm premises. This reservoir should be short-lived, for as long as it takes to control the outbreak. Blocking or limiting exposure of poultry to these reservoirs are the keys to preventing AI infections in poultry flocks.
How does the avian influenza virus spread in birds?
The virus is shed from infected birds through feces and through secretions from the nose, mouth and eyes. Avian influenza virus can be spread by direct contact between infected birds and non-infected birds, from water sources (streams, ponds, and lakes) contaminated with virus-laden feces, and through indirect contact via contaminated shoes, clothing, equipment and other materials.
Wild waterfowl and shorebirds can introduce the virus into domestic flocks raised on range or in open flight pens through fecal contamination. Transfer of virus between birds housed together also can occur via airborne secretions. The spread of avian influenza between poultry premises most often follows the movement of contaminated people and equipment. However, it is possible for AI viruses to be carried on dust particles suspended in the air, thereby moving for short distances in the wind.
What are the signs of illness of poultry infected with avian influenza?
Low pathogenic avian influenza signs are typically mild. Infected birds can show signs of decreased feed consumption, respiratory signs (coughing and sneezing) and decreased egg production. There may be slightly increased mortality. Birds that are infected with highly pathogenic avian influenza are severely ill, and sudden deaths can be the first and only signs noticed.
Birds can also exhibit one or more of the following clinical signs:
- lack of energy and appetite
- decreased egg production
- soft - shelled or misshapen eggs
- swelling of tissues of the face
- dark red to purple discoloration and/or blistering of the comb
- dark red areas on the scales of the legs
- nasal discharge
- coughing, sneezing
- lack of coordination
- abnormal head and neck positions
What is the response if HPAI is detected in poultry?
HPAI is controlled by eradication as per United States Department of Agriculture (USDA) regulations, due to the severe nature of the disease if unchecked, as well as serious international trade implications for poultry and poultry products.
If HPAI is detected in a domestic poultry flock, disease control experts from the Pennsylvania Department of Agriculture (PDA) will initiate a quarantine of the infected flock premises. PDA officials, with USDA if requested, will oversee depopulation, disposal and clean-up activities on the premises.
All birds in the flock that have not yet died from the virus infection can be inventoried for indemnification purposes, and will be killed by approved methods to prevent spread of disease. Appropriate carcass disposal and thorough cleaning and disinfection of the poultry house and/ or other methods to ensure inactivation of virus will follow.
During this time, other flocks in a "control zone" within a few miles around the infected premises will be tested at intervals to detect any new infections. Once conditions are met to end the quarantine on a premises, including test results that indicate there is no viable AI virus in the environment, new birds can be brought in to start the next flock.
Can medications be used to treat birds infected with AI?
No. Antiviral medications are not permitted for use in poultry in the US. Antibiotic medications for poultry work against bacterial diseases, but have no activity against viruses. Likewise, medications to control parasites such as coccidia and worms, are specific for those organisms, and are ineffective against viruses.
Can vaccines be used in birds to prevent AI?
No- not at this time. In the past there has been occasional limited use of specific vaccines for LPAI. Although there are some commercially produced AI vaccines available now, none are an exact match for the current strains of virus of concern (HPAI H5) in the US, and USDA is not allowing their use.
Some new vaccine candidates specifically made to protect against the new strains are in the later stages of testing, and are proving to be highly protective in research trials. It is anticipated that vaccine will be made and stockpiled soon. If the 2015 HPAI H5 outbreak reemerges and progresses, there may be limited use of vaccine in specific circumstances under regulatory control to aid the ultimate goal of eradication of the HPAI virus.
Avian Influenza Testing and Diagnostics
What kind of samples are taken for testing of birds for AI?
The most common samples taken from birds for AI virus testing are swabs of the upper part of the mouth or trachea for most poultry (other than waterfowl), and swabs of the cloaca (vent area) for waterfowl (wild or domestic).
What tests are used to diagnose avian influenza in birds?
