Avian influenza, or 'bird flu', is a contagious disease of animals caused by viruses that normally infect only birds and, less commonly, pigs. Avian influenza viruses are highly species-specific, but have, on rare occasions, crossed the species barrier to
Avian influenza, or 'bird flu', is a contagious disease of animals caused by viruses that normally infect only birds and, less commonly, pigs. Avian i...
