According to the WHO, malaria is found in more than 100 countries in the tropics and sub-tropics visited by over 125 million travelers each year. Since the 1970s, malaria has been on the rise reappearing even in areas where it was thought to be eradicated. Current statistics indicate that worldwide, there are an estimated 2.7 million deaths, and 300 to 500 million cases of malaria annually. (Keystone, Preventing Malaria in International Travelers, Journal of Travel Medicine, Vol 8; 3; Dec 2001)
While several drugs are available for the prevention and treatment of malaria, different drug resistance patterns have emerged around the globe. It is therefore extremely important to consult a travel medicine specialist who is familiar with the resistance patterns in your destination. A false sense of security fostered by taking the wrong preventive drug can increase the risk of exposure.
Malaria is caused by any one of four parasites from the Plasmodium family, transmitted through the bite of the female Anopheles mosquito, which bites mainly in the evening and night hours. The risk of infection is highest at the end of the rainy season. Infection at altitudes over 1500 m (approx. 4921 ft.) is rare.
Symptoms of malaria are similar to the flu, with fever, chills, head-and-muscle aches, and possibly vomiting and diarrhea. Jaundice (yellowing of the skin) and anemia (too few red cells in the blood) may also occur. Symptoms will develop no sooner than seven days after exposure, but may take months to appear. WHO recommends that travelers who visit affected countries and develop a fever within three months of returning home be tested immediately for malaria The CDC recommends being tested for malaria if fever develops within one year of returning home.
Early diagnosis and treatment are essential— the most severe form of malaria, called falciparum malaria (caused by Plasmodium falciparum), can be rapidly fatal if treatment is delayed by more than 24 hours. Other forms of malaria are usually not life threatening, though the symptoms can come and go for years.
Malaria is especially severe in pregnant women, where it can prove fatal to the mother and the baby she's carrying. For this reason, it is strongly recommended that pregnant women not travel to malarious areas.
Several drugs are available to prevent or treat malaria. The choice of drugs will depend on several factors including the destination of travel and the health status of the traveler. It is extremely important to take the medicine exactly as directed, and for the length of time specified. Failure to follow instructions accounts for many cases of malaria in travelers.
In cases where access to medical facilities may not be possible in a timely manner, travelers will be given a "stand-by" drug (different from the one used for prevention). The stand-by drug should be taken as directed if fever develops while away from medical facilities, but medical help should be obtained as soon as possible.