RT-PCR-ELISA as a tool for diagnosis of low-pathogenicity avian influenza

A one-tube reverse transcriptase/polymerase chain reaction coupled with an enzyme-linked immunosorbent assay (RT-PCR-ELISA) was developed for the rapid detection of avian influenza virus (AIV) in clinical specimens. A total of 419 swab pools were analyzed from chickens experimentally infected with low-pathogenicity AIV, from wild aquatic birds, and from domestic ducks. The AIV was detected in 32 swab pools by RT-PCR-ELISA compared to 23 by virus isolation (VI) in embryonated specific pathogen free (SPF) chicken eggs. Thus, 39% more specimens were positive by RT-PCR-ELISA than by VI. Two of the twenty-three VI-positive specimens were negative when tested by RT-PCR-ELISA. The diagnostic sensitivity and specificity of the RT-PCR-ELISA was 91% and 97%, respectively, using VI in SPF eggs as the gold reference standard.