The government confirmed on Monday that avian influenza was the cause of wild bird deaths in North Jeolla Province, fueling concerns of a nationwide outbreak.

On Friday, a large number of Baikal teals were found dead in a reservoir between Gochang-gun and Buan-gun in North Jeolla Province, where bird flu broke out on duck farms last week.

“It was verified as H5N8 but whether it is highly pathogenic will be confirmed later in the day,” said the Ministry of Agriculture, Food and Rural Affairs.

The strain is likely to be the highly pathogenic one, it added.

Earlier last week, the outbreak of the highly pathogenic H5N8 bird flu was detected at three local farms located some 300 kilometers south of Seoul, leading to a cull of more than 130,000 birds.

The investigation is still ongoing but migratory birds’ excrement is suspected to be the source of the contagion, officials said.

The government issued a temporary standstill on the poultry industry in the Jeolla provinces at midnight Sunday to restrict the movement of poultry, industry workers and equipment for 48 hours. The temporary lockdown will not be extended, the government added.

Currently, over 8.8 million poultry are raised in Gochang-gun, Buan-gun and Gunsan, North Jeolla Province.

A local news outlet reported Monday that three additional poultry farms in the region are suspected to be infected with bird flu. The quarantine authorities decided to slaughter some 40,000 ducks as a preventive measure. According to the report, samples from the farms were taken in for testing, the results of which will become available later in the day.

As the outbreak unfolds, the authorities are stepping up preventive measures and monitoring of migratory birds, considering the three-week incubation period of the deadly animal virus.

This is the first time the highly pathogenic H5N8 strain has broken out in South Korea. The strain has never been known to infect humans, the Ministry of Health and Welfare said.

This is the first case of bird flu detected since May 2011, when over 3 million poultry had to be culled. South Korea was threatened by bird flu four times in the past. Since 2006, more than 20 confirmed cases of bird flu have occurred in North Jeolla Province, causing about 110 billion won ($103 million) in losses.

By Lee Hyun-jeong (rene@heraldcorp.com)