SCIENCE

A Mysterious Epidemic Plaguing Central America May Be Linked To Climate Change

"If it turns out that heat stress is causing kidney disease, it may be relevant throughout the world."
A worker hauls harvested sugar cane in the town of Chichigalpa, Nicaragua.
A worker hauls harvested sugar cane in the town of Chichigalpa, Nicaragua.

A mysterious disease has been sweeping through the sugar cane fields of Central America, with more than 20,000 laborers dying from it over the past decade. As of 2012, it had killed the husbands of more than 100 women of the 250 families living on one island in Nicaragua, giving rise to the grim nickname “Island of the Widows.”

“Chronic Kidney Disease of nontraditional causes,” as researchers have called the condition, attacks the kidneys and prevents the body from eliminating waste and excess fluid. As the name suggests, no one really knows what causes it. A new report, however, shows that researchers may be getting closer to an answer. And there are signs that a solution, too, could be close at hand.

Some studying the epidemic have wondered if toxins like pesticides or heavy metals may be making the workers sick, but Richard Johnson, a kidney specialist at the University of Colorado Anschutz Medical Campus, had a different theory. About four years ago, when Johnson first heard about the deaths in Central America, he wondered if chronic dehydration might be a factor. Laboring in the sugar fields is hard, hot work, and there's been increasing evidence that dehydration may cause kidney damage. During the harvest season, sugar cane workers toil in extreme heat for long hours, and they don’t necessarily have access to fresh water.

The research Johnson and his team conducted in Nicaragua and El Salvador, published last week, confirmed at least part of his theory. They found that the laborers suffered serious dehydration on a daily basis, and routinely worked in conditions exceeding the recommended heat standards of the U.S. Occupational Safety and Health Administration. This research could also help answer another question Johnson has been pondering: Could the 20,000 people who died in Central America be victims of the first epidemic caused by global warming?

“We’ve been worried that climate change could have big health effects,” he told The Huffington Post. “If it turns out that heat stress is causing kidney disease, it may be relevant throughout the world, particularly in hot areas.”

As Johnson laid out in his paper in the American Journal of Kidney Disease, temperatures have been rising in El Salvador since 1980, as have the number of extremely hot days. That, along with a growing global water shortage, suggests the epidemic in Central America could occur elsewhere around the world. In fact, a similar outbreak of chronic kidney disease has already been observed among workers in the rice paddies of northern Sri Lanka.

“We’re beginning to think that this might be a lot more common than we think,” he said. “As populations expand and you have areas that are arid or with drought, it’s going to be one of the major issues moving forward.”

One group is trying to make a difference. In recent months, Jason Glaser, co-founder of the La Isla Foundation, a nongovernmental organization dedicated to addressing the epidemic, has met with officials from the United States, Guatemalan, Costa Rican and Mexican governments.

This summer, Costa Rican President Luis Guillermo Solís Rivera announced a national regulation to limit heat stress and dehydration among manual laborers -- the first time that a government has framed the fight to curb kidney disease by focusing on those factors. The new regulation will require companies that employ laborers in tropical conditions to provide their workers with water, rest and shade.

Glaser’s group has worked alongside OSHA, which has a number of projects in Latin America, to develop a program that addresses the disease through a multi-pronged effort involving research and policy recommendations. So far, the results have been promising: Kidney function appears to be stabilizing among the workers, he said, and their productivity has gone up by 40 percent.

Perhaps that last statistic explains why companies are beginning to come around, too. When Glaser first began to fight the epidemic, almost every company he contacted refused to address the problem. But now, he says, nearly 20 percent of sugar cane companies are taking measures to help prevent chronic dehydration, and more companies appear to be on the verge of change. “It’s an excellent start,” he said. “Because before, it was zero.”

Johnson’s paper follows on earlier research suggesting a link between kidney ailments and climate change. Last year, a study for the Urologic Diseases in America Project examining instances of kidney stones in five major cities showed that as temperatures rose, so did the risk of kidney stones.

Ultimately, Glaser said, the next step will be to mechanize the sugar cane industry.

If left unchecked, this disease will bankrupt these countries," he said. "We can prevent it with better work solutions, but mechanization is probably the best way to help it."

Of course, mechanization could bring with it a new set of problems -- not least of which would be widespread unemployment among the sugar cane workers.

“If you do this sloppily, you replace one thing with another, which is all these out-of-work men in the middle of the drug war,” said Glaser. “So that is the responsibility now on my shoulders.”

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