THE REVERSE TRANSCRIPTION-POLYMERASE CHAIN-REACTION FOR THE DIAGNOSISOF PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME - COMPARISON WITH VIRUS ISOLATION AND SEROLOGY

A single-tube reverse transcription polymerase chain reaction (RT-PCR) assay for the detection of porcine reproductive and respiratory syndr ome (PRRS) virus in blood samples from infected pigs was developed. Th is test was assessed for sensitivity and application as a rapid diagno stic tool by comparison with virus isolation and detection of PRRS vir us antibody in blood. The RT-PCR test was slightly more sensitive than virus isolation for detection of virus in serum and markedly more sen sitive than virus isolation from plasma from experimentally infected p igs. The RT-PCR test was also applicable when using whole blood-impreg nated filter paper discs, with 94% of the specimens taken by this proc edure being positive when compared to RT-PCR performed on serum. PRRS viral nucleic acid was detected in blood samples as early as 24 h afte r infection and persisted for some time, whereas circulating antibody to PRRS virus was not detected in the same animals until 9 days after infection. These results indicate that the RT-PCR may be an useful tec hnique for the early identification of PRRS viral nucleic acid in bloo d samples of infected pigs. (C) 1998 Elsevier Science B.V. All rights reserved.