Diseases Transmitted by Animals: Swine Flu is so termed because the virus that first caused the disease had originated from pigs. People with weak immune system are at high risk of contracting swine flu. It is an acute respiratory virus which is contagious and spreads through air. Swine flu is caused by virus that affects pigs and has started infecting humans as well. Influeuza virus FI1N1 has been identified as the cause of this disease.
Avian influenza is a contagious bird disease caused by a number of viruses. Birds that can carry and spread an avian influenza virus include poultry (like chickens, turkeys or ducks), wild birds and even pet birds.