Belgium has reported its first confirmed case of avian influenza, which has evaded controls and spread from the Netherlands to a farm in the eastern border region of Limburg.

“We found a few hundred dead chickens on a farm yesterday,” Guy Timmerman, a spokesman for Belgium’s food safety agency, told Reuters. “Samples were taken and the results came out positive [for avian flu] last night.”

Timmerman said that health authorities planned to slaughter all poultry within a three-kilometre radius of the infected farm, as well as suspending the transport of all poultry and poultry products.

The Netherlands has been trying to control the highly contagious disease since it first broke out in the country at the end of February. Although not harmful to humans, this strain of the disease is fatal to poultry.

The Netherlands has slaughtered around 11 million birds since the outbreak began, but is still discovering new cases. Germany has ordered poultry to be slaughtered on several farms near the Dutch border as it tries to prevent the spread of the disease.