Filter Paper for Preserving Insects, Bacteria, and Host Reservoir DNA

Sir, the recent report on “Utility of filter pa­per for preserving insects, bacteria, and host reservoir DNA for molecular testing” is very interesting (Karimian et al. 2011). Karimian et al. (2011) reported that “The filter paper method is a simple and economi­cal way to store, to preserve, and to distrib­ute DNA sam­ples for PCR analysis.” Many facts should be discussed. First, this work is only a sim­ple retrospective observational study. There is no economic analysis. No data on the cost, hence, it might not be pos­sible to conclude that the technique is an economical way. Second, Karimian et al. (2011) concluded on preservation. This might be an extrapolating summary. There must be the proposed mech­anism how the simple filter paper can preserve the sample. What the active gradi­ent in the filter paper that helps preserve must be clar­ified. It seems that the filter pa­per is only a good alternative sample collec­tion method.