BLUETONGUE VIRUS DETECTION - A SAFER REVERSE-TRANSCRIPTASE POLYMERASECHAIN-REACTION FOR PREDICTION OF VIREMIA IN SHEEP

A reversible target capture viral RNA extraction procedure was combine d with a reverse-transcriptase nested polymerase chain reaction (PCR) to develop a capture PCR assay providing a rapid and safe prediction m ethod for circulating bluetongue virus in infected ruminants. This new assay was compared with virus isolation and a recently developed anti gen-capture enzyme-linked immunosorbent assay (ELISA) for the detectio n of bluetongue virus. Eight Warhill crossbred sheep were inoculated s ubcutaneously with bluetongue virus serotype 10, and blood samples wer e taken sequentially over a period of 28 days. The capture PCR detecte d the peak of viremia, as determined by virus isolation and antigen-ca pture ELISA, from day 5 to day 14 after challenge. The results indicat e that the rapid-capture bluetongue virus PCR provides a rapid indicat or of samples in which virus can be isolated. In addition, this captur e bluetongue virus PCR procedure does not require a lengthy phenol ext raction or the use of the highly toxic methyl mercury hydroxide denatu rant.