As the director of the National Museum of Natural History, it isn't surprising that Kirk Johnson believes that people should make use of his museum's collections. What is surprising is the group of people whom Johnson is addressing: infectious disease researchers.

In a recent op-ed for the Proceedings of the National Academy of Sciences, Johnson and his co-authors Diane DiEulis from the U.S. Department of Health and Human Services, Stephen S. Morse from the School of Public Health at Columbia University and David Schindel, also from the Natural History Museum, wrote that researchers and public health officials need to start paying more attention to the vast collections resources available in research institutes and museums, as well as funding these highly valuable historic specimens.

Museum collections can help public health officials identify new diseases, learn their origins, and determine how to best stop them.

Even collections that appear at first to be irrelevant to medical research—including decades worth of dead mice—can prove useful.

In 1993, a mysterious new disease emerged and began killing people in the American Southwest. The mortality rate was initially around 70 percent as doctors struggled to understand what would eventually be identified as a hantavirus, which are a group of viruses known to be associated with rodents.

Nobody knew whether this was an exotic virus recently introduced to the area or if it was something that was already present. To find out, researchers turned to frozen rodents at the Museum of Southwest Biology at the University of New Mexico as well as the Museum at Texas Tech University. Both institutions had collected the animals as part of field biology programs—740 frozen mice were tested, dating back to 1979. It turned out that the dangerous strain of hantavirus had been endemic all along.

By combining this data with analysis of the genomes of hantaviruses, researchers concluded that hantaviruses had been following rodents around in North America for at least seven million years. So why did humans suddenly start getting infected?

The El Niño weather cycle had produced unusually heavy rains, which led to more food available to rodents, causing an explosion in their population. With the human population of the region also at a record high, maximum rodents plus maximum humans resulted in a lot of contact between the two groups.

Access to historical collections made this conclusion possible.

"Collections can provide short-cuts to public health responders looking for the origins and distribution of disease agents," Johnson and the co-authors wrote, "but only if the collections are accessible and well documented."

Those "ifs" aren't guaranteed. In March of 2016, the National Science Foundation announced massive cuts in funding for collections in support of biological research, part of a trend of reduced funding for collections that has been going on for years.

Without proper budgets, collections that date back hundreds of years may not be catalogued, digitized or even physically maintained in a manner consistent with modern fire codes. Smaller institutions are at particularly high risk of being pushed entirely into oblivion. But even the NMNH has been reduced from a high of 122 curators in 1993 to a current low of 76.

Chicago's venerable Field Museum no longer has a curator of fishes. Grants and government budget cuts have gradually forced museums farther away from the research and collections management that provide their real scientific value in favor of a focus on entertainment for the public.

Yet biological samples of all types may eventually help to trace and fight infectious diseases, even when originally gathered for other scientific purposes.

Johnson tells Smithsonian.com that the disease which “everyone has in mind right now is Zika virus. Most people would not realize that we have the National Mosquito Collection, which was built for something like this.”

The collection, stored in Suitland, Maryland, is managed as part of a collaboration between the Museum of Natural History and the Walter Reed Army Institute of Research. Thousands of mosquitoes collected from around the world are kept for research by scientists ranging from entomologists to virologists looking to sequence genetic material in search of lurking viruses.

“They are learning a lot about the range of mosquitoes and Zika virus,” says Johnson. “Think about that, you wouldn't be able to do this if you didn't have a collection like that.”

“One of the obvious things about natural history museums' collections, so many new diseases are sylvatic,” says William Petri, chief of the University of Virginia's division of infectious diseases and international health. Sylvatic diseases are those which are primarily transmitted between animals but may also affect humans. Rabies, plague and ebola are all examples.

“Like yellow fever. Same thing for Zika virus,” says Petri. “We know that Zika has sylvatic transmission in Old World primates. There are probably additional viruses that go from animals to humans. The National Museum of Natural History has tons of these samples. We can work backwards if we need to to find animal reservoirs for viruses we don't even realize are there yet.”

“It is a big complicated thing to preserve and archive biodiversity,” says Johnson. “We're just at the beginning of it. It's a big planet and we're still finding new organisms... The human population continues to climb... This expanding population is going to continue to encounter new diseases as people are forced to spread out. There will be more human-wildlife interactions.”

Some of those new organisms are already waiting in museum collections but haven't been identified as new species yet. Every animal on Earth consists of not only its own cells, but also the bacteria and viruses that survive in and on it. Those bacteria and viruses wait in drawers and freezers to be discovered and studied.

There are tens of thousands of institutions holding collections like these—museums, hospitals, universities, veterinary and medical colleges, zoos, botanical gardens, and even private companies, Johnson and co-authors write.

“What I've used personally is. . . viral repositories from people that have been saved over the years,” says Petri. “I've used collections from the the International Centre for Diarrhoeal Disease Research in Bangladesh. That's allowed me to understand some things of importance. We understand now why the polio virus failed in some countries with poor nutrition. . . we discovered that the malnourished children had a weaker immune response to the vaccine, because we had the archive of samples in Bangladesh.”

Losing existing collections means losing information forever. When a new sylvatic disease is found to start infecting humans, new samples cannot tell researchers what has been happening historically.

“You can start collecting now in Central Asia,” says Johnson, “but you don't have the history of collections from the 1800's. You don't have the historic materials there. …One of the challenges is that you can't just start it up, though obviously you can start collecting new materials.”

Johnson and his co-authors advocate not only for restoration of lost funding for collections management, but also for greater communication between museums and disease researchers. The authors “propose a new and interdisciplinary enterprise that will produce new collections of organisms, microbes, tissue and fluid samples,” standardized across disciplines and countries so that information is available to anyone, anywhere, immediately.

“I'm sitting on top of the largest collection of natural history specimens in the world,” says Johnson. “How do I share this? If you're a specialist who works with starfish, for example, you know who the other starfish specialists are. But we don't have a system for doing this with everything.”