Bird flu or Avian flu is caused by a type of influenza virus that is hosted by birds, but may infect several species of mammals. It was first identified in Italy in the early 1900s and is now known to exist worldwide. A strain of the H5N1-type of avian influenza virus which emerged in 1997 has been identified as the most likely source of future influenza pandemic.
Strains of avian influenza virus may infect other types of animals, including birds, pigs, horses, seals, whales and humans. However, the wild fowl act as natural asymptomatic carriers, spreading it to more susceptible domestic stocks. Avian influenza virus spreads in the air and in manure and there is no evidence that the virus can survive in well cooked meat.
How it is Diagnosed
Many poultry farmers may find it a bit hard to diagnose avian flu in their flocks. There are however symptoms they need to look out for and learn to recognize early.
Farmers should look out for the following symptoms in their flock
1. Ruffled feathers
2. Soft-shelled eggs
3. Depression and droopiness
4. Sudden drop in egg production
5. Loss of appetite – birds are not consuming lower feed than normal
6. Cyanosis (purplish-blue coloring) of wattles and comb
7. Edema and swelling of head, eyelids, comb, wattles, and hocks
8. Green diarrhea
9. Blood-tinged discharge from nostrils
10. Poor Coordination, including loss of ability to walk and stand
11. Pin-point hemorrhages (most easily seen on the feet and shanks)
12. Respiratory distress
13. Increased death OR high mortality losses in a flock
14. Sudden death
15. Nasal discharges
Poultry Vaccination is a strategy for controlling avian influenza in commercial poultry farms
Outbreaks of avian influenza in the poultry industry cause devastating or terrible economic losses for Poultry farmers. The disease is generally controlled through extensive culling of infected birds. Alternative strategies also use vaccination as a supplementary control measure during outbreaks.
ADVANTAGES OF VACCINATION
Vaccination is key to control of the disease as it reduces susceptibility to infection.
A higher dose of virus is necessary to infect the vaccinated birds.
Vaccinated birds shed less virus.
– Decreased contamination of the environment.
– Decreased risk of human infection
When used strategically, vaccination compliments a stamping out strategy by slowing/stopping the spread of the virus.
The influenza virus can survive for considerable lengths of time outside of the host and birds are infected through contact with other birds, mechanical vectors such as vehicles and equipment and personnel travelling between farms, markets and abattoirs.
Precautionary requirements include cleaning and disinfection of premises and the establishment of a Biosecurity barrier to help prevent spread of disease is essential.
Also, movement of farm workers should be restricted within the farm and poultry pens.