Now that we know about both prokaryotic and eukaryotic cells, let's look at the endosymbiosis theory. This theory suggests that mitochondria and plastids in eukaryotic cells were once independent prokaryotic cells.
Avian influenza (AI) is an infectious viral disease of birds (especially wild water fowl such as ducks and geese), often causing no apparent signs of illness. AI viruses can sometimes spread to domestic poultry and cause large-scale outbreaks of serious disease.
Top Tools & Guides. Avian Influenza. Avian influenza (or bird flu) is a lung and airway disease found in birds, and it is caused by the influenza virus. This viral infection can also spread to humans, so if your bird is infected, seek immediate treatment and take all necessary precautions to prevent an outbreak of bird flu.