Like all sports that appeal to the extreme set, caving is risky. Beyond slips, falls and scrapes, spelunkers chance a host of rare, nasty diseases from cave critters. Typical threats are histoplasmosis, rabies, leptospirosis and tick-borne relapsing fever.

Though most underground explorers understand the need for good ropes and headlamps, fewer think about the diseases they can catch beneath the surface, said Ricardo Pereira Igreja, a doctor and professor of infectious disease in Brazil.

“People all over the world now are exploring caves for the nature and ecology. For some it’s very spiritual,” said Igreja, of the Federal University of Rio de Janeiro. “I think that’s good, but it does come with some threat.”

For a casual tourist, like the 500,000 annual visitors to Carlsbad Caverns National Park in New Mexico, walking through a cave is essentially as safe as walking down the street. It is the sport cavers, those who crawl through muck and mud into little-explored crevices, that must protect themselves from things living on bats, rodents, ticks and other bugs, Igreja said.

Igreja surveys the classic and emerging cave-borne diseases in the June 10 Wilderness and Environmental Medicine. We’ve collected a gallery of the offending cave fauna, along with tips about how to keep sickness away next time you’re slithering among the stalagmites. Note: None of these diseases are exclusive to caves. Strange bugs can strike almost anywhere.

Image: Wikimedia