Avian Influenza, also known as Bird Flu or AI, is an often acute viral multisystemic disease of birds caused by Avian Influenza Virus Type A. This virus is borne naturally by water birds such as ducks and occasionally by wild and exotic birds, in which no clinical signs are shown, but could be a source of infection to other domestic birds. The disease spread between farms due to breaches in biosecurity practices, principally by moving infected poultry or contaminated faeces and respiratory secretions on farming equipment, clothes, boots, and other fomites. Airborne dissemination/spread is also possible between farms within close distances. There is limited spread by wild birds in some strains of the virus. In this post, we will discuss the signs of Avian Influenza, preventive measures to reduce the risk of infection, and available treatments.
When to Suspect Avian Influenza
The Avian Influenza virus has strains that have low, medium, and high pathogenicity and this influences the severity of the clinical signs.
Low Pathogenic Strain Clinical Signs
- Respiratory signs such as sneezing, coughing, ocular and nasal discharge, and swollen infraorbital sinuses in poultry
- In layers and breeders, there may be decreased egg production or infertility, ova rupture (evident as yolk present in the abdominal cavity), or involution, mucosal oedema, and inflammatory exudates in the lumen of the oviduct.
- A few layer and breeder chickens may have acute renal failure and visceral urate deposition (visceral gout)
Note that the clinical signs may be indistinguishable from New castle disease
High Pathogenic Avian Influenza
- In acute cases, lesions may include bluish discoloration (later dark spotting) and swelling of the head, comb, wattle, and snood (turkey);
- Red discolouration of the shanks and feet
- Blood spots on organs and muscles; and blood-tinged oral and nasal discharges.
- In severely affected birds, greenish diarrhoea is common
- Birds that survive acute cases may develop nervous signs like paralysis, neck twisting, etc
Prevention of Avian Influenza
The following Bio-security measures can be put in place to prevent outbreaks of AI in poultry:
- Use of licensed AI vaccine
- Disinfection (Foot dips, vehicle and human disinfection at the entrance to the farm, drinking water sanitization). Recommended Disinfectants are V-OX, Polidine, and Vinkoquat.
- Quarantine of new birds with a separate handler.
- Restriction of movement into and around the farm.
- Control pests and wild birds around the farm.
- Check that all materials coming into the farm are from trusted origins e.g feed trucks, egg crates, building materials, etc
- Boost the immunity of birds routinely with multivitamins, particularly Vitamins C
Treatment of Avian Influenza
Like most viral diseases, bird flu has no specific treatment, however, it can be managed using broad-spectrum antibiotics to control secondary pathogens and boost the immunity of the birds with the use of multivitamins. Increasing house temperatures may also reduce morbidity and mortality.
To put it briefly, Avian influenza represents a major threat to poultry farming. While there is no single solution to treat avian influenza, careful management practices can help reduce the risk of infection. For poultry farmers, good biosecurity and hygiene and increased surveillance are all important steps in protecting against this disease. While avian influenza remains a challenge for the industry, understanding the signs and treatment protocols can help mitigate its impact on poultry farms.