by Sally Colby
Those who raise poultry, either as a small-scale farm enterprise or a large commercial operation, are likely aware of recent cases of avian influenza diagnosed in the U.S.
AI is classified as either low pathogenic (LPAI) or highly pathogenic (HPAI). Cases of HPAI have been reported in commercial and backyard flocks in New York, Maine, Virginia, North Carolina and Delaware.
HPAI is widely found in wild migratory waterfowl such as geese, ducks and shorebirds. After these birds ingest the virus, it replicates in the digestive tract and is shed in feces. There’s also evidence of some replication in the respiratory tract. Although wild waterfowl infected with HPAI don’t necessarily show signs of illness, they’re responsible for transmitting the disease to domestic poultry. A dime-sized pat of feces from an infected goose is enough to contaminate an entire house of birds.
One of the best ways to prevent HPAI in domestic poultry is understanding the role of fomites in disease transmission. A fomite is an object or material that can carry and transmit infection and can include a child’s wagon, tractors, farm truck, boots, the feet of a farm dog or even your own hands.
Knowing that the feces of wild waterfowl potentially harbor HPAI, think of the many ways disease can spread via fomites. A quick trip to the feed or farm supply store might be what introduces HPAI to your flock simply due to the risk of others in the store who may have infected poultry at home or who stepped in infected feces prior to entering the store. Disinfect your own shoes with an effective viricidal product such as Lysol before getting in your vehicle and again before exiting the vehicle at home.
If someone brushed the sole while tying their shoes and then opened the door and deposited a bit of feces on the door handle prior to you touching it, that’s another potential scenario for transmitting HPAI. The spray can of disinfectant should be accompanied by hand sanitizer, and both should be kept in your personal vehicle, farm use vehicles, tractors, at the door to your home and anywhere else it might be needed.
To limit your flock’s exposure to HPAI, establish a perimeter buffer zone outside of poultry housing that separates equipment and handling materials from the rest of the farm. Post signs to ensure all are aware of the zone. All bird-handling activities should take place well inside the buffer zone.
For those raising poultry outdoors, the best defense is to be aware of seasonal migratory waterfowl patterns and if possible, keep birds inside during heightened wild fowl movement. Feces from HPAI birds can remain infective for weeks on just about any surface, including the ground. Follow the same biosecurity protocols as confinement operations and be aware of how easy it is to transfer fecal material from wild waterfowl to your domestic flock.
Many farm properties include a pond or other body of water where waterfowl congregate. If possible, discourage waterfowl from taking up residence. Swans are territorial and are usually aggressive toward geese, so a swan decoy on the pond may help deter them. Geese prefer open spaces near a pond for landing and takeoff, so vegetation can discourage them from inhabiting a pond. Commercially available products can be spread around the edges of ponds and around buildings to discourage geese. Dogs can be used to deter geese, but be aware that dogs’ paws can easily pick up feces and track it to other areas of the farm.
Be aware of anything on the farm, especially feed, that attracts wildlife and reduce those attractions. It’s good basic biosecurity to manage rodent populations and exclude wild birds from perching and roosting in eaves.
Maintain a strict visitor policy for the farm. Ideally, if HPAI is known to be present in the region, those who have poultry at home should not visit another farm with poultry. If that measure is unavoidable, guests to the farm who have poultry at home should disinfect their shoes prior to exiting their vehicle and again prior to leaving, and should not visit areas where poultry are housed. However, keep in mind that a visitor who doesn’t have poultry at home could still introduce HPAI to your farm via footwear or other fomites.
Employees should be well-trained to follow biosecurity protocols and should follow protocols consistently. Provide PPE for anyone handling birds or entering poultry buildings. PPE should be worn only while working with poultry and always changed between buildings. Employees should be trained to recognize early signs of illness in birds and should be aware of any potential breaches in biosecurity.
Be sure everyone in the family understands biosecurity basics and how fomites spread disease. The tread on the tires of an ATV can easily pick up bits of feces, so if the rider checks the tires that may have picked up waterfowl feces then rides for a while, the tires and the handlebars – and even the rider’s hands – are potential fomites. In much the same manner, geese flying over a skid steer or tractor parked outside a poultry barn can deposit HPAI feces, then when the operator gets in to move feed, contamination occurs by way of the vehicle acting as a fomite.
Prior to working with your own flock, wear clean clothing, disinfect your shoes or boots and wash and sanitize your hands. After completing chores, disinfect footwear, change to clean clothing and keep exposed clothing separate from other laundry. Wash and sanitize hands after changing clothes and between tasks. Be sure to remove excess organic matter from boots, clothing, tools, vehicles and other exposed equipment prior to sanitizing.
The key to preventing HPAI is a good biosecurity program that includes awareness of the role of fomites in disease transmission. Be aware of risks, control what you can control, watch for the presence of migratory waterfowl and take whatever measures necessary to ensure your flock remains healthy.
To help stop the spread of HPAI, watch closely for illness in your own flock, work with your veterinarian to ensure good biosecurity is in place and report any sick birds to the USDA at 1.866.536.7593.