Surveillance, early detection, biosecurity, planning—key to defense against Asian bird flu
Article originally published in the Delmarva Farmer
Avian Influenza is causing significant concern in the agricultural community and the general public. One specific type of avian influenza, commonly called the Asian bird flu, or more scientifically, H5N1 highly pathogenic avian influenza (H5N1 HPAI), is causing the most concern. It is deadly to poultry and is spread by wild birds. Over the last several months, this flu virus has spread from Asia to many countries in Europe, Africa and the Middle East via infected migratory birds which are primarily waterfowl. Waterfowl using the East Asia Flyways migrate through highly infected Southeast Asia. The northern latitudes of the East Asia Flyways overlap the Pacific Flyways in Alaska. Because Alaska is at the cross roads of these bird migration flyways, scientists believe if the Asian bird flu arrives in the United States via migratory birds, it is most likely to arrive in our northern-most state first.
Avian influenza is first and foremost a disease of wild birds which has serious consequences if introduced into commercial poultry. Although H5N1 HPAI poses a potential threat to our commercial poultry industry, as well as our economy, the transmission of H5N1 HPAI from birds-to-humans is extremely rare and virtually all infected people have had close direct contact with poultry infected with Asian bird flu. It is true avian influenza can and does mutate; unfortunately, no one can predict if and when this H5N1 strain of influenza will mutate and become capable of being readily transmitted from human to human.
Regardless, the agricultural community must be prepared whether or not this change occurs. The Delmarva strategy has four major parts: surveillance/early detection, biosecurity, planning, and training/preparedness.
The first line of defense is surveillance and early detection. In January 2006, the U.S. commercial chicken industry initiated an avian influenza testing program. All commercial broiler flocks in the U.S, from participating companies, including those from all four broiler companies on the Delmarva Peninsula, will be tested to ensure all poultry are free of avian influenza and confirmed AI negative, before going to the food processor. Additionally, on Delmarva, a locally developed surveillance program requires birds from any flock with slightly elevated mortality to be sent immediately for AI testing to the University of Delaware’s Lasher Laboratory in Georgetown, or the Maryland Department of Agriculture’s Animal Health Laboratory in Salisbury. These laboratories are equipped with real-time reverse transcription polymerase chain reaction (real-time RT-PCR), a highly sensitive, specific and rapid test for avian influenza.
The testing of migratory birds is being significantly increased in 2006. The USDA, the Department of Interior and its cooperators (including the State of Delaware and the University of Delaware) plan to collect and test between 75,000 to 100,000 samples from live and dead wild birds and an additional 50,000 samples of water and feces from high-risk waterfowl habitats across the U.S.
Biosecurity is the second line of defense—a measure long practiced in the poultry industry. Disease prevention is a priority at all times, and poultry growers understand the necessity for biosecurity practices. This is especially critical for owners of backyard flocks, since these birds are sometimes raised outside, and may come in contact with wild birds and migratory waterfowl. Restricting access to your property and birds minimizes the risk of infection. If you have come in contact with wildfowl or other birds, bath and change your clothes and footwear before caring for your birds. Hunters must be particularly aware of where they have been and how they may interact with domestic poultry. Also growers should know the warning signs of disease and report sick birds. If you are a grower, report any sick birds to your flock supervisor. If you have a back yard flock, call your state department of agriculture or the USDA’s toll-free hotline (1-886-536-7593) to report sick birds.
The live-bird markets represent another significant biosecurity risk. The markets are tested by the USDA and Delmarva has additional surveillance underway to prevent persons from stealing chickens from commercial chicken houses and selling them through the New York/New Jersey live-bird markets. Contact with these markets, equipment and personnel pose a real risk to the local chicken industry. Delmarva Poultry Industry, Inc. (DPI) has a toll free hotline (1-888-FLU-COPS) that persons can call to report suspicious or risky behavior involving commercially raised chickens and backyard flocks. Registration of poultry flocks is now required in Delaware and Maryland so that authorities can more easily notify owners if there is an outbreak and/or a need to quarantine flocks in a given area.
The USDA has increased biosecurity by imposing restrictions on the importation of poultry and poultry products to prevent the introduction of H5N1 into the U.S. This includes prohibiting the importation of live birds and hatching eggs from H5N1 HPAI affected countries. It also requires all imported birds (from non- H5N1 affected countries) to be quarantined at a USDA bird quarantine facility and tested for AI before entering the U.S. In addition, international travelers are being checked for illegal importation of live birds and illegal poultry products to reduce the chance that H5N1 can enter the country.
Planning is another key aspect of preparedness. The USDA has published an “Interim Avian Influenza (AI) Response Plan” in January 2006 and the U.S Government has developed a National Strategy for Pandemic Influenza involving the Departments of Agriculture, Health and Human Services, Interior and Homeland Security.
Locally, the low pathogenic avian influenza (LPAI) outbreak out on Delmarva in 2004 was limited to 3 farms. Good planning, fast action, prompt diagnosis, the effective use of poultry farm quarantine, rapid depopulation, in-house composting and proper decontamination stopped the spread. Team work among the state governments, the poultry industry, the Delmarva Poultry Industry, Inc. (DPI) and the Universities of Delaware and Maryland made this work so well. In fact, according to DPI, Delmarva’s efficient response and control has been called a “national model” by high ranking USDA officials.
The diagnostic laboratories in Delaware (Lasher and Allen Labs) and Maryland were especially important in this effort. Their use of the latest technologies to detect AI and their immediate response to the emergency, not only helped control the outbreak, but helped eradicate the disease quickly. The experience gained during that outbreak will be extremely useful in dealing with future out breaks. Delmarva’s Emergency Disease Task Force Committee, consisting of representatives from the team mentioned above, has probably produced the best emergency disease response plan in the country.
Outbreak training and preparedness are also very important. Through funding provided by a grant from the USDA, experts from the University of Delaware and the University of Maryland have been traveling across the U.S. and Canada training representatives of the poultry industry and local/state/federal agencies on how to handle AI, if and when it is detected on a farm. The program covers biosecurity and safety precautions; options for depopulation, disposal options including in-house composting, as well as, material and labor requirements. A training exercise, held in February, by the Department of Homeland Security, brought together the different agencies that would be involved in an AI outbreak on Delmarva.
Research leading to new technologies can be an important. During an outbreak, the best control measures to prevent the spread of virus to other farms are quarantine and depopulating infected poultry flocks. The most effective techniques to minimize human and animal health concerns will be used. Recently, at the University of Delaware, commercial scale foam generating equipment designed for depopulating broilers was field tested successfully. This and other foam generating equipment have proven to be rapid and effective in depopulating broilers. With increasing concern over human health risks during an AI depopulation event, this technique offers the potential to greatly reduce the number of responders needed thus limiting human exposure to the virus.
If an AI outbreak should occur, the Delmarva region is the best prepared. For further information please visit these websites:
