ARCHIVED - Supplement: Canadian Recommendations for the Prevention and Treatment of Malaria Among International Travellers

 

3. Prevention - Malaria Education for Travellers

Enhancing adherence to antimalarial chemoprophylaxis and personal protective measures

Adherence to antimalarial prophylactic drug regimens and use of personal protective measures are essential to the prevention of malaria. Most deaths in Canadian travellers due to malaria occur in those who did not take antimalarial medications or who took ineffective medications not recommended by CATMAT (6, 8, 24).

Unfortunately, the evidence demonstrates that nonadherence to malaria prevention recommendations is common and ranges from 30% to 55% of travellers (25, 26, 27, 28, 29). Non-adherence has even been reported in travelling physicians: less than half of general practitioners practising in the UK who travelled to South Asia admitted to full compliance with malaria prevention practices (28). Non-adherence to malaria chemoprophylaxis is prevalent among backpacking travellers; immigrants who return to their country of origin to visit friends and relatives; long-term (greater than 1 month) travellers; those who irregularly use insect personal protection measures; travellers less than 40 years; and those given daily dosing schedules (25, 26, 27, 28, 29, 30, 31, 32).

Reasons given for non-adherence are varied and include false beliefs that the travel destination is malaria-free; fear of or past experience with medication side effects; false beliefs in long-term immunity to malaria acquired from prior infections; cost of medications; confusion arising from alternative recommendations; forgetfulness; or no interest in taking antimalarial medications with no specific reason given (25, 26, 27, 29-32).

There are no published data on approaches to improve adherence to malaria prevention practices. Recognizing the type of traveller who is most likely to be non-adherent, as well as the reasons why travellers may become non-adherent, may assist with pre-travel health counselling (33). Published reasons for non-adherence should form part of the pre-travel health discussion with all travellers seeking malaria prevention advice. If there are concerns about a traveller's ability to tolerate a particular antimalarial prophylactic regimen, malaria chemoprophylaxis may be initiated in advance of travel to assess drug tolerance.

Well-informed health care providers are essential to providing accurate information for travellers; however, family physicians may not provide correct advice (24, 34, 35, 36). Travellers using only one information source (such as a family physician) are significantly more compliant than those consulting the differing recommendations available from different sources (35).

Early diagnosis and treatment

All travellers must be informed that malaria should be suspected if unexplained fever occurs during or after travel. Medical attention should be sought as soon as possible, and the traveller should request that a thick and thin blood film be immediately obtained and examined for malaria parasites. If the initial blood film is negative and the traveller remains symptomatic, then the blood film should be repeated in 12 to 24 hours. The most important factors that determine the survival of patients with P. Falciparum malaria are early diagnosis and prompt initiation of appropriate treatment (8).

Evidence-based medicine recommendations EBM rating
Increased education of travellers who traditionally are the least compliant with malaria chemoprophylaxis is recommended (backpacking travellers, immigrants who return to their country of origin to visit friends and relatives, long-term travellers [greater than one month], travellers less than 40 years of age) (25, 26, 28, 30, 31, 32, 33). B II
If there are concerns about a traveller's ability to tolerate a particular antimalarial prophylactic regimen, malaria chemoprophylaxis can be initiated in advance of travel to assess drug tolerance. C III
A traveller must be informed that survival of patients with P. Falciparum malaria is determined by early diagnosis and prompt initiation of appropriate treatment (8). A II

Insect Repellants and Clothing

All travellers to areas with malaria risk are advised to use personal protective measures to prevent bites from Anopheles mosquitoes. This subject has been covered in a previous CATMAT Statement (37), and much of the following is taken directly from this source.

Protection from mosquito bites can reasonably include alteration of the travel itinerary to limit time spent in malarial regions as well as to avoid outdoor activities during and after dusk and before dawn. All travellers to areas with malaria risk are advised to use personal protective measures to prevent bites from Anopheles mosquitoes. Use of effective repellents and insecticide-treated clothing, covering up exposed skin and avoidance of areas or times where/when vectors are active are also considered to be important for prevention of malaria (38, 39).

DEET (N,N-diethyl-3-methyl-benzamide, also known as N,N-diethyl-m-toluamide) remains the first choice among repellants. Canadian recommendations for domestic use of 10% DEET or less for children < 12 years emphasize the need for frequent re-applications because of the relatively short duration of protection (40). For protection from malaria-bearing Anopheles, CATMAT recommends up to 30% DEET-containing products for all age groups. Extended-duration DEET formulations have useful advantages over other formulations and are preferred (41, 42). Where extended-duration formulations are unavailable, products that contain up to 35% DEET are preferred. DEET and sunscreen combination products are not recommended (43); however, if DEET and sunscreen application are both required, apply the sunscreen first, allowing skin penetration for 20 minutes, followed by DEET application (Canadian Dermatology Association). Consider P-menthane-3,8-diol (lemon eucalyptus oil) as a second-line alternative repellent if DEET use is not possible (e.g., for persons allergic to DEET) (44). Consider soybean oil 2% “blocker” repellents as a third-line repellent where arthropod-borne infections present a significant risk (38, 45). Picaridin (Bayrepel, KBR 3023, Autan), which is available in Europe and the United States and recommended by the WHO, may be as effective as 15% to 50% DEET (46, 47). Repellents containing citronella oil are not effective (38).

