K-State Research and Extension News
November 21, 2013
Share  Email the story

U.S. Malaria Cases Increase with International Travel

MosquitoResearcher at K-State Hopes to Discover New Prevention Method

MANHATTAN, Kan. -- The number of malaria cases in the United States is rising, a trend that can be linked to the increasing amount of international travel and inadequate use of prevention methods.

PICTURED: Researchers at Kansas State University are working with the Anopheles gambiae s.s. mosquito to understand more about how malaria is spread and the mosquito’s immunity to the parasite.

Additional Information for Travelers

If you are planning to travel internationally, please visit the following resources for more information:

  • Health-care providers should be familiar with prevention, recognition, and treatment of malaria and are encouraged to consult appropriate sources for malaria prevention and treatment recommendations.  Consult with your physician before and after traveling internationally.

  • Detailed recommendations for preventing malaria are available to the general public 24 hours a day online.

  • To get information about malaria in a particular location and check for the  recommended malaria prophylaxis, visit the interactive CDC malaria map application online.


Malaria is a disease caused by a parasite transmitted through the saliva of infected female Anopheles mosquitos. The initial symptoms of this disease are often compared with those of a severe case of the flu, so people will often experience fever, chills, headaches and nausea.


In 2011, five people died in the U.S. from malaria or associated complications, but malaria is a curable disease if diagnosed and treated promptly with the proper medications. 


“The root of transmission is really from a human to a mosquito and from a mosquito to a human,” said Kristin Michel, an associate professor of biology at Kansas State University who studies the Anopheles gambiae s.s. mosquitoes, the species most responsible for malaria transmission in Africa.


A mosquito can become infected when they take a blood meal on an infected human and transfer that disease to another human.   The mosquito acts as a vector, but different from humans, the mosquito vector does not suffer from the presence of the parasite.


Globally the number of malaria cases in endemic regions is decreasing, but international travel appears to be growing steadily and the use of appropriate prevention measures by travelers is still inadequate.


Michel said that because virtually all of the malaria cases detected in the U.S. are acquired outside of the U.S., international travelers are increasing their risk of acquiring malaria when they visit malaria endemic areas.  This elevated risk also includes U.S. military personnel stationed in malaria endemic areas.   Anyone traveling internationally needs to be more cautious about where and when they travel.


More than two-thirds of the 2011 cases were imported from Africa and the cases show seasonal peaks in January and August, which are likely correlated with peak travel times to African destinations related to winter and summer holidays.


Malaria Map, CDC“The CDC provides actual maps and very good recommendations for travelers,” said Michel.  “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.”

AT RIGHT: Before traveling to an endemic country, like those shown on the map, travelers need to research the area and make sure they take the proper measures to reduce their risk of acquiring malaria.  Photo courtesy of CDC.

Michel says that to prevent malaria transmission, travelers can use a bed net at night when they sleep, try to avoid going out in the evenings when mosquitos are most likely to bite and use repellents or insecticide on their clothing, but chemical prophylaxis is still by far the most effective prevention tool.


Chemical prophylaxis involves taking an antimalarial medication before and during traveling to an endemic area to build up a significant level of drug in the human body the entire time of travel she said.   If infected mosquitos bite travelers, the parasite is killed immediately before it is able to infect their system.  


The number of people who take the necessary measures to protect themselves from malaria are increasing but still less than half.  This is why researchers, like Michel are looking for new ways to control and eventually eradicate malaria.

With funding from the National Institutes of Health and K-State Agricultural Experiment Station, her lab is currently working directly with the mosquitos that transmit malaria.


“Malaria control is really 90 percent or more mosquito control,” said Michel.  “What we are trying to figure out is what factors are present in the mosquito that either enable or hinder parasite development. So, specifically we work on the immune system of the mosquitos, 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.”


Through research, her lab is trying to understand why some parasites can get through and if it is possible to prevent this by chemical means.  If found, this information could help develop a new way to fight malaria.


To learn more about the research done in the Michel Laboratory, please visit http://www.k-state.edu/michellab/.

K-State Research and Extension is a short name for the Kansas State University Agricultural Experiment Station and Cooperative Extension Service, a program designed to generate and distribute useful knowledge for the well-being of Kansans. Supported by county, state, federal and private funds, the program has county Extension offices, experiment fields, area Extension offices and regional research centers statewide. Its headquarters is on the K-State campus, Manhattan.

Story by: Kaitlin Morgan
K-State Research & Extension News

Kristin Michel, kmichel@ksu.edu