Using PCR in soil samples

As discussed before, not only is WNS spread from one bat to the next but it is also transferred to new caves by means of human transport when individuals do not clean off their boots, equipment, and belongings.  How did biologists come to determine that humans were a means to transfer the disease further than simply speculating?  The use of PCR has helped biologists to determine this fact, with studies showing that the fungus G. destructans is present in soil samples within caves that have had confirmed cases of WNS.  From this evidence, biologists were able to determine that environmental reservoirs, such as soil, play a key role in the spread of WNS.