What is this A(H7N9) virus?
H7N9 is a subtype of influenza virus. H7N9 viruses have been previously detected mainly in wild birds, though other H7 viruses been reported around the globe in domestic and wild birds. The recent event in China represents the first ever report of H7N9 virus in humans.
What are the main symptoms of human infection with influenza A(H7N9) virus?
Thus far, patients with this infection have had severe pneumonia. Symptoms include fever, cough and shortness of breath. However, information is still limited about the full spectrum of clinical signs due to infection with influenza A(H7N9) virus.
How is this A(H7N9) virus associated with animals?
Chinese authorities have officially reported their detection of this H7N9 virus in bird samples collected from chickens, quails and pigeons at live bird markets in areas where humans have been affected.
The only previous reports of infections with this virus in Asia in animals come from 2008 events in the Republic of Korea and Mongolia where H7N9 subtype was isolated from wild birds.
It is important to note that H7 viruses and their subtypes (e.g. H7N2, H7N6, and H7N7) have been identified in poultry all over the world.
What is the source of the A(H7N9) virus that is infecting humans?
The source of infection has not yet been confirmed. A number of the human H7N9 cases in China have reportedly had contact with domestic poultry.
The Chinese authorities are conducting an extensive surveillance programme in domestic livestock in provinces where human cases have been found to gather further information.
The genetic analysis of the viruses isolated show components that are avian in origin, but the precise source of these human infections has yet to be determined.
