The disease is directly transmitted by droplets inhaled from an infected personals sneezing or coughing or by indirect contact with contaminated objects, such as drinking glass.
The virus resists host antiviral cytokines, inducing excessive host pro-inflammatory responses. It may cause death by ‘cytokine storm’ rather than by inherent pathogenicity.
One type of bird flu is caused by the avian influenza A virus which can cause infection in birds and humans. Type A is the most virulent and usually affects young adults first and then spreads to the very young and very old in community.
The natural reservoirs of influenza A viruses – the etiologic agents of avian flu - are the aquatic birds of the world, particularly ducks, in which the viruses appear to be in evolutionary stasis or equilibrium with their natural host causing no disease.
Etiology of bird flu
