Several German states have reported increased mortality among cranes in recent days. Investigations by the relevant state testing facilities have revealed strong indications of avian influenza virus infection ('bird flu'). The Friedrich Loeffler Institute (FLI) has now confirmed the suspicion of infection with the highly pathogenic avian influenza virus (HPAIV, bird flu) of the H5N1 subtype in crane samples sent in from Mecklenburg-Western Pomerania, Brandenburg, Saxony-Anhalt and Thuringia. Avian influenza is a highly contagious infectious disease that is rapidly fatal in many bird and poultry species. Further investigations to characterize the viruses in detail are currently being carried out. Sequence analyses to date indicate a variant of the H5N1 strain that has been dominant in Europe in recent months. Due to the current high migratory activity of crane populations and other wild birds, further, possibly widespread, spread of HPAIV infections must be expected in the near future. In its current risk assessment, the FLI has therefore reassessed the risk of further outbreaks in poultry farms and cases in wild birds as “high.”
The FLI is currently observing a renewed increase in HPAIV H5N1 infections in various wild bird species, and the number of HPAIV outbreaks in poultry farms has also risen sharply in the last two weeks.
The cranes with currently striking cases are not the only wild bird species affected; other wild waterfowl species such as ducks or geese may show milder symptoms of HPAIV infection, partly because they may have already developed partial immunity.
Protective measures for crane populations or other wild birds currently consist only of the rapid reporting of sick and dead birds and the quick removal of carcasses by teams of experts in order to prevent further infections, especially among scavengers (crows, ravens, sea eagles, foxes). The public should avoid contact with sick or dead wild birds. Poultry farmers are strongly advised to implement strict biosecurity measures to minimize contact between poultry and wild birds and reduce the risk of HPAIV introduction.
