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Chapter 8Advising Travelers With Specific Needs

Perspectives: Malaria in Long-Term Travelers & Expatriates

Lin H. Chen

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 chemoprophylaxis and personal protective measures. 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 recent review summarized published data on the risk of malaria in long-term travelers, evidence for personal protective measures, and safety and tolerability of malaria chemoprophylaxis during long-term use (Box 8-03).

Box 8-03. Key findings from a review of studies relevant to long-term travelers and expatriates1

  • Long-term travelers are at higher risk for malaria than are short-term travelers.
  • Long-term travelers underuse personal protective measures and often abandon continuous chemoprophylaxis.
  • Travelers use a variety of incorrect or unproven strategies during long stays: discontinuing chemoprophylaxis after the initial period of stay, using different medications for chemoprophylaxis in succession, relying on standby emergency self-treatment, or taking chemoprophylaxis intermittently during high-transmission periods or locations.
  • All the chemoprophylaxis strategies have advantages and disadvantages, but chemoprophylaxis is recommended for the duration of the stay.
  • Counterfeit 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 glucose-6-phosphate dehydrogenase) can be used as presumptive antirelapse therapy after long exposures in areas with high Plasmodium vivax prevalence.

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 chemoprophylaxis, 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. Nonetheless, assessing their risk may help determine a traveler’s likelihood of adherence to preventive actions during long-term travel:

  • Traveler’s beliefs and practices regarding personal protective measures
  • Traveler’s knowledge and preferences toward continuous chemoprophylaxis
  • 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

PRACTICAL RECOMMENDATIONS

Personal Protective Measures

Preventing malaria in all travelers is a complex issue and requires personalized expert advice. For long-term travelers, malaria prevention must stress the role of personal protective measures as an adjunct to chemoprophylaxis, 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 8-04).

Malaria Chemoprophylaxis

Chemoprophylaxis decreases the risk of illness, hospitalization, and death. However, some travelers may disregard chemoprophylaxis recommendations. Working with the traveler to overcome his or her concerns, providing insight into the severity of malaria, and deriving a feasible and sensible chemoprophylaxis plan are recommended (Box 8-05). 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 chemoprophylaxis during the transmission season or when venturing into endemic areas. However, a traveler who will be residing in an area of continuous malaria transmission should continue to use malaria chemoprophylaxis for the entire stay.

Another scenario that may arise and merits discussion with long-term travelers is whether they should continue malaria chemoprophylaxis 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. (Rapid diagnostic tests are also not sold to the general public in the United States.) Because fever has numerous possible causes besides malaria, travelers should continue their recommended chemoprophylaxis provided that they are tolerating it well. In addition, they should be tested for malaria, even if taking prophylaxis. Obviously, the possibility of other treatable causes of fever should be explored. However, in addition to continuing chemoprophylaxis, some travelers who will be >24 hours from adequate medical care may be prescribed a full course of malaria medication for emergency self-treatment when malaria is suspected. 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 who are misdiagnosed with malaria may stop taking their chemoprophylaxis because they erroneously believe that it did not work. It is difficult to relay such a concept during the pre-travel consult, but the attempt should be made.

Box 8-04. 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.

Box 8-05. Practical advice on malaria chemoprophylaxis for long-term travelers and expatriates

  • Reassure travelers that long-term use of chemoprophylaxis 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 chemoprophylaxis 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 chemoprophylaxis 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 counterfeit and substandard 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 glucose-6-phosphate dehydrogenase to determine whether an expatriate can take presumptive antirelapse therapy after leaving an endemic area.

SUMMARY

Recommendations for malaria prevention in all travelers must be personalized. Tailoring advice by assessing the traveler’s preferences and determining the traveler’s possible adherence, along with education regarding malaria, will likely result in better adherence than simply prescribing a course of chemoprophylaxis. The following messages should be conveyed to the long-term traveler regarding malaria prevention:

  • Adherence to chemoprophylaxis 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 chemoprophylaxis.
  • Supplies of antimalarial drugs should be brought from home, because counterfeit and poor-quality drugs 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 glucose-6-phosphate dehydrogenase 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.

BIBLIOGRAPHY

  1. Askling HH, Nilsson J, Tegnell A, Janzon R, Ekdahl K. Malaria risk in travelers. Emerg Infect Dis. 2005 Mar;11(3):436–41.
  2. Berg J, Visser LG. Expatriate chemoprophylaxis use and compliance: past, present and future from an occupational health perspective. J Travel Med. 2007 Sep–Oct;14(5):357–8.
  3. Chen LH, Wilson ME, Davis X, Loutan L, Schwartz E, Keystone J, et al. Illness in long-term travelers visiting GeoSentinel clinics. Emerg Infect Dis. 2009 Nov;15(11):1773–82.
  4. Chen LH, Wilson ME, Schlagenhauf P. Controversies and misconceptions in malaria chemoprophylaxis for travelers. JAMA. 2007 May 23;297(20):2251–63.
  5. Keiser J, Singer BH, Utzinger J. Reducing the burden of malaria in different eco-epidemiological settings with environmental management: a systematic review. Lancet Infect Dis. 2005 Nov;5(11):695–708.
  6. Leder K, Black J, O’Brien D, Greenwood Z, Kain KC, Schwartz E, et al. Malaria in travelers: a review of the GeoSentinel surveillance network. Clin Infect Dis. 2004 Oct 15;39(8):1104–12.
  7. Lengeler C. Insecticide-treated bed nets and curtains for preventing malaria. Cochrane Database Syst Rev. 2004(2):CD000363.
  8. Newton PN, Green MD, Fernandez FM, Day NP, White NJ. Counterfeit anti-infective drugs. Lancet Infect Dis. 2006 Sep;6(9):602–13.
  9. Pluess B, Tanser FC, Lengeler C, Sharp BL. Indoor residual spraying for preventing malaria. Cochrane Database Syst Rev. 2010(4):CD006657.
  10. Toovey S, Moerman F, van Gompel A. Special infectious disease risks of expatriates and long-term travelers in tropical countries. Part I: malaria. J Travel Med. 2007 Jan–Feb;14(1):42–9.
 
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