The use of su.crose-acetone-extracted Rift Valley fever virus antigen derived from cell culture in an indirect enzyme-linked immunosorbent assay and haemagglutination-inhibition

PAWESKA, J.T. , BARNARD, B.J.H. & WILLIAMS, R. 1995. The use of sucrose-acetone-extracted Rift Valley fever virus antigen derived from cell culture in an indirect enzyme-linked immunosorbent assay and haemagglutination-inhibition test. Onderstepoort Journal of Veterinary Research, 62:227-233 A sucrose-acetone-extracted , Madin-Darby-bovine-kidney (MDBK)-derived Rift Valley fever virus (RVFV) antigen was tested both in an indirect ELISA and a haemagglutination-inhibition test for its ability to detect serum antibodies to RVFV. Optimal conditions for antigen concentration , serum and conjugate dilutions for the ELISA were established by checkerboard titration . The specificity and sensitivity of ELISA were determined by the use of paired preand post-vaccination sheep-serum samples. Compared with the virus neutralization test, the overall ELISA specificity and sensitivity were 97,4 and 97,3 %, respectively. There was a 100% correlation between the results obtained in haemagglutination-inh ibition tests with a RVFV sucrose-acetone-extracted antigen derived from hamster liver, and from MDBK cells. A total of 10 582 field-serum samples (84 cattle, 3 659 sheep, 6 839 goats) collected in 1994-1995 from animals of unknown vaccination status in different regions of South Africa were tested with ELISA for antibodies against RVFV. There were no seropositive cattle, 0,16% seropositive sheep and 0,1 2% seropositive goats . This study demonstrates the potential diagnostic application of cell -culture-derived , sucrose-acetone-extracted RVFV antigen in an indirect ELISA and HI test.