An enzyme-linked immunosorbent assay for detection of antibodies to maedi-visna virus in sheep. II. Comparison to conventional agar gel immunodiffusion test.
A study was conducted to compare the indirect enzyme-linked immunosorbent-assay (i-ELISA) test using antigen prepared by a simple technique using sodium dodecyl sulfate (SDS) treatment to the conventional agar gel immunodiffusion test (AGID). Ten specific-pathogen-free (SPF) sheep were inoculated with maedi-visna virus (MVV) and serum antibody titers compared over a period of 14 weeks. All the sheep seroconverted by the i-ELISA compared to 90% by the AGID. The i-ELISA detected antibody at a mean of 2.6 weeks prior to the AGID. In both tests, fluctuations were observed in the serum antibody response of two sheep. The i-ELISA had a specificity of at least 98.8% and an increased relative sensitivity of 15.5% compared to the AGID, based on the analysis of sera from experimental sheep with MVV free status and sera from sheep from various sources. Of the sera from a seronegative flock which had been monitored with the AGID after a "test and remove" eradication program, 10.2% were positive by the i-ELISA. It was concluded that the AGID test may not be adequate to monitor samples for an eradication scheme.
Simard
C L
CL
Food Production and Inspection Branch, Agriculture Canada, Sackville, New Brunswick.
Briscoe
M R
MR
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood*; D000956:Antigens, Viral; D004797:Enzyme-Linked Immunosorbent Assay; D005779:Immunodiffusion; D011021:Pneumonia, Progressive Interstitial, of Sheep / Q000175:diagnosis*; D011237:Predictive Value of Tests; D012756:Sheep; D012967:Sodium Dodecyl Sulfate; D013047:Specific Pathogen-Free Organisms; D014790:Visna-maedi virus / Q000276:immunology*
D000914:Antibodies, Viral; D000956:Antigens, Viral; D012967:Sodium Dodecyl Sulfate