Avian and Human Influenza Virus Receptors and Their Distribution

Abstract

Influenza is one of the most widely distributed zoonotic infectious diseases in the world, and its pathogen, the influenza virus, is extremely mutable. Currently, the highly pathogenic avian influenza subtype H5N1, which is continuing to spread across Asia, Europe, and Africa, has already been transmitted into humans and has been generating mutation for possible propagation from human to human [1–8]. When this new variant of the virus becomes an epidemic among humans, it will spread throughout the world in a short time, resulting in a pandemic because humans do not have immunity to the virus. The avian influenza virus is rarely directly transmitted to humans in nature. Conversely, human influenza virus could not successfully infect ducks experimentally [1, 3, 4]. In other words, the host range of influenza viruses is changeable, wherein each virus is primarily prescribed with receptor binding specificity. In nature, receptor binding specificity changes due to mutations of the viral spike hemagglutinin molecule, resulting in transmission to other animal species across the host range.