Field validation of laboratory tests for clinical diagnosis of sheep-associated malignant catarrhal fever.
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.
Müller-Doblies
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UU
Institute of Virology, University of Zürich, Zürich, Switzerland.
Li
H
H
Hauser
B
B
Adler
H
H
Ackermann
M
M
D000818:Animals; D001921:Brain / Q000473:pathology; D002417:Cattle; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D008304:Malignant Catarrh / Q000175:diagnosis* / Q000473:pathology; D016133:Polymerase Chain Reaction / Q000379:methods; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012756:Sheep