Around the World, Warmer Temperatures Mean More Infections

"We thought this was probably the best example of the potential of global warming impacting human health, as far as available evidence goes," McLaughlin said.

Mosquitoes and Ticks Spreading

Across the world, another microscopic bug, malaria, has caused havoc in the lowlands of Africa. It is transmitted by mosquitoes, which thrive in hot, damp areas near stagnant bodies of water.

Until recently, the mile-high city of Nairobi, Kenya, was relatively free of the disease.

But now Nairobi, despite its elevation and climate, is in the midst of a malaria outbreak.

And like the Alaskan bacterial outbreak, warmer temperatures are to blame, say scientists with the University of Michigan, the University of Hawaii, the University of Barcelona in Spain and the London School of Hygiene and Tropical Medicine.

In their report, published in last month's Proceedings of the National Academies of Science, they determined that the mosquitoes were thriving in part because it was steadily getting warmer in East Africa's higher altitudes.

This comes as no to surprise to public health researcher Dr. Paul Epstein, the associate director of the Center for Health and the Global Environment at Harvard Medical School and a medical doctor trained in tropical public health.

Along with mosquito-borne diseases like malaria, yellow fever and West Nile virus, tick-borne diseases also are an increasing problem, he said.

When winters are milder, more deer ticks reproduce year-round, transmitting infections such as Lyme disease and Rocky Mountain Spotted Fever.

According to the Centers for Disease Control and Prevention, Lyme disease cases increased from 11,700 cases in 1995 to 21,304 cases in 2005. This year could be a bad one for diseases spread by warm weather-loving insects -- 2005 was the warmest year in the last 100 years, said NASA scientists.

This not only causes more biting bugs to flourish, it also indirectly impacts humans' health in other ways. For example, when trees are weakened by drought, such as what's happening in pine forests from Alaska to Arizona, beetles eat the bark, weakening the trees even more and making them prone to wildfires, Epstein said.

And those wildfires not only release more harmful carbon dioxide and soot into the atmosphere, they trigger another major health effect of global warming: asthma.

Ragweed Loves Carbon Dioxide

For years, doctors have noted an increase in asthma and allergies.

While no one can link the increase directly to global warming, Epstein has strong evidence: When ragweed -- one of the most allergenic plants on the planet -- is grown in a carbon dioxide-rich environment, it grows 10 percent faster than normal, but produces 60 percent more pollen.

While that's good for the plants, it's bad for people. Most people are allergic to something, and often it is plant pollen. In children especially, being exposed to an allergen can trigger a dangerous asthmatic response, or inflammation of the lungs.

"As we see the seasons change and warmer weather has an earlier arrival in the spring, we're beginning to see shifts in asthma and allergies," Epstein said.

What's worse, he said, is that the tiny dust particles emitted from diesel fuel attach to plant pollens, and these diesel particles further irritate the lining of the lung.

Though there haven't been published studies showing that the rise in asthma cases is tied to global warming, Epstein said it is.

"We're seeing it and we're all experiencing it," he said.

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