Avian influenza revisited: concerns and constraints.

Avian influenza (AVI) is being known for its pandemic potential and devastating effects on poultry and birds. The AVI outbreaks in domesticated birds are of concern because the Low pathogenic avian influenza virus (LPAI) tends to evolve into a High pathogenic avian influenza virus (HPAI) resulting in the rapid spread and significant outbreak in poultries. The containment should be rapid and stringent precautions should be taken in handling the infected poultry cases or infected materials. In general, AVI viruses do not replicate efficiently in humans, indicating that transmitting these viruses to humans directly is a very rare preference. However, the HPAI ability to the cross-species barrier and infect humans has been known for H5N1 and H7N9. Recently, the world's first human case of transmission of the H5N8 strain from the avian species to humans has been documented. In this recent scenario, it is worth discussing the strain variations, disease severity, economic loss, and effective controlling strategies for controlling avian influenza.