The most common test employed is the polymerase chain reaction (PCR) test, which is fairly rapid (results in 3 to 4 hours) and sensitive. One type of PCR test can detect the genetic material of any type of AI virus present in the sample, while other PCR tests are specific for the H5 or H7 subtypes. PCR is usually the first test used in an outbreak situation.
Virus isolation tests may also be conducted. The virus isolation test can take 7-14 days, but yields additional information on the virus.
For routine monitoring, there are reliable serology tests to detect antibodies to avian influenza antibodies in the serum of blood samples from the birds. Results of these tests can be obtained in 1 to 2 days.
What labs are authorized to conduct the tests for AI in Pennsylvania?
All 3 laboratory locations of the Pennsylvania Animal Diagnostic Laboratory System (PADLS) are certified to conduct the tests. They are the Pennsylvania State University Animal Diagnostic Laboratory at University Park, the Pennsylvania Veterinary Laboratory in Harrisburg, and the University of Pennsylvania New Bolton Center Laboratory at Kennett Square.
More information can be found on the PADLS website.
Confirmatory tests for an initial detection of certain strains of AI virus in the state are conducted at the USDA Animal and Plant Health Inspection Service (APHIS) National Veterinary Services Laboratories at Ames, Iowa.
Current HPAI H5 Outbreaks
Re: The Current US AI Problem
What has happened regarding bird flu in the US this year?
There have been infections of certain HPAI H5 viruses in multiple states since mid December 2014. The majority of the problem in poultry has been due to HPAI H5N2 in the the upper Midwest, notably MN and IA during March through mid June 2015. Turkeys and commercial layer chickens have had most of the infections in this outbreak. Just under 50 million birds were affected during the first 6 months of 2015. The last detection of HPAI H5 in a poultry flock was in Iowa on June 17, 2015.
Does the current HPAI H5 cause flu in humans?
At this time, there is no evidence that this virus is infecting humans. This is not human flu. The Center for Disease Control and Prevention assesses the risk of human disease from the current HPAI H5 as low. There have been no illnesses related to this virus in the farmers, owners, and other people who have been exposed to infected birds and premises during the current outbreak. However, precautions, such as using personal protective equipment, are in use for workers in these situations. This virus is different from the Asian HPAI H5N1 that has caused sickness and deaths in people overseas in recent years.
Does the current HPAI H5 cause flu in mammals such as pets and livestock?
At this time, there is no evidence that this virus is infecting pets, livestock, and other mammals. Some of these animals have their own type of flu that is different from bird flu. Turkeys are often susceptible to certain swine influenza viruses, and vice versa. In the Midwest this year, some swine in the areas of HPAI H5 positive poultry flocks were tested, and no evidence of infection has been found to date.
What is a "flyway" as it refers to wild birds, and where has HPAI H5 been found so far?
A flyway is a natural migration path for wild birds that migrate seasonally. In North America, these routes traverse the continent from breeding and rearing grounds in northern regions in the summer, to southern regions where overwintering occurs. There is some overlap of bird movements within these routes and destinations. There are 4 major flyways for wild waterfowl that span the US: Pacific, Central, Mississippi and Atlantic. So far in 2015 in the US, HPAI H5 has been found in 1 or more states in all flyways, except for the Atlantic.
Is the current US HPAI H5 in PA flocks now?
No. This virus has not yet been detected in Pennsylvania. The same can be said for other states in the northeast, mid-Atlantic, and southeast regions. The closest detections in poultry by straight line miles to a PA border have been in Ontario, Canada, north of Lake Erie.
Is HPAI H5 predicted to come to PA?
Unknown, but probably. Experts in wild waterfowl AI predict that the HPAI H5 virus will continue to circulate in this natural reservoir in North America for the next 4 to 5 years. It is highly likely that the wild waterfowl that will migrate south through the Atlantic flyway this fall will have encountered this virus over the summer in areas where their northern ranges overlap with birds from the Mississippi flyway. This fall and the next several fall and spring migration seasons are thought to present a significant risk for introduction of this virus.
