Causes and Transmission of Bird Flu
Bird flu is caused by influenza A viruses that naturally infect birds. These viruses are grouped based on two proteins found on their surface: hemagglutinin (H) and neuraminidase (N). Combinations such as H5N1, H7N9, and H5N6 are of greatest concern to humans. Learn more about the causes and transmission of bird flu below.
Bird flu is mainly a zoonotic disease, meaning it spreads from animals to humans. It does not easily spread between people, but mutations could change that in the future.
How it spreads:
- Bird-to-bird
- Infected birds shed the virus through saliva, nasal secretions, and faeces.
- It spreads quickly in crowded environments like poultry farms or live bird markets.
- Bird-to-human
- Most human infections occur through:
- Direct contact with infected birds (e.g., slaughtering or handling)
- Inhalation of droplets or dust from contaminated environments
- Touching contaminated surfaces or materials (e.g., bird cages, feathers)
- Contact with contaminated water, especially in open-air markets or farms
- Most human infections occur through:
- Human-to-human
- So far, rare and limited. A few cases of possible transmission between family members have been documented, but there’s no sustained chain of infection.
- Food safety
- Properly cooked poultry and eggs are safe to eat.
- The virus is killed by cooking at temperatures above 70°C.
High-risk environments:
- Poultry farms and abattoirs
- Live bird markets
- Wetlands or farms with wild bird contact
- Backyard chicken rearing without hygiene measures
In South Africa, outbreaks in birds have led to large-scale culling and surveillance by the Department of Agriculture. Migratory birds along the West Coast and inland wetlands are monitored during high-risk seasons.
Causes and Transmission of Bird Flu
Preventing zoonotic transmission involves strict biosecurity, personal protective equipment (PPE), safe farming practices, and immediate response to suspected outbreaks.
Monitoring and reporting are crucial, especially in areas where humans and poultry live in close quarters.
👉 [Next: Diagnosis and Testing for Bird Flu]
