National Agriculture and Food Research Organization (NARO) and Takara Bio Inc. have jointly developed a brand-new real-time PCR method to distinguish between field and vaccine strains of classical swine fever virus (CSFV). This method allows quick determination of whether a wild boar tested to be "CSFV positive" during surveillance was infected by a virulent field strain or orally immunized with a bait-type vaccine strain. In areas where CSF is prevalent and bait-type vaccination is applied, this method will also be useful for monitoring the status of virus circulation and evaluating the effectiveness of bait vaccination of wild boars.
Overview
Currently to prevent the spread of CSF in Japan, bait-type oral vaccines containing live attenuated CSFV are used to confer immunity against the disease in wild boars. Presently, when a wild boar testing positive for CSFV is found within areas where the oral vaccines are distributed, test samples are sent to the NARO for confirmatory diagnosis for CSF. Nucleic acid sequencing analysis is carried out to determine whether the wild boar was infected with a field strain or immunized with the vaccine strain after uptake of the bait-type vaccine. However, this analysis takes time to distinguish between the two and requires complicated and costly procedures, so it is not practical.
NARO and Takara Bio Co., Ltd. collaborated to develop a new real-time PCR test method that allows for easy and quick differentiation of prevalent field strains and oral vaccine strains of CSFV and developed a series of test reagents suitable for this identification test. This test method uses reagents similar to the "Swine Fever Virus/African Swine Fever Virus Detection Reagents", released in November 2021. Therefore, it is possible to prepare test samples with rapid and simple pretreatment. The treated "CSFV positive" samples can be continuously subjected to this test without preparing new samples, so it is possible to determine accurately whether the virus is a field strain or a vaccine strain.
By using this rapid and accurate test method, it is possible to quickly respond to new field cases of wild boar with preventive measures or accurately assess the effectiveness of oral vaccinations in the target areas.
This new test method can be used by national and prefectural disease diagnosis laboratories within the framework of "Specific Domestic Animal Infectious Disease Quarantine Guidelines for Swine Fever" to "Distinguish Field Strains and Vaccine Strains in Swine Fever Tests of Wild Boars" (Notification No. 6955 of the Animal Health Division Manager dated March 31, 2022) (Revised September 26, 2022). A series of test reagents applicable to this method is released by Takara Bio Inc. on March 22, 2023.
For Inquiries
Contact: http://www.naro.go.jp/english/inquiry/index.html
