Four people who were tested for suspected bird flu after developing fever in a northern Malaysian state have been found to be free of the disease, an official said today.

"All four are found to be negative. The have not contracted the H5N1 disease," Health Ministry disease control department director Ramlee Rahmat told AFP.

One of those tested was a 43-year-old chicken breeder who lives a kilometre from an outbreak among birds in Changkat Tualang village, and another was his seven-year-old neighbour.

The other two live about 10 kilometres from the Laketown Resort nature reserve where the disease has also been discovered in birds.

Ramlee said no new suspected cases have been reported in the past 24 hours but health officials were making a door-to-door check of people living within 300 metres (990 feet) of the two outbreaks.

Thousands slaughtered

Veterinary officials have slaughtered tens of thousands of birds at both sites since the outbreaks were discovered on Thursday.

A veterinary official in Perak state said the slaughter of poultry was almost complete with 42,399 birds killed so far. The state has one of the country's biggest poultry industries and exports to neighbouring Singapore.

H5N1 was detected last month in 40 free-range chickens in four villages on the outskirts of Kuala Lumpur, the first outbreak in the country in more than a year.

About 100 people have died from bird flu in eight countries mostly in Asia since 2003. So far, there have been no human deaths in Malaysia.