Statistical correlation between enterovirus genome copy numbers and infectious viral particles in wastewater samples

Aims: Classic virological tests are time consuming and labour-intensive; realtime RT-PCR has proven to be a fast method to detect and quantify enterovirus genomes in clinical and environmental samples. This method is unable to discriminate between infective and noninfective enterovirus particles; few clinical studies have compared real-time RT-PCR and viral culture. We wondered if the enterovirus genome quantification could be correlated to the infectivity. Methods and Results: We used the statistical approach to verify our hypotheses to correlate data, obtained by the standard method (most probable number of cytopathic units—MPNCU) and molecular test (real-time RT-PCR), on wastewater treatment plant samples. Chi-squared test was used, considering several cut-off values (‘50’-‘100’-‘200’ genome copy numbers), to determine statistical significance in comparison of the two methods. Chi-square value was not significant when cut-off of 50 (P = 0Æ103) and 100 (P = 0Æ178) was assumed but was significant with cut-off of 200 (P = 0Æ044). Conclusion: This limit, 200 genome copy, could be used as cut-off value to indicate enterovirus survival in environmental monitoring. Significant and Impact of the Study: To introduce a fast procedure that is able to compensate for disadvantages of cell culture method for viral environmental analyses.