Chapter 3 – Prevention-Bite protection measures and malaria education: Canadian recommendations for the prevention and treatment of malaria

• Previous Page
• Table of Contents
• Next Page

An Advisory Committee Statement (ACS) from the
Committee to Advise on Tropical Medicine and Travel (CATMAT)

Updated 2017

Table of contents

• Preamble
• Background
• Methods
• Results
• Values and preferences
• Adherence – the achilles’ heel of malaria prevention
• Education
• Prevention - personal protective measures
• Recommendations
• Acknowledgements
• References
• Appendices

Preamble

The Committee to Advise on Tropical Medicine and Travel (CATMAT) provides the Public Health Agency of Canada (PHAC) with ongoing and timely medical, scientific, and public health advice relating to tropical infectious disease and health risks associated with international travel. PHAC acknowledges that the advice and recommendations set out in this statement are based upon the best current available scientific knowledge and medical practices, and is disseminating this document for information purposes to both travellers and the medical community caring for travellers.

Persons administering or using drugs, vaccines, or other products should also be aware of the contents of the product monograph(s) or other similarly approved standards or instructions for use. Recommendations for use and other information set out herein may differ from that set out in the product monograph(s) or other similarly approved standards or instructions for use by the licensed manufacturer(s). Manufacturers have sought approval and provided evidence as to the safety and efficacy of their products only when used in accordance with the product monographs or other similarly approved standards or instructions for use.

Box 1: Advice for travellers

Background

There are a number of safe and efficacious interventions that can be used by travellers to reduce the risk of developing malaria. Their utility, however, is constrained by suboptimal adherence. This chapter discusses education as relates to prevention of malaria, and the values and preferences of travellers that may influence their adherence to preventive measures. It also provides an overview of personal protective measures (PPM) for protection against mosquito bites. More detailed recommendations for PPM are available in the Committee to Advise on Tropical Medicine and Travel (CATMAT)’s Statement on Personal Protective Measures to Prevent Arthropod Bites^{Reference 1}.

Methods

General

This chapter of the CATMAT malaria guidelines was developed by a working group comprised of volunteers from the CATMAT committee. Criteria outlined in the CATMAT Statement on Evidence based process for developing travel and tropical medicine related guidelines and recommendations^{Reference 2}, were used to decide whether a Grading of Recommendations, Assessment, Development and Evaluation (GRADE) methodological approach would be required for this chapter. Malaria education and bite protection interventions utilize approaches that: have no sensible alternative (e.g., it makes no sense to advise travellers not to use bite prevention interventions where such are indicated); and/or, present little or no risk of harm with the potential for substantial benefit (e.g., use of bed nets and repellents to prevent bites). Additionally, and for bite protection specifically, CATMAT already has reviewed the evidence and published a guideline^{Reference 1}. We do not believe that the effort required to apply GRADE in these circumstances is worth its potential payoff; therefore, the committee chose to develop recommendations without GRADE or to base them on existing guidelines (i.e. bite prevention methods). While prudent from the perspective of making best use of limited resources, this decision reduces our ability to make quantitative estimates of harms and benefits, e.g., absolute benefit of an intervention or numbers needed to treat to prevent a case of malaria.

The working group, with support from the secretariat, was responsible for: literature retrieval, synthesis and analysis; development of key questions and draft recommendations; and chapter writing. Based on the evidence compiled as well as expert opinion, recommendations for interventions were made and are summarized in table 3.1.

Systematic literature search

We identified, through committee discussion and consensus, a single key question for which a systematic literature review was undertaken:

• What are the values and preferences of travellers related to malaria prevention measures (e.g., bed nets, clothing, and window screens)?
• The following databases were searched for relevant evidence: Ovid MEDLINE, Embase, PubMed, Cochrane, and Scopus. The full search strategy is described in the appendix. Studies were included if (through review of abstracts): the target population(s) included travellers; the intervention(s) included individually-applied measures intended to prevent mosquitoes from biting (chemoprophylaxis was excluded); and, the interventions were intended to reduce exposure to malaria-infected mosquitoes. Evidence developed with/from residents of malaria endemic regions was excluded, as were factsheets, case studies or overviews targeting travellers and/or clinicians. We also used this systematic search to update evidence related to adherence to recommended malaria prevention practices.

