JOURNAL OF GYNECOLOGIC SURGERY© Mary Ann Liebert, Inc.

Infection Risks of Travelers: Malaria

NEWTON G. OSBORNE, M.D., Ph.D.

RECENT REPORTS from the Occupational Health and Safety Administration (OSHA) suggest that Amer-ican women are traveling to exotic destinations more than their grandmothers and even their mothers

did a generation ago. International travel has risen steadily over the years. Business travel accounts for ap-proximately one third of all international travel. Travel to certain destinations expose individuals to infec-tious agents against which they may have no immunity or adequate prophylaxis. It is therefore advisablethat all international travelers obtain specific health information about the countries or regions they intendto visit and to be aware of the preventive health measures that are available for such regions.

Travelers are at risk of infection with malarial parasites, poliovirus, hepatitis A virus, hepatitis B virus(HBV), and hepatitis C virus, and are at risk for acquiring typhoid fever, cholera, yellow fever, encephali-tis, rabies, Chagas disease, or other waterborne, airboren, or arthropod-borne diseases. Fortunately, diseasessuch as malaria, yellow fever, poliomyelitis, and hepatitis, can be prevented easily either by taking pro-phylactic measures or by getting proper vaccinations prior to travel.

Malaria can be a particularly dangerous illness in susceptible individuals, especially if it progresses tocerebral malaria. Symptoms that are commonly seen with uncomplicated malaria include recurrent fever,weakness, vomiting, diarrhea, and cough. Impaired consciousness, seizures, or coma that was preceded bysymptoms of malaria would suggest cerebral malaria. According to the World Health Organization defini-tion,1 cerebral malaria is present in a patient who cannot localize a painful stimulus, has peripheral asex-ual Plasmodium falciparum parasitemia, and has no other identifiable causes of encephalopathy. The pres-ence of retinal hemorrhages and of papilledema are ominous signs.

The differential diagnosis in a traveler to an endemic area for malaria who develops signs of meningitisand/or encephalitis includes infections with viral or bacterial organisms, besides cerebral malaria. The pleo-cytosis seen with viral or bacterial meningitis and/or encephalitis, allows clinicians to rule viruses and bac-teria in or out as etiologic agents. Travelers to endemic areas for malaria who develop classical symptomsare much more likely to have cerebral malaria than viral or bacterial encephalopathy.

Cerebral malaria is associated with hyperparasitemia. In nonimmune persons, such as travelers from theUnited States are likely to be, even low levels of parasitemia may be accompanied by severe illness. Em-piric antimalarial treatment may be necessary when results of blood smears are negative in individuals whohave previously received antimalarial medication. Parasite mRNA or a DNA polymerase chain reaction canbe used to confirm a presumptive diagnosis of malaria on a returning visitor from an endemic area.2 Thesetests are more sensitive than microscopy and allow identification of the parasite’s species strain.

There are several preventive measures that travelers can take to reduce the risk of acquiring malaria whiletraveling. Doxycycline, taken daily (100 mg orally bid), can be used prophylactically to reduce the risk ofmalaria significantly. In addition, insecticide-treated nets over the bed while sleeping, especially if com-bined with permethrin-treated fabric (clothing and sheets) have been shown to reduce the risk of acquiringmalaria significantly. Travelers to endemic areas should also consider wearing trousers and long-sleevedshirts routinely, in spite of the heat and humidity that is common in areas where malaria is endemic.

Another antimalarial medication that can be used effectively as a prophylactic against malaria is meflo-quine hydrochloride. Mefloquine is a derivative of 4-quinoline-methanol. It acts as a blood schizonticide.It is effective against chloroquine-resistant P. falciparum. Prophylaxis should begin 1 week before depar-

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Howard University College of Medicine, Washington, DC.

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ture to the endemic area. The dosage is 250 mg weekly, to be taken with food and with at least 240 mL (8 ounces) of water. The drug should be taken on the same day every week and continued for 4 additionalweeks after leaving the endemic area.

It is important to be aware that if a traveler acquires malaria with Plasmodium vivax and is treated withmefloquine, there is a high risk of relapse because mefloquine does not eliminate extraerythrocytic (i.e., he-patic) parasites. These patients should subsequently be treated with an 8-aminoquinoline such as primaquine.

Other prophylactic regimens include atovaquone plus proguanil, chloroquine (not recommended as soleagent for areas known to harbor choroquine-resistant P. falciparum), and sulfadoxine plus pyrimethamine.Chloroquine may be combined with proguanil or with other antimalarials if there is a concern for resis-tance.

To reduce the risk of other infections, travelers should avoid drinking tap water, fountain drinks, bever-ages cooled in icy water, and the use of ice cubes in their drinks. Travelers should only drink bottled, boiled,or carbonated drinks from sealed cans or bottles.

The Centers for Disease Control and Prevention (CDC), the U.S. Department of State, and the Interna-tional Society of Travel Medicine have comprehensive information Web sites for prospective travelers. Theycan be accessed at the following:

www.cdc.gov/travel (CDC)http://travel.state.gov (U.S. Department of State)www.istm.org (The International Society for Travel Medicine).

REFERENCES

1. World Health Organization, Communicable Diseases Cluster. Severe falciparum malaria. Trans R Soc Trop MedHyg 2000;94(suppl. 1):S1–S90.

2. Farnert A, Arez AP, Babiker HA, et al. Genotyping of Plasmodium falciparum infections by PCR: A comparativemulticentre study. Trans R Soc Trop Med Hyg 2001;95:225–232.

Address reprint requests to:Newton G. Osborne, M.D., Ph.D.

Department of Obstetrics/GynecologyHoward University College of Medicine

2041 Georgia Avenue NWWashington, DC 20060

E-mail: NewtonOsborne@aol.com

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