The agriculture ministry said in a statement this week that it had decided to order the culling of the ducks after antibodies showed up which could indicate the birds were in contact with the contagious virus. A follow-up test has not confirmed an outbreak of bird flu but a further test was not able to rule out a mild strain of the virus.
On Saturday, the government decided to cull all 22,000 chickens at a farm in Eemsmond in the northeast of the country as a precautionary step after blood samples taken there also indicated birds had developed antibodies to the virus. Two neighbouring poultry farms, as well as a third company, were still under investigation, although preliminary tests were all negative.
Reuters reports that the results of further tests will only be available in 10 to 14 days.
The Dutch are determined to ensure that the virus does not return. Last year a mild form of the virus mutated into an aggressive variant, leading to the slaughter of a quarter of all Dutch poultry at a cost of hundreds of millions of euros. Some 30.7 million birds in total had to be slaughtered.
Europe as a whole is still at heightened alert following the recent bird flu epidemic that devastated parts of Asia. Last month, the European Parliament voted to create a European Centre for Disease Prevention and Control (ECDC), following growing public concern over animal disease epidemics.
"Outbreaks like SARS in 2003 and bird flu this year have been a wake-up call," said David Byrne, the European Commissioner for health and consumer protection.
The formation of the ECDC can be seen as part of a larger trend towards consolidated action in identifying and fighting animal-borne diseases. The world's largest online database of information on how pathogenic bacteria respond to different environmental conditions in food was established recently by scientists with the USDA's Agricultural Research Service and the UK's Institute of Food Research.
The database, called ComBase, is designed to help make risk assessments and model development easier.