Results

The systematic review yielded 83 studies. After removing duplicate records and screening titles and abstracts for relevance, we reviewed 34 full text articles for relevance. Most studies addressed knowledge, attitudes and practices (KAP) related to malaria prevention; however, they did not provide specific evidence related to the values and preferences of travellers for use of bite prevention measures against malaria. Ultimately only one study related to traveller values and preferences was retained.

Values and preferences

A single study^{Reference 3} that explicitly evaluated the values and preferences of travellers (in low or moderate risk areas) was identified. In this study, patients attending a clinic for a pre-travel consultation were provided with an opportunity to complete a self-administered questionnaire. As part of the assessment, each participant was provided with a decision aide that included information on the risk of malaria and the risk associated with use of preventive intervention. The decision aide is further described in a separate study^{Reference 4}. Patients also received information on costs associated with preventive approaches and were asked to select one of four options for malaria prevention (doing nothing was not included as an option). There was substantial heterogeneity in the choices made by patients, with 26% opting for bite prevention measures alone. While the quality of this evidence is very low (very high risk of bias, very high risk of indirectness^{Footnote a}), the study highlighted that the values and preferences of patients might be highly divergent regarding preferred approaches for malaria prevention for travel to low or moderate risk area^{Reference 3}. The implication is that informed travellers will make different choices for malaria prevention when risk is relatively modest.

Adherence – The Achilles’ heel of malaria prevention

Non-adherence to recommended malaria prevention practices is common^{Reference 5}, ^{Reference 6}, ^{Reference 7}, ^{Reference 8}, ^{Reference 9}, ^{Reference 10}, ^{Reference 11}, ^{Reference 12}, ^{Reference 13}, ^{Reference 14}, ^{Reference 15}, ^{Reference 16}, ^{Reference 17}. Certain groups seem to be at higher risk for non-adherence, for example: backpacking travellers; travellers who do not have an a priori intent to use such practices; travellers who are not concerned about malaria; immigrants who return to their country of origin to visit friends and relatives (VFRs); and long-term and/or younger travellers^{Reference 5}, ^{Reference 6}, ^{Reference 7}, ^{Reference 8}, ^{Reference 9}, ^{Reference 18}, ^{Reference 19}, ^{Reference 20}, ^{Reference 21}, ^{Reference 22}, ^{Reference 23}, ^{Reference 24}, ^{Reference 25}, ^{Reference 26}, ^{Reference 27}. Explanations for non-adherence are varied and include: lack of knowledge about malaria and/or its prevention; fear of or past experience with adverse effects of antimalarials; the false belief that previous malaria infections have conferred long-term immunity; the cost of medications; confusion arising from contradictory recommendations; forgetfulness; and/or lack of interest in taking antimalarial medications^{Reference 5}, ^{Reference 6}, ^{Reference 7}, ^{Reference 9}, ^{Reference 18}, ^{Reference 19}, ^{Reference 20}, ^{Reference 26}, ^{Reference 27}, ^{Reference 28}.

While the issue of non-adherence is well documented, objective evidence on how to enhance adherence is scarce. Some research has evaluated text messages as a tool to improve uptake of malaria interventions. Used as a reminder for travellers, SMS texts failed to improve adherence in one study^{Reference 29}, but was temporally associated with a reduction in malaria case reports in another study^{Reference 30}. Text messaging also has been successfully employed to enhance adherence to malaria treatment and prevention guidelines among health professionals^{Reference 31}. Other factors shown to improve adherence include receiving a pre-travel consultation^{Reference 18}, ^{Reference 25}, ^{Reference 32} and having the pre-travel intent to use preventive measures^{Reference 25}.

