Bird flu has re-emerged in Indonesia’s main island of Java and South Sulawesi province since the start of the year, prompting the government to slaughter affected fowl, the agriculture ministry said on Thursday.

Sporadic outbreaks of bird flu in fowl have hit parts of the sprawling archipelago since the disease emerged in late 2003, with Java the worst hit, but authorities have insisted that overall the deadly disease is under control.

H.R. Wasito, director-general of animal husbandry at the ministry, said around 24,000 fowl died this month in South Sulawesi and more than 13,000 in West Java province in January.

He said the H5N1 strain, which can be deadly to humans, had been detected, but no cases had been reported in people.

“To prevent bird flu outbreaks from spreading, the government has ordered isolation and culling in the affected areas, and vaccinations in areas in a five kilometer distance,” Wasito said.

He said amore than a million doses of vaccine had been distributed. Inter-regional transportation, irregular vaccinations and porous borders may have caused the disease to spread, he added.

The Indonesian government has said bird flu is endemic and that it would take years to fully stamp out the H5N1 strain that has swept large parts of Asia since late 2003.

The H5N1 strain can jump from birds to humans and can be deadly. It has killed 34 Vietnamese, 12 Thais and one Cambodian.