The European Commission adopted on Thursday a common European definition for swine flu as the novel flu virus.

This will allow for an amendment to the earlier decision, which lays down case definitions for reporting communicable diseases across the European Union, the Commission said in a statement.

"This case definition is a major step forward in setting common EU standards for diagnosing the novel flu virus," said Health Commissioner Androulla Vassiliou.

"It will enable more efficient compilation of comparable information on the novel flu virus at European level by ensuring that we are all talking about the same things. It will help us develop timely responses and drive forward our collective response to help protect the health of EU citizens," she said in the statement.

The European Center for Disease Prevention and Control (ECDC) provided, at the request of the Commission, a technical document which served as basis for the European case definition.

The Commission, EU's executive arm, has stepped up measures to monitor and prevent the spread of the flu.

"We have learned valuable lessons from past experiences with SARS and avian influenza. Not only are surveillance systems more robust today but we have also developed stronger collaboration mechanisms both at EU level and with our partners around the world," Vassiliou said.

The Commission raised its level of alert to "red" on April 27 by launching its Health Emergency Operating Facility (HEOF).

Vassiliou met on Wednesday with the pharmaceutical and vaccine industry in order to be briefed on the current state of play regarding antiviral and vaccines.

The ECDC said that the epidemiological situation is evolving quickly with 20 confirmed cases in the EU as the Netherlands announced one later Thursday. Ten are reported in Spain, five in Britain, three in Germany, and one in Austria.

All EU confirmed cases have a history of traveling to Mexico, except for one case in Spain where there is evidence of transmission within the household.

The novel flu virus (human swine influenza A/H1N1) has been found to contain genes from pig, bird and human influenza viruses, in a combination that has never been observed before anywhere in the world.

It spreads from person to person via droplets from an infected person who is coughing and sneezing. Symptoms of the virus in humans are usually similar to regular human seasonal influenza symptoms, involving fever of sudden onset and respiratory symptoms; diarrhoea might also occur, said the statement.