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| Gifu Prefecture - Credit Wikipedia |
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Six days ago, in Japan: MAFF Confirms Classical Swine Fever Outbreak, we saw the first detection of CSF in Japan in 26 years. Japan was just one of 35 countries (see map below) that have been certified by the OIE as being free of the disease, a status they no longer enjoy (see OIE Statement).
Today a post by Shiloh on FluTrackers of an article in the Japan Times led me to a press release from Japan's NARO (National Agriculture and Food Research Organization) that describes this outbreak as stemming from a Subgenotype (2.1) not previously seen in Japan.
The newspaper article also reports the discovery of a dead wild boar, found 8 km from the affected farm that has also tested positive, raising concerns the virus is spreading in that population.African Swine Fever (for which no vaccine is available) is arguably harder to control than CSF, but both pose a serious threat to any nation's pork industry.
The (translated) press release from NARO suggests this new-to-Japan genotype may have an Asian or European origin.
Press release
(Research Results) Analysis of the nucleotide sequence of swine fever virus detected in Gifu prefecture
Information release date: Friday, September 14, 2018
point
The National Agricultural Research Institute Animal Health Research Division analyzed the nucleotide sequence of the causative virus of swine fever that occurred in Gifu Prefecture for the first time in 26 years, and as a result, it was found that the virus was highly likely to invade from overseas It was. We will continue to analyze the virus in detail in the future.
Overview
The Hog Cholera Virus is divided into three groups (Genotype) according to the gene sequence of a specific region of the viral gene, and further subdivided into subgroups (Subgenotype).
Viruses detected from infected pigs confirmed in Gifu Prefecture on 9th September 2018 belonged to the Subgenotype 2.1 group from the verification with the hog cholera virus registered in the international database of nucleotide sequence data It was.
In addition, (1) that many vaccine strains, including vaccine strains used in Japan, belong to the group of genotype 1, (2) viruses belonging to the group of Subgenotype 2.1 have not been detected in Japan, and (3) viruses belonging to Subgenotype 2.1 , As it was detected in Europe and Asia, it seemed likely that the virus had invaded from overseas.
From now on, we will conduct detailed analysis of antigenicity and pathogenicity including infection test for the virus.
Explanation of terms
1) Hog cholera
It is a legal infectious disease of swine and fowl due to infection with Hog Cholera Virus, characterized by high mortality rate and strong infectivity.
2) gene phylogenetic tree
It shows the genetic relation of living organisms in a line, using amino acid sequence and DNA base sequence as data. A diagram like a branching tree is obtained, and in the case of closeness, it is shown on a nearby branch.
