The European Union has extended its measures to fight avian influenza in Belgium and the Netherlands.

The EU’s ban on exports of live poultry and hatching eggs from the two countries will now remain in place until after EU veterinary experts meet to review the restrictions on 15 May. The current restrictions had been due to expire on 12 May, reported Reuters.

Belgium has confirmed a total of eight cases of bird flu but has registered no new cases since 24 April. The country has eased restrictions on the movement of poultry within Belgium, allowing farmers to move one-day-old chicks and hatching eggs outside the surveillance zones.

The Netherlands has reported no new cases since last week, when only two were discovered.

“We’re hopeful, but we’re not optimistic yet,” the Netherlands’ Agriculture Ministry spokeswoman Martine de Haan was quoted by Reuters as saying.

The Netherlands has been hit hard by the disease. Since the outbreak began, 250 cases of bird flu have been discovered in the country, leading to the slaughter of 25 million birds, a quarter of the country’s poultry population.

The government has estimated that spending on controlling the outbreak and on compensation to farmers totalled €211m up to 23 April, De Haan said. Commercial losses are believed to exceed €100m.

The Netherlands is the world’s fourth biggest poultry exporter and its largest egg exporter.