Preventing Malaria On Tropical Travels

Tips from FTF's Doc Holiday on a topic of interest to any families heading to South America or Asia — malaria, its prevention and treatment strategies.

Annually, out of seven million travelers from the United States to malaria-endemic areas, 1,000 to 1,500 will contract the disease. Since studies done by pediatrician Sheila Mackell, MD at her Flagstaff, Arizona clinic revealed that 50% of travelers were not aware of malaria prophylaxis, there is great hope that educating travelers will lessen the number adversely affected by the disease.

Your family’s physician and pediatrician should be able to provide up-to-date information on antimalarial drugs and their efficacy, based on your travel itinerary and medical history. They should be taken exactly as prescribed, as overdosing of these potent medications can be fatal. Be sure to keep them out of the reach of children, and in childproof containers. United States residents should purchase antimalarials before traveling overseas as their quality outside the US may not be reliable.

Dr. Bill Fisher, professor of pediatrics at the Mayo Clinic in Minnesota (which coincidentally was founded a century ago by the physician who relocated from Indiana to Minnesota to avoid malaria), reminds families of the three essential steps in combating malaria:

1)  Prevent infection with insect control.
2)  Prevent illness with chemoprophylaxis.
3)  Prevent incapacitation with early therapy. 

Insect & Environment Control – Infection Prevention

Altering the environment to prevent infection should include the removal of any aquatic areas where insects breed, protection of the traveler with clothing and bedcovers, and the treatment of clothing and bednets with insecticide. Simple measures used by many travelers, such as burning mosquito coils, have been found to be about 80% effective in reducing insect population, though some physicians question the healthiness of prolonged exposure to smoke.

Insect control is most critical between dusk and dawn when the Anopheles mosquito is biting. This method is the safest preventative with the fewest side effects, and should be used in conjunction with medication. When your family is not in an air-conditioned, screened area, wear long-sleeved shirts and long pants and use insect repellent on exposed skin. The strongest repellents contain the compound DEET, which the American Academy of Pediatrics states is safe for children over the age of two months only if used in a concentration of 30% or less, and according to label instructions. Avoid applying it to little hands, which may end up in the mouth or around the eyes, and wash it off as soon as the risk of exposure has ended. Dr. Fisher recommends applying DEET only to healthy skin and not more often than every six hours. DEET concentrations of 25%-30% should last up to eight hours.

A safer, low-absorption type of DEET developed by Sawyer products has been accepted for general use by the EPA. In a study done by the Coulston Foundation in 1999, one application of Sawyer’s Controlled Release DEET Low Absorption Formula was compared to one application of a comparable DEET concentration in an alcohol base. The Sawyer technology, which slows the release of DEET into the body, was found to inhibit its absorption by the skin; specifically only 6.6% of Sawyer’s DEET formula was absorbed in the skin compared to 16.3% of the alcohol-based DEET formula. This product is sold at REI and other camping supply shops, and may be used with sunscreen, though it is recommended to apply sunscreen before the repellent.

For added protection, spray repellent in living and sleeping areas and soak mosquito nets and clothing in Permethrin (not for use on human skin, but a safe liquid repellent effective through several washings). Clothing and other material must be soaked in Permethin several days before travel to allow them time to dry. 

Tropical Photography of Anopheles Habitat by Elliot Stein

Chemoprophylaxis – Illness Prevention

Chemoprophylxis is most effective when prescribed with consideration of the traveler’s destinations. The popular drugs Mefloquine and Chloroquine are both taken weekly prior to, during, and after exposure, and their taste can be masked by food or drink for fussy children. Dr. Fisher says they are considered safe in the proper dosage, approximately 5mg per kilo of body weight, but advises parents to store them carefully and watch for any adverse side effects.

Doxycycline is an alternative used in countries where other medications have lost their effectiveness, however, it must be taken daily, may discolor the teeth, and cannot be given to children under eight years old. Malarone is another antimalarial medication approved for use by adults and children by the US Food and Drug Administration, and only has to be taken an additional seven days after travelling rather than four weeks. A study published in the October 2001 issue of Clinical Infectious Diseases showed that Malarone was better tolerated than Mefloquine, therefore causing more patients to complete the course of the medication. The drug Primaquine is most effective at preventing malaria spread by P. vivax, the parasite that most frequently causes malaria, and so is a good choice for people travelling in countries where malaria is caused more than 90% by P. vivax. Dr. Fisher says that other preventative drugs such as Atovaquone and Proguanil have proven effective in travelers over 11 kgs in weight, and notes that several other drugs being tested may provide safer alternatives in the future.

Nursing mothers taking malaria preventatives should note that the small amounts contained in breast milk are not enough to hurt an infant, nor to preclude her from needing her own antimalarial medication, although Primaquine specifically should not be used by pregnant or breastfreeding women.

Early Detection – Immediate Therapy

If you or your children display any malarial symptoms, you should be examined immediately. Symptoms may appear seven days to several months after exposure, because preventive medication can delay their appearance. Malarial symptoms include fever, chills, nausea and vomiting, body aches, and general malaise. To be on the safe side, all fevers and flu symptoms should be assessed promptly. Though three of the four strains of malaria are normally non-fatal, all are particularly serious illnesses for the very young and very old.

Consult with your physician and pediatrician four to six weeks before travel to find out what shots and prescriptions your family needs, and you’ll have time to try out prescribed preventive drugs and repellents for possible reactions or side effects. 

With some simple precautions, you can greatly reduce malaria risk and enhance the outdoor fun on your next tropical adventure.

Compiled from research presented at the 2003 Pediatric Vaccine Seminar of the International Society of Travel Medicine with current materials published by the Centers for Disease Control Division of Quarantine and the World Health Organization. Contact your pediatrician or call the CDC Information Hotline at 1-800/232-4636 for the latest information.

Tropical Photography of Anopheles Habitat by Elliot Stein