反芻動物惡性卡他熱診斷技術之建立

Abstract

Malignant catarrhal fever (MCF) is a fatal viral disease of ruminants. There are four viruses to cause this disease. Ovine herpesvirus 2 is one of them to cause the worst danger. Because of the disease involved subclinical carriers with virus shedding and dead-end hosts, it is hard to eradicate via inspection and quarantine. Owing to false positive and false negative, CI-ELISA is usually to screen the herd for understanding the MCF infection, not for diagnosis. The nested PCR is the most common assay used for diagnosing MCF. It is highly sensitive and specific, but time consuming. A novel DNA amplification method, loop-mediated isothermal amplification (LAMP), can amplify DNA with high specificity and rapidity under isothermal conditions and can be employed in the field test. The aim of this study is to develop the LAMP method for diagnosing MCF and compare the results among CI-ELISA, LAMP and nested PCR. A total of 107 samples of archived paraffin samples and peripheral blood lymphocytes from MCF positive and unknown herds were obtained for this study. The result of the CI-ELISA, nested PCR and LAMP assays show positive rate of 67.5％, 37.5％ and 45％, respectively, in MCF-positive herds. The results were all negative by the established assay in nondetected herds. In conclusion, the LAMP method is about six times faster than the nested PCR in the diagnosis of MCF. It takes approximately one hour to obtain the results and has similar sensitivity with nested PCR. This technique provides highly potential for rapid and specific diagnosis of MCF.