What is being done to help prevent, limit HPAI H5 in PA?
In depth planning has been underway by Pennsylvania government, industry and academia since spring 2015. Preventing introduction to poultry flocks by implementing the highest levels of biosecurity is paramount to the process. If introduced, detecting infection rapidly and acting quickly and decisively using the best methods to control infection and recover from an outbreak, large or small, are the goals of this planning. Prior experiences with HPAI in PA in the 1980's and with several LPAI events in PA in the years since, and lessons learned from the Midwest in 2015 all provide valuable information that is being used for planning purposes.
Can I get avian influenza from eating poultry or eggs?
No. Poultry and eggs that are properly prepared and cooked are safe to eat. Proper processing, handling and cooking of poultry provides protection from viruses and bacteria, including avian influenza.
As we remind consumers each and everyday, there are four basic food safety steps to follow: Clean, separate, cook, and chill.
How can USDA assure consumers that avian influenza infected meat will not enter the food supply?
The chance of infected poultry entering the food chain is extremely low. As part of the USDA highly pathogenic avian influenza response plan, infected birds do not enter the food supply. Additionally, USDA's Food Safety and Inspection Service inspection program personnel are assigned to every federally inspected meat, poultry and egg product plant in America. All poultry products for public consumption are inspected for signs of disease both before and after slaughter. The "inspected for wholesomeness by the U.S. Department of Agriculture" seal ensures the poultry is free from visible signs of disease.
Does proper food handling prevent avian influenza?
Avian influenza is not transmissible by eating properly prepared poultry, so properly prepared and cooked poultry and eggs are safe to eat. The chance of infected poultry or eggs entering the food chain is extremely low because of the rapid onset of symptoms in poultry as well as the safeguards USDA has in place, which include testing of flocks, and Federal inspection programs. USDA works to educate the public about safe food handling practices in response to numerous questions from the public about the human risk associated with avian influenza.
What does proper food handling mean?
Proper handling and cooking of poultry provides protection against all avian influenza viruses, as it does against other viruses and bacteria, including Salmonella and E.coli. Safe food handling and preparation is important at all times.
USDA continually reminds consumers to practice safe food handling and preparation every day. Cooking poultry, eggs, and other poultry products to the proper temperature and preventing cross-contamination between raw and cooked food is the key to safety.
- Wash hands with warm water and soap for at least 20 seconds before and after handling raw poultry and eggs
- Prevent cross-contamination by keeping raw poultry and eggs away from other foods
- After cutting raw meat, wash cutting board, knife, and counter tops with hot, soapy water
- Sanitize cutting boards by using a solution of 1 tablespoon chlorine bleach in 1 gallon of water
- Use a food thermometer to ensure poultry has reached the safe internal temperature of at least 165 °F to kill foodborne germs that might be present, including the avian influenza viruses
Where can I get more information about safe food handling?
Consumers with questions about the safe storage, handling, or preparation of meat, poultry, and egg products, can call the USDA Meat & Poultry Hotline at: 1-888-MPHotline (674-6854). The hotline is available in English and Spanish and can be reached from 10 a.m. to 4 p.m. EST, Monday through Friday.
Also, "Ask Karen" is the FSIS virtual representative available 24 hours a day to answer your questions.
Small Flock Poultry Owners
(Pet, Hobby, Exhibition, Small Commercial)
Why are there no live poultry exhibits at the 2015 county fairs and the 2016 Farm Show?
The Pennsylvania Department of Agriculture (PDA) made this decision as a precautionary measure to protect your flocks, given the HPAI H5 bird flu problems in other parts of the US this year.
The suspension will block the risk of inadvertently introducing and spreading the disease by these activities. There is a need for extra biosecurity including keeping poultry at home during this time. The decision to resume these activities next year will be based on an updated evaluation of risk at that time.