Education

Health care providers play a central role in educating travellers about health hazards and their prevention, including malaria^{Reference 33}. To this end, health care providers should develop and maintain their knowledge related to malaria in order to ensure up-to-date and appropriate advice is provided to their patients. Travellers should be advised of prevention measures as well as the importance of early diagnosis and treatment (see Box 1). Further, health care providers providing advice on malaria should take care to properly communicate risk, both of malaria and of the interventions used to prevent it, as this can influence the likelihood that a traveller will use a recommended practice(s)^{Reference 33}.

Travellers should be made aware that quality of health care services at their destination(s) might differ from those in Canada. Ideally, travellers will take time before departure to identify where health care facilities are located at their destination(s), and will consider obtaining travel health insurance. Health care providers can direct patients to the Government of Canada’s webpage on sickness or injury when travelling abroad^{Reference 34} for further advice on accessing medical assistance while travelling.

Prevention - personal protective measures

General

This topic is covered in detail in the CATMAT Statement on Personal Protective Measures to Prevent Arthropod Bites^{Reference 1}. The content of this statement, including its main recommendations, are summarized below.

Malaria mosquitos

Only Anopheles mosquitoes transmit malaria. These mosquitoes are often most active during the evening and, at least for the most efficient vectors, bite and rest indoors. However, some malaria vectors can or even prefer to bite outside and can feed at various times of the day, including during the late afternoon and early morning. Information about the major malaria vector(s) in a given geographic area can be useful to develop risk management strategies. For example, knowing that A. albimanus, an important vector in parts of the Americas, can bite earlier in the evening and often outside can be used to emphasize the importance of preventive modalities that are effective in that context, for example, insecticide-treated clothing and topical skin repellents.

More information on malaria and other vectors can be found in the CATMAT Statement on Personal Protective Measures to Prevent Arthropod Bites, especially “Appendix 1: Summary information for some important arthropod vectors” and its references^{Reference 1}.

Preventing malaria mosquitoes from biting

An individual can do several things to reduce the risk of malaria before travelling. These include planning activities for those periods when risk is reduced (daytime, or outside the malaria season) or going to areas where transmission is less likely, for example, urban centers. Ideally, the traveller will also prepare themselves before travel by acquiring and becoming familiar with the interventions described below.

Once the traveller is in a malaria-endemic area, the focus should be on preventing mosquito bites. The main approaches are use of physical and/or chemical barriers. These approaches are not mutually exclusive; rather, they work together and often are combined into a single intervention. For example, treated netting and clothing provides a physical and a chemical barrier.

Physical barriers

There are a variety of physical means to reduce contact between vectors and their human hosts. Recommended approaches are:

• Protect work and accommodation areas: Screening on doors, windows and eaves (the open area between the roof and wall) protects against mosquito entry as does closing holes in roofs, walls and other gaps in the building envelope^{Reference 35}, ^{Reference 36}, ^{Reference 37};
• Use of bed net: In addition to being a chemical barrier (see below), bed nets are a physical barrier against mosquitoes. They also protect against other pests like bed bugs, rodents and snakes; and,
• Wear appropriate clothing: Full-length, loose-fitting and light-coloured clothing can help to reduce exposure to mosquito bites. Ideally, sleeves should be rolled down and pants legs tucked into socks^{Reference 38}, ^{Reference 39}, ^{Reference 40}.

