Bird flu is also called as Avian Influenza. It is a viral infection which spreads from birds to birds, birds to humans and other mammals. Most avian influenza viruses do not infect humans except A (H5N1) and A (H7N9).Wild water fowl such as ducks and geese are mainly affected with avian influenza.
Currently a highly pathogenic strain H5N1 is seen among the poultry in Egypt and in Asia. Humans catch these infections only from the infected birds. Person to person transfer is very rare or can be transmitted only through very close contact like a mother treating her infected child or a health worker with an infected person. Humans catch bird flu through close contact with infected birds or bird droppings such as the faeces, secretions from the nose or the mouth. Humans have also caught infection by swimming in water contaminated with the droppings of the birds or cleaning infected birds. Humans can also catch the infection by eating undercooked poultry or eggs.
Avian influenza virus is classified into 2 types based on their ability to cause disease in birds: high pathogenicity or low pathogenicity. High pathogenicity viruses result in high death rate and the mortality rate increases gradually. 100% mortality is observed within 48 hours of infection. Low pathogenicity viruses infects poultry but are not associated with severe disease conditions.