A second case of swine fever was detected in Gifu Prefecture on Friday at a park, after the nation's first case in decades was reported in September at a nearby pig farm.
The Gifu Prefectural Government culled all 21 pigs kept at the Chikusan Center Park (Livestock Center Park) after confirming earlier in the morning through tests that two of them were infected with what is also known as hog cholera. The virus affects only pigs and wild boars, and has an almost 100 percent fatality rate.
Already 49 wild boars in the prefecture have been found to be infected with the virus, and two of them were found in the park in late September. But the pigs in the park had shown no signs of infection at that time, according to the prefecture.
The park said it will close until Nov. 25 due to disinfection and epidemic control work.
Farm minister Takamori Yoshikawa urged all prefectures to take measures to prevent wild boars from entering pig farms, deeming them to be the cause of the outbreak.
Eight Gifu pig farms near the affected park have been banned from shipping their pigs and meat outside the area.
Following the swine fever infection at a Gifu farm just 8 kilometers southeast of the park in September, Japan suspended exports of pork and related products from across the country.
But the ban on shipments had been lifted for some markets after individual negotiations, and Tokyo does not plan to stop exports to those destinations following the latest case, according to farm ministry officials.
Swine fever does not affect humans even if an infected animal is consumed. The nation's pork exports totaled around ¥1 billion ($9 million) last year.
Prior to this year's outbreak, Japan had only seen cases of swine fever in 1992 and had declared the virus eradicated in 2007.