Chemical barriers

Chemical barriers act in several ways, including by repelling and/or by killing mosquitoes. Recommended approaches are:

• Use topical repellents on exposed areas of skin^{Reference 41}, ^{Reference 42}. Products registered in Canada and that contain 20%–30% DEET or 20% icaridin should be the first choice because they are expected to provide relatively long lasting protection. If used properly, these repellents afford very high levels of protection against the bites of malaria and other mosquitoes (e.g., >90%).
• Repellents that contain p-menthane-3,8-diol should be considered second-choice topical repellents for adults and children aged three years or older.
• Use insecticide-treated bed nets^{Reference 43}.
• Use insecticide-treated clothing to protect against the bites of malaria mosquitoes, other vectors and nuisance arthropods^{Reference 44}, ^{Reference 45}, ^{Reference 46}, ^{Reference 47}.

Other interventions

Avoid approaches that are ineffective or that have not been convincingly shown to be effective against malaria mosquitoes and other vectors. These include: electronic (ultrasonic) devices^{Reference 48}, ^{Reference 49}; wristbands, neckbands and ankle bands impregnated with topical repellent^{Reference 50}; electrocuting devices (“bug zappers”)^{Reference 48}, ^{Reference 50}; odour-baited mosquito traps; Citrosa plant (a type of geranium houseplant)^{Reference 52}, ^{Reference 53}, ^{Reference 54}; orally administered vitamin B1 ^{Reference 55}; and skin moisturizers that do not contain a recommended repellent.

Recommendations

Recommendations (Table 3.1) were not developed using GRADE methodology. Rather, they comprise non-GRADE recommendations made in other CATMAT guidelines; reflect expert judgment informed by synthesis of the evidence, and/or good practice statements^{Reference 2}. Recommendations are summarized in Table 3.1.

The recommendations identify interventions that can provide bite protection with very low potential for serious harms and low financial cost for use. These recommendations are limited by:

1. The absence of direct evidence to indicate that the recommended interventions reduce the likelihood of relevant patient important outcomes (e.g., clinical malaria) among travellers;
2. The paucity of evidence related to travellers values and preferences related to use of effective personal bite preventions measures such as repellents and bednets; and
3. The relative consistency of evidence to indicate that adherence to recommended practices among travellers is suboptimal.

Summary of recommendations

• Health care providers should remind travellers that it is important to adhere to malaria prevention practices, e.g., use of chemoprophylaxis and bite prevention measures.
• Health care providers should remind patients that it is important to seek medical attention for a febrile illness of unexplained etiology that occurs during travel or within 12 months of return from a malaria endemic area.
• Health care providers should take a travel history from all patients to help rule in (or out) the potential diagnosis of malaria (and other travel-associated diseases).
• Health care providers should develop and maintain their knowledge so as to be able to provide appropriate and traveller-specific guidance related to malaria prevention.
• Protect work and accommodations from mosquito entry by using screening on doors, windows, and eaves (the open area between the roof and wall), eliminating holes in roofs and walls, and closing other gaps in the building envelope^{Reference 35}, ^{Reference 36}, ^{Reference 37}.
• Wear appropriate clothing, e.g. full-length, loose-fitting and light-coloured clothing with sleeves rolled down and pants tucked in to socks or boots^{Reference 38}, ^{Reference 39}, ^{Reference 40}.
• Use topical repellents on exposed areas of skin^{Reference 41}, ^{Reference 42}. Products registered in Canada and that contain 20%–30% DEET or 20% icaridin should be the first choice. Repellents that contain p-menthane-3,8-diol should be considered second-choice topical repellents for adults and children aged three years or older.
• Use insecticide-treated bed nets^{Reference 43}.
• Use insecticide-treated clothing^{Reference 44}, ^{Reference 45}, ^{Reference 46}, ^{Reference 47}.

Acknowledgements

This chapter was prepared by: Schofield S, and approved by CATMAT.

Appendices

Appendix 1: search strategy

Literature search question

What are the values and preferences for travellers related to malaria prevention measures (e.g., bed nets, clothing, window screens etc.)

