Avian influenza

H5N1 avian influenza virus particles, TEM. © Science Photo Library

Influenza is an infectious disease that primarily presents with respiratory signs and symptoms, caused by RNA viruses. The most significant impacts of influenza viruses on humans are those arising from the influenza A strains. The natural reservoir of influenza A strains is a diverse pool of viruses among aquatic wild bird populations, the avian influenza (AI) viruses. These viruses are divided into those of high and low pathogenicity (hence HPAI and LPAI), according to their severity in the avian species they usually infect. HPAI epizootics continue to be documented worldwide all due to the A/H5 and A/H7 virus groups. Read more facts about avian influenza in humans

Other types of influenza

Disease / public health area

Pandemic influenza

A pandemic is the rapid spread of a new human influenza around the world. Influenza pandemics happen when a new strain of a flu virus appears which can infect humans, to which most people have no immunity and which can transmit efficiently from human to human.

Disease / public health area

Seasonal influenza

Seasonal influenza is a preventable infectious disease with mostly respiratory symptoms. It is caused by influenza virus and is easily transmitted, predominantly via the droplet and contact routes and by indirect spread from respiratory secretions on hands etc.

Disease / public health area

Swine influenza

Swine influenza is a respiratory disease of pigs caused by type A influenza viruses that regularly cause outbreaks of influenza in pigs. Influenza viruses that commonly circulate in swine are called “swine influenza viruses” or “swine flu viruses.” Like human influenza viruses, there are different subtypes and strains of swine influenza viruses.