Washington has stepped up its avian flu screening programme to protect the USA from what it sees as the “increasingly likely” arrival of the H5N1 strain of the disease.

“By intensifying our monitoring of migratory bird populations, we increase the likelihood of early detection, which is key to controlling the spread of the virus in our domestic poultry,” said agriculture secretary Mike Johanns.

Testing migrating birds for H5N1 has been ongoing in the USA since 1998, he told journalists this week.

But given the recent global expansion of the disease and the onset of the spring migration, the time had come to increase the level of screening.

In 2006 the US department of agriculture will collect up to 100,000 live and dead wild birds and a further 50,000 samples of faeces.