Photo/IllutrationSaitama prefectural government workers incinerate culled hogs infected with swine cholera. (Provided by Saitama prefectural government)

The farm ministry will begin vaccinating hogs against swine cholera in areas where infections have been confirmed for the first time in two decades.

A formal announcement about the start of vaccinations was made on Sept. 20 and would be limited to prefectures based on discussions among experts in an advisory panel.

That will likely mean a certain period of time will be required before the vaccinations actually begin.

The first confirmation was made more than a year ago at a hog farm in Gifu Prefecture, which marked Japan's first swine cholera case in 26 years.

Subsequent infections were found in Aichi, Mie and Fukui prefectures. Earlier this month, a hog farm in Saitama Prefecture reported the first swine cholera infection in the Kanto region.

Vaccinating hogs poses a risk to exports because under international rules farms that use the vaccines are considered as unsanitary.

Farm ministry officials are hoping to avoid negatively impacting the industry as a whole by only vaccinating hogs in areas affected by the disease.

There is enough vaccine in Japan for about 1 million hogs. Ministry officials will also ask manufacturers to produce more vaccine.

But mass vaccinating hogs would not allow for differentiating between animals that have developed immunity to the disease and those that have been infected. Doing so could also delay discovery of new swine cholera cases.

To prevent the spread of the disease, farm ministry officials plan to limit distribution of vaccinated hogs and products made from them to the area where they were vaccinated.

Local government officials, however, have raised doubts over the effectiveness of their plan.

(This article was written by Hirobumi Ohinata and Noriyuki Kaneta.)