Nearly 10,000 people are thought to be at risk for becoming ill with hantavirus pulmonary syndrome during their stay at Yosemite National Park between June and August, according to Reuters. Of those individuals, 2,500 live outside of the United States, said Dr. David Wong.

U.S. health officials have sent warnings out to 39 other countries, in hopes of urging those possibly infected to seek treatment. So far, the lung disease has killed two people and put four others in the hospital. All have been U.S. citizens.

"I want people to know about this so they take it seriously," Wong said to the news source. "We're doing our due diligence to share the information."

Officials believe that some could develop the disease over the next month or so, as the hantavirus can incubate for up to six weeks after exposure. Infection has never been known to transmit between humans, rather, it is carried by mice, and individuals will contract it through inhaling viral particles from rodent feces and urine. It can also be spread by eating contaminated food or being bitten from an infected mouse.

Last week, officials shut down the insulated "Signature" tent cabins after finding deer mice inside the walls. Most of the victims so far were staying in one of those units while they were at Yosemite.

The illness begins with symptoms similar to the flu, but there is no cure. Anyone that shows signs must be hospitalized and experts say that the virus kills 36 percent of the individuals who contract it.

Businesses and organizations that rely on tourism need to prepare for a plethora of situations. Working with a business continuity consultant will better prepare employees for many events. Along those same lines, communicable diseases run the risk of turning individuals away. It's important for companies to keep customers safe and continue to put their best foot forward.