My birds are healthy, are given good feed and water, and have ample space to roam. Won't that protect them from HPAI?
No. This is an equal opportunity disease. If any susceptible birds of the right species and age are exposed to an infectious dose of HPAI virus, they will get sick and most will die from the infection.
This is true for very small flocks, pastured flocks, large commercial flocks in total confinement, and every type of operation and management style in-between.
Have small flocks been affected with the HPAI H5 in the US?
Yes. 21 of the 223 total detections in domestic flocks from late 2014 to present have been in small, non-commercial flocks.
How can I protect my birds from getting AI?
Follow common sense biosecurity practices that isolate your flock from other birds. Also particularly important is maintaining separation of your birds from any possible contact with wild waterfowl (ducks, geese, swans) and shore birds (gulls, terns), and the water sources where these wild birds congregate. It is always advisable to raise land birds such as chickens, turkeys, guinea fowl, pheasants (birds with beaks) only, or aquatic birds such as ducks, geese and swans (birds with bills) only, and not both types together. This will help prevent the introduction and spread of AI viruses.
Where do I get help when I suspect I have a health problem in my poultry flock?
The Pennsylvania Animal Diagnostic Laboratory System has several University-based veterinarians with advanced training and expertise in poultry diseases.
Avian Influenza: Where to Get Help in Pennsylvania .
What else do I do when I suspect I have a health problem in my poultry flock?
If birds are dying, the dead should be double-bagged and refrigerated for possible testing. Meanwhile, until the problem is investigated further, diagnosed, and/or resolved, put your flock on 'voluntary quarantine". This means operating as a closed flock: Do not buy, sell, trade or otherwise move birds to or from your premise. Do not visit other flocks, poultry auctions, shows, or bring in visitors that have their own birds. These measures will help prevent potential disease- causing agents from being transmitted to other flocks, and new agents from being introduced into your flock.
Where can I get additional guidance regarding backyard flock biosecurity?
A comprehensive source of recommended practices that you can implement for your home flock is USDA Biosecurity for Birds website.
Waterfowl and Upland Game Bird Hunters
Should waterfowl and other bird hunters take precautions to prevent exposure to AI?
Yes. Hunters should follow common sense hygiene precautions when handling game, as is recommended at all times. These include:
- Do not handle, butcher or eat sick game.
- Wear rubber or disposable latex gloves while handling and cleaning game.
- Wash hands and thoroughly clean knives, equipment and surfaces that come in contact with game.
- Do not eat, drink or smoke while handling the birds.
- Cook the game thoroughly (minimum of 165 degrees internal temperature) before eating.
Can I feed waterfowl that I find or kill while hunting to other birds, pets, livestock?
No. Never feed sick or dead birds to any birds or animals. Do not feed the carcasses from "normal" (healthy) hunter-killed birds to raptors (falcons, owls and other birds of prey) or other captive birds. Do not feed the "normal" carcasses to mammals unless they are butchered, prepared and cooked to the same specifications as if intended for human consumption.
If you are a bird hunter who also keeps poultry at home, are there additional precautionary measures to follow?
Yes. Change out of your hunting clothes, shower and put on clean clothes before tending to your flock.
Maintain complete separation between the area where you bring in, clean and process your killed game and the areas where your poultry or other birds are kept. Ideally the game should be field- dressed well away from your property.
Where can I get additional guidance regarding hunters and AI?
See the USDA publication Guidance for Hunters--Protect Yourself and Your Birds From Avian Influenza.
Should I be worried about my song bird feeder?
There are no specific concerns about AI and feeding song birds In PA at this time. The only detection of HPAI in a song bird during the current outbreak was in a sick chickadee in Minnesota in the summer of 2015.
As a routine, you should always practice good hygiene when maintaining and filling the feeders. It is recommended that feeders be cleaned periodically with household detergent and rinsed thoroughly with clean water. Then do a final rinse with chlorine bleach solution (9 parts water to 1 part chlorine bleach) and allow to dry without rinsing further.