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Preparing for Avian Influenza 'Worst-Case Scenario'

The highly pathogenic avian influenza (HPAI) outbreak of winter and spring 2015 was the worst animal disease outbreak in U.S. history, affecting more than 48.8 million turkeys and chickens in 21 states, and causing economy-wide losses of an estimated $3.3 billion. Since the last detected case occurred on June 17, the U.S. Department of Agriculture's Animal and Plant Health Inspection Service (APHIS) has prepared for the disease to return this fall as wild birds begin to migrate south for the winter.

According to USDA, genetic analysis has shown that this year's HPAI viruses were the result of migratory birds in the areas between northeast Asia and Alaska comingling, allowing Asian HPAI strains to mix with low-pathogenic avian influenza (LPAI) strains already found in North America.

Wild birds, particularly dabbling ducks, appear to be the predominant host for these viruses. This month, those ducks will begin to fly south for the winter, potentially spreading HPAI to domestic birds along the Pacific, Central, and Mississippi migratory bird flyways.

This week, APHIS published the Fall 2015 HPAI Influenza Preparedness and Response Plan, which focuses on preventing or reducing future outbreaks, enhancing preparedness, improving and streamlining response capabilities, and preparing for the potential use of AI vaccines. It includes a biosecurity self-assessment for poultry producers, updated information on indemnity and other payments, and a draft vaccine use strategy.

The report says that in a worst-case scenario, HPAI could occur simultaneously in multiple sectors of the poultry industry throughout the U.S., with 500 or more commercial flocks being affected in Alabama, Arkansas, California, Delaware, Georgia, Indiana, Iowa, Kentucky, Maryland, Michigan, Minnesota, Mississippi, Missouri, Nebraska, North Carolina, Ohio, Pennsylvania, South Carolina, Texas, and Virginia.

Click here to read the complete report and access other HPAI documents from APHIS, including emergency response procedures.

In addition to USDA's preparations, states and producers have been preparing for a potential fall outbreak. "Minnesota's turkey farmers have been working hard to prepare for any future introductions of highly-pathogenic avian influenza," says Lara Durben, a blogger for Women in Ag and the communications director for the Minnesota Turkey Growers Association, Chicken and Egg Association of Minnesota, and Midwest Poultry Federation. "The USDA's plans are consistent with what have been our three major areas of focus: rapid response to an outbreak, strengthening biosecurity in and around our farms, and wild bird surveillance."

Begin With Biosecurity

While HPAI is mainly spread from wild birds to commercial flocks, considering the number and proximity of farms affected earlier this year, APHIS research shows it is likely spread in other ways as well. USDA recommends that producers immediately implement biosecurity measures to minimize the chance of the virus entering their poultry houses.

According to the USDA's report, Enhanced Biosecurity for Poultry Producers, the highest risks for virus introduction are personnel who enter poultry buildings, shared equipment and crews, improper disposal of dead birds, and mismanagement of manure.

The report recommends commercial operations add a biosecurity officer and implement a line of separation for each building, and a perimeter buffer area. The link above includes an online self-assessment to help producers come up with a biosecurity plan specific to their operation.

Early Detection Is Key

Both wild and commercial birds are being closely monitored for a new outbreak.

"As we near the beginning of the fall season, APHIS is confident that its surveillance programs in commercial and wild birds, which are the strongest in the world, will enable us to detect the disease early. APHIS' advanced planning and the preparations undertaken by the States and the poultry industry will help quickly contain the disease," APHIS said in a press release.

All 50 U.S. states and five territories responded to an APHIS survey over the summer, and the agency determined that the 20 "worst-case scenario" states have all made "significant efforts in implementing detection, preparedness, and response capabilities for future HPAI cases." Those 20 states have also implemented increased biosecurity practices.

Producers also need to monitor their own flocks, and are asked to report sick or unusual dead birds to a veterinarian or state animal health official, or call 1-866-536-7593. If AI is suspected, samples will need to be collected and sent to a laboratory.

The warning signs of infectious bird disease include:

  • Sudden increase in bird deaths
  • Sneezing, gasping, coughing, and nasal discharge
  • Watery, green diarrhea
  • Lack of energy and poor appetite
  • Drop in egg production or soft, thin-shelled, or misshapen eggs
  • Swelling around the eyes, neck, and wattle
  • Purple discoloration of the wattles, combs, and legs (AI)

If HPAI is Found

If testing confirms avian influenza, the producer will be contacted by a veterinary medical officer, and USDA will provide caseworker assistance for going through the next steps. Since the outbreak earlier this year, APHIS has added a fifth Incident Management Team (IMT) for conducting response operations, and added deployable personnel to respond to potential outbreaks. The agency has also enhanced training, safety, and IT support for responders.

If a flock does test positive for avian influenza, a USDA or state official will complete a flock inventory, and will follow the 5-step USDA plan for containing HPAI:

  1. Quarantine: Restrict movement of poultry and equipment.
  2. Eradicate: Humanely euthanize affected flocks within 24 hours of detection.
  3. Monitor: Test wild and domestic birds in a broad area around the quarantined site.
  4. Disinfect: Kill the virus in affected flock locations.
  5. Test: Confirm the poultry farm is AI virus-free.

Carcasses will be disposed by either in-house composting, outdoor on-site composting, burial, off-site composting, landfill, or incineration. The method will depend on the size of the flock, local conditions, and laws and regulations.

To clean affected buildings, all organic material is removed, all items are washed with detergent, rinsed, and allowed to dry. A disinfectant is then applied, and later surfaces are again rinsed and allowed to air dry. The building must remain empty for a minimum of 21 days, or until an APHIS official releases it from quarantine.

Looking Forward to a Vaccine

This week, Harrisvaccines was granted the first USDA conditional license for avian influenza. (Click here for full story.) This is the first step in getting a vaccine to market, but USDA will still have to authorize the vaccine before it is made available to producers.

"Although we cannot sell the vaccine today, we are in a better position to apply this robust and rapidly produced vaccine, if and when the virus reemerges once again," says Joel Harris, VP of Harrisvaccines.

"We are pleased that the process for a viable avian influenza vaccine continues to move forward," Durben says. "While a vaccine is not by any means a silver bullet to any future introductions of this virus, we believe it is important to have this available as another tool in the toolbox if it's needed."

The Personal Toll of HPAI

"Avian influenza has had a tremendous economic impact on the poultry industry and its farmers," Durben says. "But far worse, in my mind, are the emotional scars left behind. Farmers with no choice but to put down their healthy birds because the virus hit one of its barns; farmers who can't sleep at night, wondering if their flock is next; farmers who finally restock their barns after an outbreak but who worry day and night if avian influenza will come back."

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