Answer:
Influenzavirus A uses wild aquatic birds as hosts. Occasionally it is transmitted to other species and may then cause devastating outbreaks in domestic poultry, or give rise to human influenza pandemics. The type A influenza viruses are the most virulent human pathogens among the three influenza types and cause the most severe disease.
First answer by PublicToilet. Last edit by PublicToilet. Contributor trust: 17 [recommend contributor recommended]. Question popularity: 19 [recommend question].