CSF Japan: Outbreak flares up, disease-free status lost

It has been relatively quiet with outbreaks of Classical Swine Fever (CSF) on farms in Japan for the last 6 months, yet the disease returned to domestic pigs in recent weeks. In the meantime, the country officially lost its CSF-free status.

The latest outbreak of Classical Swine Fever was discovered on September 25 in Takasaki City, Gunma prefecture, located north west of Tokyo. It was the first case in this prefecture. Infected wild boar have been discovered in the prefecture since September 2019, which was followed by vaccinations for farmed pigs in October 2019. The animals at the farm in the recent outbreak, however, were all piglets which had yet to be vaccinated.

All pigs to be culled and buried

The piglets on the farm started dying in early September after suffering from diarrhoea. This resulted in a total of 200 deaths, according to the Gunma prefecture’s authorities. At a press conference on 27 September 2020, governor Ichita Yamamoto announced that regardless of vaccination, all pigs on the farm were to be culled and buried on private land near the farm owned by the farmer.

Yamamoto added that at the time of the incident, the farm housed about 5,390 pigs. There are no farms within 3 km of the affected farm.

No longer CSF-free

The outbreak virtually coincided with the news that Japan officially lost its CSF-free status, on September 3^rd of this year. Japan had already been suspended for 2 years by the World Organization for Animal Health (OIE).

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The loss is a direct result of the country’s failure to contain an outbreak that started 2 years ago in September 2018, when finishing pigs were found dead in Gifu prefecture. Although the Japanese Ministry of Agriculture, Forestry and Fisheries (MAFF) initially responded to the outbreak by culling pigs, wild boar carried the disease to other areas, mainly to central and eastern Japan. From then onwards, CSF was confirmed at pig farms in 10 prefectures, including but not limited to Nagano, Saitama and Aichi.

Over 160,000 pigs culled

In total, according to the Japan Times, 166,000 pigs have been culled so far to contain the spread of the virus. To regain its CSF-free status, Japan will have to make sure that no cases are reported and no vaccinations for the disease are carried out for a 12-month period.