Comparative sensitivity of counterimmunoelectrophoresis and double immunodiffusion tests for identification of influenza A viruses in birds isolates

Abstract

Fifty cloacal swab specimens which were found positive by haemagglutination after one or two passages in chicken embryonated eggs were examined for the presence of influenza A virus by counterimmunoelectrophoresis (CIE) and double immunodiffusion (DID) with anti-matrix and anti-nucleoprotein sera. CIE was as sensitive as DID with the anti-nucleoprotein serum and more sensitive with the anti-matrix serum when virus from allantoic fluid was concentrated with acid and disrupted with the detergent Sarcosyl. However, when the concentration step was by-passed and the virus was disrupted with Sarcosyl alone, CIE was substantially more sensitive. Forty-nine samples were positive for type A influenza with the anti-matrix serum and 37 with the anti-nucleoprotein serum. By DID, only 16 could be identified with the anti-matrix serum and none could be typed with the anti-nucleoprotein serum. Since CIE with anti-matrix serum is more sensitive than the DID tests, even with unconcentrated infected allantoic fluid, the CIE test is preferred for large-scale identification of influenze A virus in bird isolates.