The National Agriculture and Food Research Organization (NARO) and Nippon Gene Co., Ltd., have developed two types of molecular-based testing kits, 'Johne-Find' and 'Johne-FindPRO', as new diagnostic tests for Johne's disease, a disease that primarily affects cattle. Screening tests using 'Johne-Find' can detect infected cattle more than six months earlier than current testing methods. 'Johne-FindPRO' has high specificity and allows accurate diagnosis in confirmatory testing. The combination of these two tests enables early detection of infected cattle with high diagnostic accuracy and facilitates the disease control in Japan.
Overview
Johne's disease is a bacterial infection in ruminants characterized by chronic diarrhea. It is designated as a Domestic Animal Infectious Disease under Act on the Prevention of Infectious Diseases in Livestock. Vaccination or treatment is not considered as a practical option, and therefore current disease control strategies in Japan are mainly based on test-based culling of infected animals. However, outbreaks are still being confirmed across the country, and approximately 1,000 cattle are diagnosed and slaughtered annually. Most infected cattle show no clinical signs for an extended period of time, yet they may shed small numbers of bacteria in their feces. Although early detection of infected cattle is important for breaking transmission within a herd, it is often challenging to detect sub clinically infected animals with the current diagnostic tests, resulting in prolonged control measures.
NARO, in collaboration with Nippon Gene Co., Ltd. have developed two new real-time PCR-based diagnostic test kits for Johne's disease, with the aim of early detection of infected cattle and improved diagnostic accuracy. The 'Johne-Find' kit detects paratuberculosis DNA in feces and is used for the screening of whole herds. It enables to detect infected cattle more than six months earlier than the current screening method, i.e., antibody ELISA test. 'Johne-FindPRO' is used for confirmatory tests to diagnose whether cattle that have tested positive in screening tests are really infected or not. 'Johne-FindPRO' is a quantitative real-time PCR-based test kit using specific hybridization probes, which improves diagnostic specificity and accuracy.
'Johne-Find' and 'Johne-FindPRO' are approved as veterinary in-vitro diagnostic products by National Veterinary Assay Laboratory. In the future, it is expected to be used nationwide as official diagnostic tests for Johne's disease. Both kits will be released by Nippon Gene Co., Ltd. on November 28th.
Reference
Journal of Clinical Microbiology 58(12):e01761-20 (2020) doi: 10.1128/JCM.01761-20
