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Another Risk to US Travelers—Malaria

Clinician Reviews. 2014 November;24(11):E1-E7

References

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INDIVIDUALIZING PREVENTION DIRECTIVES
The mainstays of malaria prevention include nonpharmacologic and behavioral interventions, as well as chemoprophylaxis. Most cases of malaria in travelers returning to the United States result from the improper implementation of prophylactic measures.³Discussing individual risk with travelers is an easy way to bolster adherence to malaria prevention measures, and some evidence suggests it is effective¹⁰(strength of recommendation [SOR]: C). Other limited studies have also shown that malaria education can improve knowledge about malaria transmission and increase the likelihood that preventive measures will be used.^11,12

Recommend nonpharmacologic measures even for those using chemoprophylaxis
Nonpharmacologic interventions such as sleeping under permethrin-treated bednets, wearing long sleeves and full-length pants, treating clothes with permethrin, and applying DEET (N,N-diethyl-meta-toluamide) to exposed skin are effective and have the added benefit of preventing non-malarial arthropod-borne diseases⁴(SOR: B). Studies have shown that, compared with sleeping without nets, the use of insecticide treated-nets can reduce child mortality by 17% and the incidence of uncomplicated malarial episodes by 50%.¹³In areas with malaria transmission, 10% to 30% DEET—used alone or in combination with permethrin-treated clothing— can reduce bite load, although the American Academy of Pediatrics recommends against using DEET in children younger than 2 months of age.^14,15

Using these measures in combination from dusk to dawn, when Anopheles mosquitoes are active, has been shown to be effective, although randomized, controlled studies are lacking.¹⁶Remaining indoors during these peak biting periods is also advisable. In certain areas, and with the right itinerary, the traveler may only need to employ nonpharmacologic methods of preventing malarial infection. Recommend them to all patients traveling to malarial regions, even to individuals using pharmacologic prophylaxis.

Factors determining the need for,  and selection of, chemoprophylaxis 
When used properly, chemoprophylactic drugs are effective in preventing malaria (SOR: A). Atovaquone-proguanil achieves efficacy of 95% to 100%,¹⁷while doxycycline, primaquine, and mefloquine are slightly less effective.^18-20Chloroquine is effective in 6 regions of the tropics and subtropics where Plasmodium falciparum resistance has not developed. Select a drug based on your assessment of an individual’s level of risk according to the personal itinerary, trip duration and accommodations, cost of medication, tolerance for adverse effects, and other factors (eg, comorbidities, concurrent drug usage, pregnancy).

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