Travel Medicine

Emerging Infectious Diseases and Other Conditions

Malaria

What is malaria?

Malaria is a disease caused by a parasite that is transmitted by the bite of an infected Anopheles mosquito. These mosquitoes are present in the tropics and subtropics in almost all countries.

Malaria is the most deadly of all tropical parasitic diseases. After the parasites enter the body by a mosquito bite, they disappear from the circulating blood within minutes, and gather in the liver. After several days, parasites emerge from the liver and infect RBCs in the circulation. After several days, parasites break out from the RBCs and infect other RBCs, causing the symptoms of malaria.

What are the types of malaria?

Four species of malaria parasites can infect humans and cause illness:

Plasmodium falciparum
Plasmodium malariae
Plasmodium vivax
Plasmodium ovale

Only falciparum malaria is potentially life-threatening. Patients with severe falciparum malaria may develop liver and kidney failure, convulsions, and coma. Infections with P. vivax , P. ovale and P. malaria may cause less serious illness, but the parasites can remain dormant in the liver for many months, causing a reappearance of symptoms months, or even years, later.

What are the risks of acquiring malaria?

The risk of acquiring malaria depends on:

traveler's destination
duration of travel
place where the traveler will spend the evenings and nights. (Anopheles mosquitoes bite during nighttime hours, from dusk to dawn.)

What are symptoms of malaria?

Early stages of malaria may be similar to the flu. Symptoms may include:

fever
chills
headache
muscle ache
malaise
sometimes vomiting, diarrhea, and coughing

Can malaria be prevented?

Malaria can often be prevented by the use of antimalarial drugs and use of protection measures against mosquito bites.

Medications:
When planning to travel an area where malaria occurs, talk with your physician well in advance of your departure. Drugs to prevent malaria can be prescribed for travelers to malarious areas, but travelers from different countries may receive different recommendations, reflecting differences in treatment protocols as well as availability of medicines in different countries. Travelers visiting only cities or rural areas where there is no risk of malaria may not require preventive drugs, but an exact itinerary is necessary to determine what degree of protection may be needed.

According to the CDC, drugs recommended for prevention of malaria in travelers are: mefloquine, malarone, doxycycline, chloroquine. Strict adherence to the recommended doses and schedules of the antimalarial drug selected is necessary for effective protection.

Protection from mosquitos:
Be aware that you are still at risk for malaria even with the use of protective medication which sometimes does not work well.

To avoid mosquito bites, the CDC recommends that you:

Apply insect repellent to exposed skin. The recommended repellent contains 20-35 percent DEET .

Wear long-sleeved clothing and long pants if you are outdoors at night.

Use a mosquito net over the bed if your bedroom is not air-conditioned or screened. For additional protection, treat the mosquito net with the insecticide permethrin.

Spray an insecticide or repellent on clothing, as mosquitoes may bite through thin clothing.

Spray pyrethrin or a similar insecticide in your bedroom before going to bed.

Note: According to the CDC, vitamin B and ultrasound devices do not prevent mosquito bites.

How may malaria be treated?

The Centers for Disease Control (CDC) recommends that:

Travelers who become ill with a fever during or after travel in a malaria risk area should seek prompt medical attention and should inform their physicians of their recent travel history. Neither the traveler nor the physician should assume that the traveler has the flu or some other disease without doing a laboratory test to determine if the symptoms are caused by malaria.

Malaria symptoms can develop as early as 6-8 days after being bitten by an infected mosquito or as late as several months after departure from a malarious area, after antimalarial drugs are discontinued. Malaria can be treated effectively in its early stages, but delaying treatment can have serious consequences.

This page was last updated on: February 14, 2008.

For patient inquiries, call 1-800-492-5538 or click here to make an appointment.