To destroy snail mail: Is this the sole solution for anthrax contaminated letters?

Suspicious packages, strange addresses on envelopes and/or the presence of particular powders: these are the most popular aspects of letters containing Bacillus anthracis. Since the World Trade Center tragedy, alarmism about chemical or biological attacks is always in force. The Italian Ministry of Foreign Affairs introduced new procedures to be followed in case suspected anthrax letters are identified (Ministry of Health PROT. 400.3/120.33/4786 of 23/10/2001). Scientists have to collect samples from surfaces and infectious waste have to be placed in autoclavable bags for decontamination. After the sterilization, mails and packages are burnt thus eliminating every biological trace present on their surface. As a matter of fact, after sterilization, DNA is still present and can be analyzed for forensic purposes: for this reason, here we report on the importance of preserving sterilized substrates. We recreated false infected mails with biological traces on their surfaces, sterilized them and, subsequently, we took samples of biological stains and processed them for DNA quantification and typing. We recreate different time conditions consistent with those of the postal service too. Real-Time PCR and DNA typing showed that, even if sterilization destroys the bacillus, human genomic traces still persist and we obtained both complete and partial profiles of samples' donors. To conclude, the problem of anthrax contaminated letter call for peculiar and standardized procedures; nonetheless, we show that burning evidences after the sterilization process does not appear to be the best solution since there is a loss of biological material which could be decisive for forensic purposes.