H5N1, commonly called bird flu, had been detected in cows. Scientists had been closely watching avian flu for years, worried about the potential jump to livestock. But their money was on pigs next.

Preliminary tests indicate a commercial chicken farm in Brazil's state of Tocantins is free from bird flu, the state's farm ...

The virus was discovered in a single animal on a farm in Yorkshire, in an area where highly pathogenic avian influenza H5N1 had been found in captive birds. The case appears to have been contained ...