Photo/IllutrationWorkers are seen in protective gear at a farm where the outbreak of hog cholera was confirmed in Uruma, Okinawa Prefecture, on Jan. 8. (Kazutaka Eguchi)

  • Photo/Illustraion
  • Photo/Illustraion

URUMA, Okinawa Prefecture--A mass culling of pigs is under way at three farms here, as authorities rush to contain the first outbreak of hog cholera in the prefecture since 1986.

Authorities expressed concern over the problem, as it indicates the disease, which has already affected nine other prefectures, has spread from the main island.

About 390 members of the Ground Self-Defense Force were dispatched to the prefecture at the request of prefectural officials to help handle the destruction of the 825 hogs at the pig farms operated by two farmers in the city. An additional 988 at a nearby farm will also be destroyed due to suspected infection, bringing the total to 1,813.

The operation by the central and prefectural governments started Jan. 8 and is expected to be completed by Jan. 11.

Cases of classical swine fever (CSF), or hog cholera, have not been confirmed at other farms in the prefecture as of the evening of the day the culling started.

The hogs to be destroyed included the relatively small, black-haired Agu breed that is native to the prefecture and went nearly extinct at one time before being crossbred to produce a new breed.

Meat from the animal is an important part of the cuisine in Okinawa, where more than 200,000 pigs are being raised by farmers.

Agriculture Minister Taku Eto, who was visiting the prefectural capital of Naha to explain the anti-CSF measures to Okinawa Governor Denny Tamaki on Jan. 8, expressed a sense of alarm to the media following confirmation of the outbreak.

"The infection in Okinawa Prefecture, which is far and separated from the main islands of Japan by the sea, is a serious problem," he said.

The first outbreak of hog cholera on the main island of Honshu was reported in Gifu Prefecture in September 2018, the first time in 26 years in Japan. Since then, it has spread to eight other prefectures, including in the Kinki and Kanto regions.

However, no infection had been confirmed in Kyushu until the recent deaths of hogs in Uruma.

The pig farmers in the city continued shipping the animals even though about 50 had died between Dec. 20 and Jan. 6, according to officials at the animal husbandry section of the Okinawa prefectural government. Twenty-five hogs were shipped by the farmers on Dec. 26.

"I'm very concerned about the future," said one hog farmer yet to be affected in Uruma.

Prefectural officials said they were alerted to the deaths of the pigs in Uruma on Jan. 6, adding that the farmers had given the pigs feed, such as meat, without heating it first. As a result, the hog cholera virus likely remained active, according to experts.

The officials ruled out the possibility of infection from overseas sources, citing results of a gene analysis of the pigs infected with the disease.

The viruses found in the dead pigs showed a similar CSF gene type found elsewhere in Japan. The farmers in question said they had not been in other countries.

While humans cannot be affected by the disease, pigs and wild boars develop a fever after being infected and are highly likely to die.

As part of the efforts to contain the spread of the virus, the prefectural government restricted the movement of pigs and other animals in a 3-kilometer radius of the affected farms.

Shipments will be prohibited inside a 10-km radius, where about 50 farmers operate.

(This article was written by Kazuyuki Ito, Shinichi Fujiwara and Shinya Maeda.)