Cases of malaria increase in U.S. due to international travel


The United States Center for Disease Control and Prevention recently said the number of malaria cases in the U.S. has increased by 48 percent since 2008.

The Morbidity and Mortality Weekly Report, released on Nov. 1 by the CDC, said that 1,925 cases of malaria were confirmed in 2011, which was the highest number of cases since 1971.

The CDC said the majority of cases were reported in people who had traveled to regions with malaria endemics. Only five of the cases reported in 2011 were locally contracted and not imported.

Malaria is caused when a parasite is transferred from an infected Anopheles mosquito to a human. A mosquito that is not infected may transfer the disease from an infected human to another human. An infected mosquito does not have side effects.

Symptoms include fever, chills, headache and nausea. Death can occur from associated complications. Proper diagnosis and prompt treatment can cure the disease.

Malaria cases are decreasing worldwide, but cases among international travelers appear to be increasing. Kristin Michel, an associate professor of biology at Kansas State University who studies the Anopheles gambiae s.s. mosquitoes, said the use of available prevention measures by travelers is inadequate.

"The CDC provides actual maps and very good recommendations for travelers," Michel said. "Anybody who travels outside of the U.S. into potentially endemic area needs to consult the CDC website and/or their physician and ensure that they have the right prophylaxis."

Because travelers are not utilizing prevention measures such as prophylaxis and bed nets, researchers continue to look for ways to eradicate the disease.

"What we are trying to figure out is what factors are present in the mosquito that either enable or hinder parasite development," Michel said. "So, specifically we work on the immune system of the mosquitoes, because like we do, the mosquito has an immune reaction against parasites when it is infected. And what happens is a mosquito kills a lot of the parasites but not all of them, so the ones that make it through can get transmitted."