There are sound, science-based reasons for taking a precautionary approach to white-nose syndrome by closing caves to nonessential human travel.
Humans are Likely Vectors
First, there is strong evidence for spread of WNS by people. The pathogenic fungus, Geomyces destructans, is widely distributed in Europe where it does not harm bats, clearly indicating it evolved in the Old World. It also appeared quite suddenly in the United States in a commercial cave and devastates bat populations here, suggesting a recent introduction. By far the most likely way WNS got to this continent was by hitching a ride on the gear or clothing of a person visiting caves on both continents. This is analogous to the historical introduction of smallpox to the New World and its devastating impact on American Indians.
The fact that white-nose is spread from bat to bat but has yet to move into the western U.S. or South America highlights the fact that the dispersal ranges of bats are limited and that the disease likely does need people to get to distant, new areas.
Quarantine Principles
There is a long, successful history of using quarantine to stop the spread of new diseases, particularly with diseases that result in massive mortality, as does WNS. Quarantine, for example, is responsible for the fact that we haven’t all died of ebola. In the case of WNS, cave closures are a means of quarantining infected caves from uninfected caves. The basic goal is to prevent, or at least minimize, the amount of contact and exchange between infected and uninfected people, or in this case, bat caves. Bats cannot be asked to comply with a quarantine. Humans, however, can be.
Decontamination is Better, but Not Best
Although asking or requiring people to follow decontamination procedures and restrict gear probably helps, it is unknown at this point whether they will be 100-percent effective in the field. It is also not known the degree to which people will follow the procedures, which are fairly exacting and can be very expensive.
Better Safe than Sorry
It may be that after we know more about the disease, closed caves can be reopened, but for the time being the best thing would be for people simply not to enter caves. We cannot wait for absolute proof or for the disease to spread to the whole country before we take the precaution of closing caves; rather we need to close caves now and stop visiting them until we know that it is absolutely safe. This gives the benefit of the doubt to the bats. After all, people can always visit caves again if it is determined to be safe, but we can never get bat species back if they go extinct, and it is unknown whether bat species that remain will be able to reoccupy white-nose-affected caves.
