Indonesian health officials say 13 people suspected of having bird flu have tested negative for the deadly disease.

Officials in Asahan district in North Sumatra province said villagers began showing symptoms of avian flu after a large number of chickens died suddenly last week in Air Batu village.

Tests run on the chickens showed they died from the lethal H5N1 strain of avian flu.  

More than 240 people around the world have died since an outbreak of the H5N1 strain was first detected in poultry stocks across Asia in 2003.  Indonesia has recorded 111 deaths from the virus, the highest of any nation.  

Humans can contract avian flu only from direct contact from infected poultry.

Experts fear the virus will mutate into a form easily passed between humans, which  could lead to a pandemic that could kill millions of people.

Some information for this report was provided by AFP and Reuters.