Pigs at a farm in Saitama Prefecture have been infected with the swine fever virus, the agriculture ministry has said, as authorities continue to struggle to contain the highly contagious disease one year since it first emerged.

The case reported Friday in the Kanto region was the first there since the epidemic began in Gifu Prefecture in September last year.

A pig raised by a farm in Chichibu, Saitama Prefecture, died after being shipped Wednesday to a meat-processing plant in neighboring Yamanashi Prefecture with 36 other animals. Another three pigs were also found to have internal organ problems, according to the Ministry of Agriculture, Forestry and Fisheries.

The Saitama Prefectural Government began culling around 680 pigs at the farm after about 20 tested positive for infection.

The disease affects only pigs and wild boars, and has a high fatality rate. It does not affect humans even if meat from an infected animal is consumed.

Infected wild boars, suspected of spreading the virus, have been found in Gifu and several other prefectures.

The outbreak is the first in Japan since 1992. The country declared the virus eradicated in 2007.

Following the case reported in Gifu, infections have also been confirmed in Aichi, Mie and Fukui prefectures.