What is it?
Avian Influenza (AI, flu, Fowl Plague) is an infectious viral disease of many
avian species, including chickens, turkeys, gamebirds, ratites, waterfowl, pigeons
and wild birds.
What's the big deal?
AI is a very serious threat to all poultry industries: commercial, gamebird,
exhibition, waterfowl, ratites and pigeons. So serious that infected flocks
are quarantined and depopulated. State poultry shows, exhibitions and sales
can close. Quarantined zones can restrict the movement of all avian and possibly
livestock traffic. Other countries can ban receiving poultry exports from the
What are the signs of disease?
Variable - can be no symptoms, mild to severerespiratory signs (sneezing, snicking),
head swelling, combs turn blue, hemorrhages (red spots) on leg shanks, nervous
signs (can't walk, twisting of head and neck), diarrhea, decrease in egg production
and feed intake, low to high mortality (death) depending on strain. These clinical
signs are seen in quite a few viral and bacteria diseases, so a proper diagnosis
How is the disease diagnosed?
Through flock history, clinical signs, gross lesions, blood tests and virus
isolation from tracheal/cloacal swabs and bird organs performed at a diagnostic
How is the disease transmitted?
The virus is shed in nasal secretions and feces of infected birds. The virus
can then be spread by bird-to-bird contact, through infected manure, contaminated
equipment, vehicles, bird & egg crates and people whose clothing or shoes
have come in contact with the virus. Airborne spread may be possible if a high
concentration of virus is present. The virus can be killed with disinfectants
and drying, but if protected by organic material (manure, feathers, eggs debris,
etc.) it can survive for weeks.
How is the disease prevented?
Prevent introduction onto the farm by keeping a closed flock and practicing
biosecurity - disease prevention management - whether you have a commercial
poultry farm or own a few backyard chickens:
- People - Avoid visiting
other poultry farms or live-bird shows & markets. If you do, shower
and change clothing and footwear before working with your birds. Don't allow
people who have birds to visit your farm without showering and changing
clothes beforehand or have them wear protective clothing and footwear and
- Equipment - Do not loan
or borrow equipment or vehicles from other farms. If you have to, wash and
disinfect all equipment before and after use. Wash and disinfect your vehicle/trailers/crates
(including tires and undercarriage) after leaving a poultry farm, show or
market. Keep your houses/pens, equipment and work areas clean and sanitary.
- Birds - Keep a closed flock.
Do not bring birds from poultry shows & markets back to the farm - this
is a great way to introduce any disease. Separate new birds away from the
flock for 2-4 weeks to see if they show any signs of disease. Protect loose
backyard poultry from coming in contact with wild or migratory birds, which
can be carriers of the virus. Keep poultry away from lakes or ponds that
may have been contaminated by wild birds. Take sick or fresh dead birds
to a diagnostic lab to determine cause of illness/death.
- Rodents, wild birds - keep
your rodents and wild birds away from your poultry buildings/cages. Use
rodent bait stations, keep the grass cut, pick up garbage piles and don't
allow wild birds to build nests around your poultry area.
Can people get infected with Avian Influenza?
Only one strain of High-Pathogenic Avian Influenza (H5N1) has shown to be infectious
to people. This strain was found in Hong Kong in 1997 and to date hasn't been
found outside of Hong Kong.
Julie D. Helm, DVM
Clemson University Livestock