Bird flu or avian flu is a highly contagious viral infection that is transmitted between birds and, on rare occasions, from birds to humans. Increasingly pathogenic mutations are leading to the emergence of more dangerous strains.
In humans, the symptoms of avian flu are similar to those seen in other types of flu. Some of these symptoms include the following:
- Fever of 38 ˚C (100.4ºF) or above
- A dry cough
- Muscle pain
- Limb and joint pain
- Chills and shivering
- Sore throat
- Runny nose
- Blocked nose
- Difficulty sleeping
- Loss of appetite
- Diarrhoea and stomach upset
The period between the time of infection and the appearance of symptoms is referred to as the incubation period and is usually between three and five days, but may extend to a week.
If left untreated, avian flu can cause rapid deterioration and serious complications. Some examples include:
- Pneumonia or inflammation of the lung tissue
- Acute respiratory distress syndrome, where the lungs cannot provide adequate amounts of oxygen to meet the body’s needs
- Multiple organ failure
The mortality rate associated with highly pathogenic H5N1 is high, at 60%, according to the World Health Organization estimate.
Reviewed by Sally Robertson, BSc