RT-PCR amplification detects inactivated viruses in water and wastewater

Nucleic acid (NA) amplification techniques are useful to detect viruses in water and other environmental samples because they are highly sensitive, sp ecific and can detect fastidious enteric viruses that do not grow well or n ot at all in cell cultures. However, RT-PCR was found to detect inactivated viruses. In terms of risks to public health this constitutes a false posit ive result, as inactivated viruses are no longer infectious. When polioviru s type 1 and coliphage MS2 were studied for (a) persistence in water and se wage and (b) inactivation in water by free chlorine, chlorine dioxide and U V radiation, RT-PCR assays underestimated virus inactivation. The use of mu ltiple RT-PCR amplification sites, larger RT-PCR genomic targets and immuno capture RT-PCR sometimes reduced, but did not eliminate, the discrepancy be tween loss of infectivity and loss of RT-PCR titre. Virus presence based on RT-PCR detection must be interpreted with caution when predicting human he alth risks. (C) 1998 Published by Elsevier Science Ltd on behalf of the IAW Q. All rights reserved.