Kuala Lumpur: Bird flu outbreaks in northern Malaysia have not infected any swiftlets, the birds whose nests are used in the costly Chinese delicacy bird's nest soup, officials said yesterday.

Ethnic Chinese entrepreneurs in the states of Penang and Perak, where the deadly H5N1 strain was found in poultry and wild birds earlier this month, operate thousands of huge barns inhabited by swiftlets that laboriously weave their cup-shaped nests from glutinous saliva.

But so far, veterinary tests show the disease hasn't spread to the sparrow-like swiftlets, said Chang Ko Youn, the head of Perak's government urban and planning board.

"We're having regular inspections to test swiftlet droppings," Chang said.

Airborne insects

This month, authorities confirmed H5N1 in birds in several villages in Perak and Penang, mainly in chickens and wild birds, spurring officials to slaughter more than 50,000 fowls to stop the disease from spreading.

But the swiftlet colonies face little danger because the birds keep to themselves, consume only airborne insects and rarely land on the ground, preferring to remain on trees or structures that suit their needs, Chang said.

Also, the recent outbreaks occurred far from swiftlet hubs. In Penang, the villages hit were 60km from nest production centres, said state legislator Tan Cheng Lian.

Officials slaughter all birds within a kilometre of any bird discovered with H5N1, so nest businesses could be jeopardised if the disease strikes other birds nearby.