Effective treatments have made malaria rare in the U.S.
DEAR DOCTOR K: I am traveling abroad in a few weeks. My travel clinic has prescribed antimalarial medication. Can you tell me more about malaria and how to prevent it?
DEAR READER: Malaria is a serious disease caused by the Plasmodium parasite. The parasite is not found today in the United States or Canada, but it is common in areas to which North Americans travel: Africa, Asia, and Central and South America. The U.S. Centers for Disease Control and Prevention estimate that there are more than 200 million new cases of malaria each year around the world.
The good news is that there are only 1,000-2,000 cases of malaria each year reported in the U.S. That's because most people traveling to parts of the world with malaria take antimalarial medications.
You contract malaria when you are being bitten by an infected mosquito. Once the parasite enters your body, it infects and multiplies inside your liver and red blood cells. Symptoms of malaria include:
- High fever (up to 105 degrees Fahrenheit) with shaking chills,
- Profuse sweating,
- Fatigue,
- Headache,
- Muscle aches,
- Abdominal discomfort,
- Nausea, vomiting,
- Feeling faint when standing up or sitting up quickly.
Without treatment, malaria sometimes can be fatal.
Anyone traveling to a region of the world that has malaria should take preventive medication. You start taking these medications before your trip starts and continue taking them for several days to weeks after you return.
There are four antimalarial medications most commonly prescribed in the U.S. for foreign travel:
- CHLOROQUINE (Aralen) is the most commonly prescribed drug for travelers headed to countries where there are no drug-resistant strains of malaria.
- MEFLOQUINE (Lariam) is the treatment of choice for travel to areas with high levels of chloroquine-resistant malaria parasites.
- DOXYCYCLINE (Vibramycin) is usually prescribed for travelers who can't take chloroquine or mefloquine.
- ATOVAQUONE AND PROGUANIL (Malarone). This combination drug is prescribed to prevent chloroquine-resistant malaria when you are traveling in areas where there is a higher rate of that kind of malaria.
In addition to one of these drugs, you also may need to take a medication called primaquine when you return home. This extra precaution further reduces the risk that you will develop malaria, even if you were taking an antimalarial drug during your trip.
To further reduce your risk, do your best to prevent mosquito bites. The following steps can help:
- When possible, stay indoors in well-screened areas, especially at night when mosquitoes are most active.
- Use mosquito nets and bed nets. Treat the nets with the insect repellent permethrin.
- Wear clothes that cover most of your body.
- Use an insect repellent that contains DEET or picaridin. Apply directly to your skin.
- Apply permethrin to clothing.
If you do develop malaria, fortunately, effective treatments are available.
Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.