Origin of recent H5N1 outbreaks in Europe remains unclear
This weekend, there were several infections in 'new' wild birds confirmed in Europe. In Germany, infected seagulls and a goshawk were found. In France the ‘dangerous’ birdflu virus H5N1 has been reported in a wild duck, apparently a Pochard (Aythya ferina). The Pochard was confirmed as having died near Lyon on 19 February.
Until now most cases in Europe related Mute Swans, but the confirmation of this case in a duck complicates interpretation of possible sources of H5N1 outbreaks in Europe.
Pochards infected with H5N1 have already been found in small numbers Iran over the last weeks. The migration of infected Pochards from Iran to France is unlikely. The Iranian Pochards are most likely to originate and return to Central Asia.
Migration of the Pochard
A small part of the population in Western and Southern Europe, including France, is present throughout the year, There are, generally speaking, two overlapping wintering populations of the Pochard in France: one with birds coming from Eastern Europe and Siberia. Another population is wintering in the Mediterranean and comes from southern Siberia and Russia. Small numbers of Pochards winter in the Sahel zone of West Africa, in the Nile Valley and in East Africa.
Explanation of the outbreak
Explanations of all these outbreaks remain speculative. The remote possibility exists that an early migrating bird from this tiny West African wintering population of Pochards transported the disease from Nigerian outbreak areas to France. It also seems possible that exceptionally cold weather in Eastern Europe in January and February may have disrupted normal patterns of migration this year and caused movements of wild birds from outbreak areas around the Black Sea. There is still no way of knowing if these scenarios are possible, and any of the outbreaks could also have originated from activities in the poultry rearing and transport industries.
Programme manager avian influenza
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Wetlands International is a global organisation that monitors the migration of millions of waterbirds annually. At this moment, the organisation conducts several programmes fro the EU and FAO to understand the possible spread of the avian flu among wild birds.