SINGLE RADIAL HEMOLYSIS TECHNIQUE APPLIED TO MEASUREMENT OF ANTIBODIES TO CHILEAN STRAINS A EQUI/1/SANTIAGO-77 (H7N7) AND A/EQUI/2/SANTIAGO-85 (H3N8) OF EQUINE INFLUENZA-VIRUS/

The single radial haemolysis (SRH) technique in agarose gel and ion ag ar gel relative to the haemmaglutination inhibition (HI) technique was compared in 210 horse serum samples, of which 150 presented a positiv e HI reaction to influenza virus A/equi/l/Santiago 77 (H7N7) and A/equ i/2/Santiago 85 (H3N8) strains isolated in Chile. With both strains, n o significant differences (p > 0.05) were observed between HI and SRH in agarose gel, but significant differences (p < 0.05) were observed b etween HI and SRH-ion-agargel, and between SRH-agarose-gel and SRH-ion -agar-gel. The sensitivity for A/equi/l/Santiago 77 (H7N7) strain was 100% for HI and SRH-agarose-gel; 100% for HI and SRH-ion-agar-gel; and 99% for SRH-agarose-gel and SRH-ion-agar-gel. The specificity was 65% for HI and SRH-agarose gel; 37% for HI and SRH-ion-agar-gel; 54% for SRH-agarose-gel and SRH-ion-agar-gel. The sensitivity for A/equi/2/San tiago 85 (H3N8) strain was 96% for HI and SRH-agarose-gel; 99% for HI and SRH-agar-gel; 97% for SRH-agarose-gel and SRH-ion-agar-gel. The sp ecificity was 82% for HI and SRH-agarose-gel; 82% for HI and SRH-ion-a gar-gel; 85% for SRH-agarose-gel and SRH-ion-agar-gel. A significant c hange (p < 0.05) in the negative to positive results between HI and SR H-agarose-gel was detected for the A/equi/l/Santiago 77 (H7N7) strain; between HI and SRH-ion-agar-gel and between SRH-agarose-gel and SRH-i on-agar-gel. For the A/equi/2/Santiago 85 (H3N8) strain a significant change between HI and SRH-ion-agar-gel was detected. Comparisons betwe en the three techniques with the two strains showed significant correl ations (p < 0.05) Considering the advantages of SRH, it is concluded t hat in Chile SRH-agarose-gel and also SRH-ion-agar-gel can be used to detect antibodies against equine influenza virus, A/equi/l/Santiago 77 (H7N7) and A/equi/2/Santiago 85 (H3N8) strains.