Aquatic wild birds represent the main reservoir for all naturally occurring influenza A virus subtypes (avian influenza, AIV: presently 16 H and 9 N subtypes). Within this host pool, AI viruses usually perpetuate without any significant consequences for their hosts. If there is possibility for exposure and host and virus have the necessary disposition, virus transmission from this reservoir to poultry and mammals – including humans – is possible.
In domestic poultry, AI viruses of the subtypes H5 and H7 can mutate spontaneously into highly pathogenic forms (highly pathogenic avian influenza viruses, HPAIV), which are the actual causative agents of classical fowl plague. Especially in chicken and turkey holdings, classical fowl plague causes massive losses and is therefore of high economic relevance. If humans are exposed to high infectious doses of HPAIV, but also some AIV which are low pathogenic in poultry (LPAIV), the virus can be transmitted and cause fatal disease in humans. This applies for example to HPAIV of the subtypes H5N1, H5N6 and the LPAIV H7N9 detected in China.
Prevention and control of classical fowl plague are regulated by national legislation. The emphasis is laid on biosafety measures to prevent an introduction of the pathogens into poultry holdings and their spread in the poultry population. Early detection of possible infections in poultry is of utmost importance; infectiological diagnostics play a decisive role. This concept also includes extensive monitoring of wild birds and poultry.
The NRL for AIV is the direct contact and reference center for federal and state authorities, especially for questions relating to diagnostics, and is also active within the European network of national reference laboratories. As reference laboratory of the World Organisation for Animal Health (WOAH) and of the Food and Agriculture Organization (FAO) of the United Nations the laboratory also provides advice and diagnostic assistance to countries outside Europe. The laboratory conducts application-oriented research in the field of AIV diagnostics, epidemiology and pathogenesis. Furthermore, the NRL intensively deals with scientific questions relating to porcine influenza.