YOKOSUKA NAVAL BASE, Japan — If you have sickle-cell anemia or sickle-cell trait, talk to the doctor before tackling Japan’s highest mountain.

That’s the gist of a Yokosuka Naval Base public awareness campaign after two USS John S. McCain sailors were evacuated off Mount Fuji late last month.

The base’s Morale, Welfare and Recreation division will take about 1,500 people up the mountain this year and is just halfway into climbing season, said MWR outdoor oecreation director Steve Marksberry.

“We figure on having one evacuation per 1,000 people — we train for that,” Marksberry said Friday. “These two incidents happened almost simultaneously — that was odd.”

On July 28 — right about the same time and about 700 feet apart — the two men were immobilized due to the pain created by sickle cell at high altitude. Both men were taken off the mountain, hospitalized and are now back at work, Marksberry said.

Two years ago, Yokosuka had four cases of sickle-cell sickness on Mount Fuji; two of those men lost their spleens, said Cmdr. Vish Pothula, U.S. Naval Hospital Yokosuka’s director of surgical services.

“We advertised heavily afterwards, and we had no cases in 2005,” Pothula said. “It’s extremely important to get the word out.”

Pothula, who is submitting a paper on sickle cell to the Journal of the American Medical Association, tells what happened.

“The combination of low oxygen at high altitudes and dehydration during exertion can cause red blood cells to deform into a sickle-shape, compared to a normal oval-shape,” Pothula said. This causes the spleen to malfunction, he added.

Either sickle-cell trait (passed down by one parent) or sickle-cell disease (passed down by both parents) is found largely in people of African descent. The trait is an evolutionary benefit due to the protection it offers to malaria, Pothula said.

In the United States, one out of 12 black Americans has sickle cell trait; one out of 600 has the disease, according to the National Institutes of Health. In the U.S. Navy, about 8 percent of black recruits carry sickle-cell trait, according to a 1973 study.

Not everyone who has sickle cell trait will have problems climbing, Marksberry said. “There are probably more people going up with it that we don’t hear about,” he said. “It can be a hit-and-miss thing.”

And plenty of other things can go wrong on Mount Fuji, like falls, dehydration and lack of preparaton for the 43-degree weather at the summit, he said. But with 13 more Mount Fuji trips on the schedule this climbing season, a mid-season reminder doesn’t hurt, Marksberry said. “If you have the trait and know about it, see your doctor,” he said. “That’s what we’re preaching about.”

Sign Up for Daily Headlines

Sign up to receive a daily email of today's top military news stories from Stars and Stripes and top news outlets from around the world.

Sign Up Now