Immunization-Schedule.com

Avian influenza or as more commonly called the bird flu is caused by the Avian Influenza A (H5N1) virus that is naturally found in the intestines of many wild birds. These wild birds do not fall sick from the virus. However, if the virus comes in contact with any domesticated bird, it can spread quickly from one infected bird to the other and kill a large number of birds in just a couple of days.