Japan mulls classical swine fever vaccination strategy

While Japanese farmers urge their government to begin a program to vaccinate domestic pigs against classical swine fever (CSF), this strategy is set to start in selected areas for wild boar.

RGtimeline | iStockPhoto.com
RGtimeline | iStockPhoto.com

While Japanese farmers urge their government to begin a program to vaccinate domestic pigs against classical swine fever (CSF), this strategy is set to start in selected areas for wild boar.

After an absence of 26 years, CSF returned to Japan in September 2018. The majority of early outbreaks were in the wild boar populations of Gifu and Aichi prefectures in central Honshu, but the number of cases among domestic pigs has increased sharply in the past month, and the virus has also been detected in Nagano, Osaka and Shiga.

In order to protect their herds, pig farmers are now calling on the government to allow vaccination, reports Japan Times.

Urging the agriculture minister, Takamori Yoshikawa, to permit the use of CSF vaccines, head of the pig farmers association of Shizuoka prefecture, Katsumi Nakajima, said producers in the area would never recover if their animals became infected and had to be culled. So far, the CSF virus has not been detected in Shizuoka, but several pig herds have been affected in neighboring Aichi.

Officials warned that any vaccination program would have to be applied to all pigs in the designated area, and that pork sales could be hit by negative perceptions for some time afterwards. Furthermore, some countries would stop imports of Japanese pork because the country would lose its status as CSF free. It took 11 years for Japan to regain this status after the government ended its previous policy of allowing vaccination in 1996.

New outbreaks

Since our last report two weeks ago, two new outbreaks of CSF in domestic pigs have been confirmed by the Japanese agriculture ministry to the World Organisation for Animal Health (OIE). These bring the official outbreak count to 10.

On February 12, a farm in Tahara in Aichi prefecture was inspected because of its link to a previous outbreak in the area. After a number of CSF virus-positive cases were identified, the herd of 1,180 animals was culled. More than 13,400 pigs were destroyed the next day at a neighboring facility that shared vehicles, offices and slurry storage.

The 10th CSF outbreak was confirmed at a farm in Mizunami in Gifu prefecture the next week. Several animals were observed to have a reduced appetite and fever. Presence of the CSF virus was confirmed as three pigs died and the rest of the herd of 5,772 was culled to try to prevent the further spread of the disease.

Based on official reports to the OIE, CSF has directly affected 16 pig farms in Japan, and almost 47,500 animals have been lost to the disease through mortality or culling since September 2018.

Government initiates CSF vaccination in wild boar

Citing the escalating number of cases in wild boar, the Ministry of Agriculture Food and Fisheries announced last week it is introducing a CSF vaccination scheme for wild boar in the worst-affected prefectures of Gifu and Aichi.

So far in February, there have been at least 52 confirmed cases of the disease in wild boar, according to the latest reports from the agriculture ministry to the OIE. All these cases were in Gifu.

Of the 795 wild boar tested in Gifu, 170 have tested positive for the CSF virus since September 2018, and 10 of the 59 tested in Aichi were infected, according to the latest official report to the OIE. The virus has not been detected in any of the 210 animals sampled in 39 other prefectures.

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