Field Validation of Laboratory Tests for Clinical Diagnosis of Sheep-Associated Malignant Catarrhal Fever

Abstract

Until recently, sheep-associated malignant catarrhal fever (SA-MCF) was diagnosed mainly on the basis of clinical presentation and histopathological changes. Using clinically diagnosed field cases, we have evaluated a seminested PCR and a competitive inhibition enzyme-linked immunosorbent assay (CI-ELISA) and compared these assays in the diagnosis of SA-MCF in cattle with histopathology as a provisional “gold standard.” Samples from 44 cattle with clinical signs suggestive of SA-MCF were examined by histopathology, PCR, and CI-ELISA. In addition, samples from healthy cattle were evaluated by PCR (n = 96) and CI-ELISA (n = 75). Based on histopathology, 38 of the 44 clinical cases were classified as SA-MCF positive, 3 were classified as inconclusive, and 3 were classified as SA-MCF negative. The sensitivity of PCR was 95 to 97%, whereas the specificity ranged between 94 and 100%. The CI-ELISA showed a sensitivity of 56 to 87% and a specificity between 91 and 100%. In the field, there is good correlation between the diagnoses of SA-MCF by histopathology, PCR, and CI-ELISA. These data also confirm the close association of ovine herpesvirus 2 with SA-MCF in Switzerland.

Molecular and Histopathological Characterization of Sheep-Associated Malignant Catarrhal Fever (SA-MCF) Outbreak in Beef Cattle

“…The hemi‐nested PCR used in this study is considered by many to be the best molecular PCR assay for the diagnosis of SA‐MCF in clinical samples (Li et al., ; Muller‐Doblies et al., ). Bovine blood samples were negative for the hemi‐nested PCR, indicating that the viraemia stage was not present at the time of sample collection, but ovine blood samples were still showing the viral DNA in the PCR.…”

Survey for the presence of White Spot Syndrome virus in Australian crustaceans

“…However, validated PCR tests routinely have specificities and sensitivities greater than 95% and usually in excess of 98%. 11,12 Although the specificity for the PCR test used was not known, the complete test regimen of retesting preliminary positive samples and the subsequent use of bioassay if required, was assumed to have an overall specificity of 100%. Based on the known sensitivity of other validated PCR tests, the sensitivity of the PCR testing regimen was assumed to be 95%.…”

Newly Recognized Herpesvirus Causing Malignant Catarrhal Fever in White-Tailed Deer ( Odocoileus virginianus )

“…This assay has become a useful epidemiological tool for studying MCF viral infection in a variety of ruminant species infected with viral strains that are heterogeneous at a base sequence level (9; H. Li, J. Keller, and T. B. Crawford, unpublished data). Development of PCR specific for the OHV-2 (2) or AHV-1 strains of MCF viruses has dramatically improved the accuracy of diagnosis of MCF in clinically infected animals (5,15). Furthermore, the PCR assay using degenerate primers targeting highly conserved amino acid motifs (32) within the herpesviral DNA-directed DNA polymerase gene (31) has become an important tool for the identification of new herpesviruses that cause clinical or subclinical infection in animals (20,24,26).…”