A genetic probe for identifying bluetongue virus infections in vivo and in vitro.

We have used a DNA copy of segment 3 RNA of bluetongue virus serotype 17 (BTV-17) to detect sequence homology among the equivalent segments of five U.S.A. BTV serotypes (BTV-2, BTV-10, BTV-11, BTV-13 and BTV-17) as well as 14 other BTVs isolated from different endemic areas of the world. Both by in situ and Northern hybridization all the BTV serotypes were found to have RNA that reacted with the DNA probe. No homology was detected with epizootic haemorrhagic disease virus serotype 1, a related orbivirus. The BTV-17 DNA clone has also been used to detect viral RNA in infected sheep blood. This information has led us to develop a simple and sensitive procedure for the detection of viral genome-biotinylated clone DNA hybrids in vivo or in cultured cells following direct staining with either the avidin-fluorescein complex or the streptavidin-horseradish peroxidase complex.