Defying the dire predictions of health officials, the flocks of migratory birds that flew south to Africa last fall, then back over Europe in recent weeks, did not carry the deadly bird flu virus or spread it during their annual journey, scientists have concluded.
International health officials had feared that the disease was likely to spread to Africa during the southward migration and return to Europe with a vengeance during the reverse migration this spring. That has not happened – a significant finding for Europe, because it is far easier to monitor a virus that exists domestically on farms but not in the wild.
“It is quiet now in terms of cases, which is contrary to what many people had expected,” said Ward Hagemeijer, a bird flu specialist with Wetlands International, an environmental group based in the Netherlands that studies migratory birds.
In thousands of samples collected in Africa this winter, the bird flu virus, H5N1, was not detected in a single wild bird, health officials and scientists said. In Europe, only a few cases have been detected in wild birds since April 1, at the height of the migration north.
The number of cases in Europe has fallen off so steeply compared with February, when dozens of new cases were found daily, that specialists contend the northward spring migration played no role. The flu was found in one grebe in Denmark on April 28 — the last case discovered — and a falcon in Germany and a few swans in France, said the Paris based World Organization for Animal Health.
In response to the good news, agriculture officials in many European countries are lifting restrictions designed to protect valuable poultry from infected wild birds.