The use of an indirect ELISA with protein G-peroxidase conjugate and a blocking ELISA to demonstrate recent bluetongue infection in sheep.
The humoral immune response of sheep infected with bluetongue virus serotypes 3, 9 and 16 was monitored by plaque inhibition (PI), blocking ELISA (BELISA) and indirect ELISA over a period of 63 days post-infection. Results indicated that testing of a single plasma or serum sample by both a BELISA and an indirect ELISA using a recombinant streptococcal protein G (PrG) peroxidase conjugate enabled an assessment of the proximity of a recent infection based on the failure of PrG to bind ovine IgM class antibodies. When BELISA and indirect ELISA results were expressed as a ratio, values indicative of recent infection (> or = 5) were observed for an average duration of 16.5 days (range 8 to 23 days) following the initial detection of antibody by BELISA. This approach has potential to improve diagnosis of a wide range of virus infections by providing an indicator for the relationship of serological status with a recent infection. However, where reinfection may occur, as with bluetongue virus, alternative methods may be required for definitive diagnosis.
Lunt
R A
RA
CSIRO Australian Animal Health Laboratory, Institute of Animal Production and Processing, Geelong.
Blacksell
S D
SD
Newberry
K M
KM
D000818:Animals; D000914:Antibodies, Viral / Q000096:biosynthesis / Q000097:blood*; D001819:Bluetongue / Q000097:blood / Q000175:diagnosis* / Q000276:immunology; D001820:Bluetongue virus / Q000145:classification / Q000276:immunology*; D003289:Convalescence; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D008297:Male; D012703:Serotyping; D012756:Sheep / Q000276:immunology; D013997:Time Factors
D000914:Antibodies, Viral