The UK authorities are mulling new controls for pigs as well as poultry as the government and farmers prepare for a possible outbreak of so-called bird-flu. The move comes as scientists contemplate the role pigs might play in the transformation of avian flu.

Humans can be infected and killed by avian diseases, but human-to-human transmission is rare. Researchers suspect pigs can act as an interim step, transforming an avian virus into one that is highly contagious, and can spread easily between people.

Measures for controlling an outbreak of disease in poultry already exist: birds can be culled, or otherwise removed from the food chain if they are suspected of being infected. However, as bird-flu is not classed as a porcine disease, new powers would be needed to implement a similar culling of pigs.

The European Commission is to meet in Brussels tomorrow to discuss bird flu and other issues. It is introducing a directive that would enable governments to act in circumstances like these.

Pigs are thought to be at greater risk of exposure to the disease because of the increase in outdoor rearing and free range farming in the UK. Migrating birds may yet pose a threat to these pig populations.

However, the Department for the Environment, Food and Rural Affairs (Defra) said there was no need to bring free range poultry indoors, as the Dutch have done. ®