JAKARTA (Reuters) – An outbreak of African swine fever in Indonesia’s North Sumatra province has been detected by laboratory tests carried out after the deaths of thousands of pigs in the area this week, an agriculture ministry official said on Friday.

A provincial official said on Wednesday that more than 4,000 pigs had died after an outbreak of classical swine fever, also known as hog cholera.

“Clinical symptoms and laboratory test results point to African swine fever, but there are also samples that are positive for hog cholera,” Fadjar Sumping Tjatur Rassa, the agriculture ministry’s director of animal health, told Reuters.

Classical swine fever was first detected in September in the province’s Dairi district, a local official said.

Rassa could not say how many of the pigs deaths may have been caused by an outbreak of African swine fever (ASF).

“For the ASF, of concern is the economic loss because of its rapid spread and its high mortality rate,” Rassa said, adding that both classical swine flu and ASF did not infect humans.

He said the government had implemented bio-security measures in the affected areas by ordering authorities to immediately bury pig carcasses and disinfect areas to prevent the virus spreading.

Pigs and pork products from affected the area could not be transported to other places, he said.

Video footage showed officials from authorities in North Sumatra collecting pig carcasses that had been thrown into rivers this week by boat in order to bury them.

East Timor, which shares an island with Indonesia’s East Nusa Tenggara province, reported in September that there were 100 outbreaks of ASF, killing 405 backyard pigs.

(Reporting by Bernadette Christina Munthe; Writing by Fransiska Nangoy; Editing by Edmund Blair)