There are several other ineffective insect personal protection measures, which are not recommended (37):

  • electronic (ultrasonic) devices
  • wristbands, neckbands and ankle bands impregnated with repellents
  • electrocuting devices (“bug zappers”)
  • odour-baited mosquito traps
  • citrosa plant (geranium houseplant)
  • orally administered vitamin B1
  • skin moisturizers that do not contain an approved active repellent.

Insecticide-Treated Bednets

Given the behaviour of malaria vectors (usually night-active), the proper use of insecticide-treated bednets (ITNs) is a critical personal protective measure for malaria (48, 49), and insecticide (permethrin)- impregnated clothing should be considered(50). Insecticide-impregnated mosquito netting substantially increases the protection afforded by the net (48,50), since arthropods may still bite through the mesh when the traveller's skin is against it or even pass through the net if they are small enough. The mosquito net should be intact (without tears or large holes), and tucked in under a mattress. The period of effectiveness of pyrethroid-impregnated nets varies from 6 to 12 months, depending on the product used and on the number of launderings (37).

Pyrethroid treatments for bednets are not currently available in Canada but can be obtained from the United States or in several malaria-endemic destinations (such as sub-Saharan African countries). In recent years, long lasting insecticide-treated bednets with durations of efficacy of up to 5 years have become available in sub-Saharan Africa (51).

Pyrethroid-treated netting may be used for more than just beds (e.g., over strollers, playpens and cradles) to protect the very young from mosquito bites. For all children travelling to malarial regions, particular attention should be paid to other personal protective measures, such as protective and permethrin-treated clothing as well as effective insect repellents (37).

 

Evidence-based medicine recommendations EBM rating

Measures for all travellers who are at risk of exposure to arthropod-borne infections

  • Minimize entry of mosquitoes into work and accommodation areas: place screens on windows, check to ensure that doors are in good repair and closed properly and tightly, and that the walls and the roof are “without holes”.
  • Stay in a mosquito-protected area during the time(s) of day when local mosquitoes are actively biting.
  • Avoid travelling to a locale during the season that is most strongly (or only) associated with transmission of malaria.
  • Sleep under insecticide (pyrethroid)-impregnated mosquito nets (in areas where insects cannot be excluded from sleeping area) (48, 50).
  • Consider wearing insecticide (permethrin)-impregnated clothing (52).
B II
Insecticide (e.g., permethrin)-impregnated mosquito netting substantially increases the protection afforded by the net (48). A I

Physical barriers for all travellers who are at risk of exposure to arthropod-borne infections.

  • Wear long-sleeved shirts (sleeves down, buttoned or zipped, tucked into pants) and long pants (tucked into socks or footwear) to inhibit or prevent mosquito bites.
  • Dress in light-coloured clothing, which may ward off mosquitoes (53).
  • Sleep under a mosquito net that is intact (without tears or large holes), tucked in under a mattress.
B II
All travellers at risk of exposure to serious arthropod-borne infections should appropriately use insect repellent containing DEET (38), the preferred insect repellent, unless contraindicated (e.g., allergic reaction). A I

Alternative personal protective measures for children:

  • Use insecticide-impregnated mosquito nets as the first line of defence, especially for infants aged < 6 months.
  • Use portable mosquito nets, including the self-standing type, placed over a car seat, a crib, playpen or stroller, providing an insect-protected environment for infants.
  • Consider the judicious use of DEET for children of any age as a complement to the other methods of protection (54).
A II
Extended duration DEET formulations have useful advantages over other formulations and, overall, are preferred (41). If these formulations are unavailable, products that contain up to 35% DEET are preferred. B I
DEET and sunscreen combination products are not recommended (43); however, if DEET and sunscreen application are both required, apply the sunscreen first, allowing skin penetration for 20 minutes, followed by DEET application (55). A II
Avoid using repellents containing citronella oil (38). E II
Consider P-menthane-3,8-diol (lemon eucalyptus oil) as a second-line alternative repellent, if DEET use is not possible (e.g., persons allergic to DEET) (44). A II
Consider soybean oil 2% “blocker” repellents as a third-line repellent where arthropod-borne infections present a significant risk (38). A II
Picaridin (Bayrepel, KBR 3023, Autan), may be as effective as 15% to 50% DEET (46, 47); however, it is not registered for use in Canada but is available in Europe and the United States. A II

Ineffective insect personal protection measures that are not recommended (37):

  • electronic (ultrasonic) devices
  • wristbands, neckbands and ankle bands impregnated with repellents
  • electrocuting devices (“bug zappers”)
  • odour-baited mosquito traps
  • citrosa plant (geranium houseplant)
  • orally administered vitamin B1
  • skin moisturizers that do not contain an approved active repellent.
E II

 

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