Perspectives: Malaria in Long-Term Travelers & Expatriates
Perspectives: Malaria in Long-Term Travelers & Expatriates
Long-term travelers and expatriates in malarious areas are at risk for severe malaria throughout their stay, but sometimes they do not recognize the continued need for reducing risk through prophylaxis and personal protective measures. Even those with knowledge of the need for preventive practices may be unable to adhere to them or may opt to discontinue them. Guidelines for malaria prevention might be interpreted as focusing on preventing Plasmodium falciparum malaria in short-term travelers. Optimal malaria prevention in long-term travelers poses dilemmas because of diverse traveler characteristics and itineraries (including traveling in and out of malarious areas), the heterogeneous quality of and access to medical care, and the limited reports on long-term safety and efficacy of antimalarial drugs. Moreover, parasite resistance, seasonality, and the intensity of transmission evolve with environmental and population alterations.
For this discussion, long-term travelers are defined as nonimmune travelers staying in malaria-endemic countries for ≥6 months. A review summarized published data on the risk of malaria in long-term travelers, evidence for personal protective measures, and safety and tolerability of malaria prophylaxis during long-term use (Box 8-5).
Box 8-5. Key findings from a review of studies relevant to long-term travelers and expatriates 1
- Long-term travelers are at higher risk for malaria than short-term travelers.
- Long-term travelers underuse personal protective measures and often abandon continuous prophylaxis.
- Travelers use a variety of unproven strategies during long stays: discontinuing prophylaxis after the initial period of stay, using different medications for prophylaxis in succession, relying on standby emergency self-treatment, or taking prophylaxis intermittently during high-transmission periods or locations.
- All the prophylaxis strategies have advantages and disadvantages, but prophylaxis is recommended for at least high-transmission destinations and seasons. People who elect to take prophylaxis only for high-transmission destinations and seasons should ensure they have access to a reliable supply of a full course of an approved malaria treatment regimen (Box 3-3 and Table 3-8).
- Poor-quality drugs (including antimalarial drugs) threaten the health of long-term travelers who obtain their medications in developing countries.
- Primaquine (in people with adequate levels of G6PD) can be used as presumptive antirelapse therapy after long exposures in areas with high Plasmodium vivax prevalence.
1 Adapted from: Chen LH, Wilson ME, Schlagenhauf P. Prevention of malaria in long-term travelers. JAMA. 2006;296(18):2234–44.
Individualized risk considerations
Some travelers have preconceived notions about malaria prevention for their long-term journey or stay in an endemic region that may shape their acceptance of standard recommendations. Even when educational efforts appear successful in convincing such travelers to take prophylaxis, they often meet other travelers or locals who convince them that the medication is either not necessary or is in some way detrimental to their health. Additionally, adherence to malaria prophylaxis among Peace Corps volunteers was associated with forgetting the medication, fear of long-term adverse effects, and experiencing adverse events attributed to the drug. Nonetheless, taking a detailed assessment of the traveler’s risk and attitude may help the clinician determine the traveler’s likelihood of adherence to preventive actions during long-term travel. Consider asking about the following:
- Traveler’s beliefs regarding personal protective measures
- Traveler’s knowledge and preferences toward continuous prophylaxis
- Travel characteristics, including the quality of accommodations, activities, and social support and network
- Economic considerations
- Destination-specific infrastructure, including medical service, access to high-quality care, medication supply, and availability of repellents, insecticides, and nets
Personal Protective Measures
Preventing malaria in all travelers is a complex issue and particularly so for long-term travelers and expatriates, who require personalized expert advice. For long-term travelers and expatriates, malaria prevention must stress the role of personal protective measures as an adjunct to prophylaxis, including adapting behaviors to minimize mosquito exposure, staying in housing with screened windows and doors, using air conditioning, sleeping under an insecticide-treated bed net, applying insecticide sprays in the residence, managing the environment to reduce vector breeding, using effective repellent, and wearing long sleeves and pants when practical (Box 8-6).
Box 8-6. Practical advice on personal protective measures for clinicians counseling long-term travelers and expatriates
- Instruct on treating clothing and bed nets with a pyrethroid insecticide.
- Discuss the effectiveness of applying repellent.
- Review experience regarding efficacy and safety of repellents: in >60 years since DEET came into wide use, no adverse effects attributed to long-term use have been published.
- Discuss mosquito-proofing methods for use in accommodations, including maintenance of drains, elimination of mosquito breeding sites, installation of screens, and applying insecticide indoors.
- Advise on the biting habits of the local Anopheles mosquito populations.
