Pretreatment to avoid positive RT-PCR results with inactivated viruses

Enteric viruses that are important causes of human disease must often be detected by reverse transcription-polymerase chain reaction (RT-PCR), a method that commonly yields positive results with samples that contain only inactivated virus. This study was intended to develop a pretreatment for samples, so that inactivated viruses would not be detected by the RT-PCR procedure. Model viruses were human hepatitis A virus, vaccine poliovirus I and feline calicivirus as a surrogate for the Norwalk-like viruses. Each virus was inactivated (from an initial titer of approximate to10(3) PFU/ml) by ultraviolet light, hypochlorite or heating at 72 degreesC. Inactivated viruses, that were treated with proteinase K and ribonuclease for 30 min at 37 degreesC before RT-PCR, gave a negative result, which is to say that no amplicon was detected after the reaction was completed. This antecedent to the RT-PCR method may be applicable to other types of viruses, to viruses inactivated in other ways and to other molecular methods of virus detection. (C) 2002 Elsevier Science B.V. All rights reserved.