Managing avian influenza in the US

Fast lab results and the quick depopulation of live birds are imperative if avian influenza is suspected on your farm. This was one advice voiced during a ‘lessons learned’ program during IPPE in Atlanta, Georgia.

“When you are suspicious, it is very important to have fast lab results and quick depopulation of live birds if the results are positive. As the disease progresses through a farm, the environmental contamination grows and promotes the spreading,” said Dr Jill Nezworski, Blue House Veterinary, during her presentation at the ‘Highly Pathogenic Avian Influenza – Lessons Learned’, education program.

Early v’s late detection of avian influenza

At the event, sponsored by the US Poultry & Egg Association and United Egg Producers, Nezworski discussed ‘Lessons Learned in the Layer Industry’ in which she provided comparisons and contrasts between early detection of highly pathogenic avian influenza (HPAI) on farms and late detection due to mortality.

Nezworski observed that diagnosis of HPAI should be communicated to employees in an organised chain of command, and every hourly employee must also be educated and empowered. She remarked that, “False alarms may come up, but it is more important to create a culture in which it is fine to be wrong or over cautious.”

Good management is key

She also discussed key lessons, such as the disposal of birds being held in a secure spot and the need for extra people. She emphasised that it is essential to have a quick and realistic depopulation plan, as well as a primary plan and a backup plan for carcass disposal. After depopulation is over, she underscored the need for the entire site to be decontaminated with the thought that even outside premises still likely accumulate viral contamination. Nezworski stressed that big risks should be addressed, and management should make it hard for the system to fail.

During his presentation on ‘Lessons Learned in the Turkey Industry’, Dr Ben Wileman, Ag Forte, reflected that a clear sign of HPAI on a turkey farm is when a person enters the house and the turkeys are quiet. Wileman observed that when sick, animals develop neurologic signs, twist their necks and have tremors. He recommended, “When in doubt, test it.”

Timely depopulation is critical

Once avian influenza is detected, Wileman stressed that timely depopulation is critical. He commented that biosecurity has to be both physical (i.e.: walls, fences, boots, etc.) and operational (i.e.: showers, clothing changes, etc.) in procedure. In order to really work, biosecurity has to be effective and practical.

Dr. Lindsey Garber, USDA APHIS, Veterinary Services, provided an overview of the ‘Epidemiology of the Recent AI Outbreak’ that addressed the results of two studies, one with HPAI infected layer farms and the other with turkeys. The two studies concentrated on potential risk factors for the spread of HPAI, including rendering and garbage trucks, shared equipment use, visitors, wild bird presence, etc. The result from both studies centered on the need for effective and efficient biosecurity measures at all levels.

Vaccination to control HPAI

Dr David Swayne, USDA ARS, Southeast Poultry Research Laboratory, focused his presentation on the use of vaccination to control HPAI. He showed that vaccination does not completely protect birds from infection by HPAI, nor completely prevent s infected birds from shedding the virus. For these reasons, vaccination cannot be used alone to eradicate HPAI during an outbreak.

He pointed out that it can be used as a tool, along with depopulation and disposal, to potentially help slow down the spread of the virus. Swayne discussed countries that have tried to control HPAI by only using vaccination and noted that those countries have created an environment in which the virus can become endemic.