Prophylaxis decreases the risk of illness, hospitalization, and death. However, some travelers may disregard prophylaxis recommendations. Working with the traveler to overcome his or her concerns, providing insight into the severity of malaria, and deriving a feasible and sensible prophylaxis plan are recommended (Box 8-7). For example, a long-term traveler or expatriate based in a malaria-endemic country with highly seasonal or geographically focal malaria transmission may rely primarily on personal protective measures at some times and target periods of prophylaxis during the transmission season or when venturing into endemic areas. However, a traveler who will be staying in an area of high continuous malaria transmission should continue to use malaria prophylaxis for the entire stay.
Another scenario that may arise and merits discussion with long-term travelers is whether they should continue malaria prophylaxis if they develop fever during travel. Rapid diagnostic tests are unreliable for self-diagnosis in travelers because most travelers are not able to use and read the test correctly. (In the United States, rapid diagnostic tests are only approved for laboratory use.) Because fever has numerous possible causes besides malaria, travelers should continue their recommended prophylaxis provided that they are tolerating it well. In addition, they should be tested for malaria even if taking prophylaxis. Clearly the possibility of other treatable causes of fever should be explored. Travelers who will be >24 hours from adequate medical care should consider carrying a full course of malaria medication for emergency self-treatment when malaria is suspected, regardless of whether they take continuous prophylaxis. Travelers who might self-administer treatment should be told that they still require follow-up care as soon as they are able to access it.
Unfortunately, in many countries malaria is a frequent diagnosis in people who do not have malaria. In addition to receiving unnecessary treatment, long-term travelers and expatriates who are misdiagnosed with malaria may stop taking their prophylaxis because they erroneously believe that it did not work. It is difficult to relay such a concept during the pretravel consult, but the attempt should be made.
Box 8-7. Practical advice on malaria prophylaxis for long-term travelers and expatriates
- Reassure travelers that long-term use of prophylaxis is safe and effective.
- Chloroquine used long-term (5–6 years of weekly dosing) raises concern for retinal toxicity. A baseline ophthalmologic examination is recommended, with follow-up every 6–12 months after 5 years of use.
- Encourage travelers to take their prophylaxis for as long as they are living in areas with malaria transmission.
- For people living in countries with only seasonal or focal areas of malaria transmission, use prophylaxis during high-transmission seasons or for travel to endemic areas.
- Assess whether traveler should carry a reliable supply of malaria treatment medication. If malaria is diagnosed, the traveler will have an effective medicine that will not interact with other medicines (see Chapter 3, Malaria).
- Beware of the wide availability of poor-quality (substandard, falsified, or counterfeit) antimalarial drugs, especially in Asia and sub-Saharan Africa. All medications should be obtained from the home country or a reliable and reputable local source.
- Discuss Plasmodium vivax malaria with travelers who may have prolonged exposure in high-prevalence areas (for example, a traveler who has been in Papua New Guinea for 6 months).
- Check G6PD to determine whether an expatriate can take presumptive antirelapse therapy after leaving an endemic area.
Recommendations for malaria prevention in all travelers must be personalized. Tailoring advice by assessing the traveler’s preferences and concerns and determining the traveler’s possible adherence, along with education regarding malaria, will likely result in better adherence than simply prescribing a course of prophylaxis. The following messages should be conveyed to the long-term traveler regarding malaria prevention:
- Adherence to prophylaxis in high-risk areas is essential.
- Use of personal protective measures, such as bed nets and screens, is critical (as many will not use repellents long term).
- Reliable medical facilities at the destination should be located as soon as feasible.
- Data support the safety of long-term use of prophylaxis.
- Supplies of antimalarial drugs should be brought from home, because poor-quality drugs (substandard, falsified, or counterfeit) are prevalent in malaria-endemic countries.
- Fever is a worrisome sign, and malaria must be considered and ruled out (see Chapter 5, Fever in Returned Travelers).
- A medical evacuation insurance policy should be purchased if the traveler will be in an area with inadequate medical facilities.
- Although individual use of rapid diagnostic tests is not advised, carrying standby treatment with follow-up medical care may be appropriate for some.
- Presumptive antirelapse therapy may be appropriate for exposure in areas with intense P. vivax transmission (after a normal level of G6PD is documented).
- Misconceptions regarding malaria are pervasive in malaria-endemic countries among expatriates and local residents, and long-term travelers should trust health advice only from reputable and respected sources.
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Lin H. Chen
Perspectives sections are written as editorial discussions aiming to add depth and clinical perspective to the official recommendations contained in the book. The views and opinions expressed in this section are those of the author and do not necessarily represent the official position of CDC.