Embase, 2009 to March 10, 2016 [Search (Results)]

1. (Plasmodium ovale malaria/pc or malaria falciparum/pc or malaria/pc or Plasmodium knowlesi malaria/pc or Plasmodium vivax malaria/pc) and (prophylaxis/ or prevention/ or "prevention and control"/ or malaria control/) (2976)
2. (Malaria adj (prophylaxis or prevent*)).ti. (804)
3. Malaria prophylaxis.ab. /freq=2 (68)
4. Malaria prevent*.ab. /freq=2 (176)
5. Or/1-4 (3647)
6. ((Travel* or tour* or visit* or sightseer) adj4 (option or favo?r or prefer* or deci* or select* or inclin* or value* or pick* or alternative or adhere* or determin* or choice or chose or choose)).mp. (7135)
7. (Decision making/ or perception/ or high risk behavior/ or attitude to health/) and travel/ (856)
8. 6 or 7 (7931)
9. 5 and 8 (44)
10. Limit 9 to ((english or french) and yr="2009 -Current") (24)

Ovid MEDLINE(R) in-process & other non-indexed citations, Ovid MEDLINE(R) Daily and Ovid MEDLINE(R), 2009 to March 10, 2016 [Search (Results)]

1. *Malaria/pc or *malaria, cerebral/pc or *malaria, falciparum/pc or *malaria, vivax/pc (8532)
2. (Malaria adj (prophylaxis or prevent*)).ti. (593)
3. (Malaria adj (prophylaxis or prevent*)).ab. /freq=2 (225)
4. Or/1-3 (8696)
5. ((Travel* or tour* or visit* or sightseer) adj4 (option or favo?r or prefer* or deci* or select* or inclin* or value* or pick* or alternative or adhere* or determin* or choice or chose or choose)).mp. (4955)
6. (Health Knowledge, Attitudes, Practice/ or decision making/ or risk taking/ or risk factors/ or attitude to health/ or perception/) and travel/ (2726)
7. 5 or 6 (7574)
8. 4 and 7 (187)
9. Limit 8 to (yr="2009 -Current" and (english or french)) (52)

PubMed, January 1, 2009 to March 10, 2016 [Search (Results)]

((travel*[Title/Abstract] OR tour*[Title/Abstract] OR visit*[Title/Abstract]) AND (("malaria prophylaxis"[Title/Abstract] OR "malaria prevent*"[Title/Abstract]) OR ("Malaria/pc"[Mesh] OR "Malaria, Vivax/pc"[Mesh] OR "Malaria, Cerebral/pc"[Mesh] OR "Malaria, Falciparum/pc"[Mesh])) AND ((nets[Title/Abstract] OR netting[Title/Abstract] OR net[Title/Abstract] OR "ITN"[Title/Abstract] OR "LLIN"[Title/Abstract] OR repellent[Title/Abstract] OR insecticide[Title/Abstract] OR cloth*[Title/Abstract] OR air condition*[Title/Abstract] OR screen*[Title/Abstract] OR dusk[Title/Abstract]) OR (("health, attitude to"[Mesh] OR "attitude to health"[Mesh] OR "risk taking"[Mesh] OR "decision making"[Mesh]) AND ("*travel"[Mesh]))) AND (option[Title/Abstract] OR favour[Title/Abstract] OR favor[Title/Abstract] OR prefer*[Title/Abstract] OR deci*[Title/Abstract] OR select*[Title/Abstract] OR inclin*[Title/Abstract] OR value*[Title/Abstract] OR pick*[Title/Abstract] OR alternative[Title/Abstract] OR adhere*[Title/Abstract] OR determin*[Title/Abstract] OR choice OR chose OR choose)) AND (("2009/01/01"[PDat] : "2016/12/31"[PDat])) (12)

Cochrane, 2009 to March 10, 2016 [Search (Results)]

1. MeSH descriptor: [Malaria] this term only and with qualifier(s): [Prevention & control - PC] (431)
2. MeSH descriptor: [Malaria, Falciparum] this term only and with qualifier(s): [Prevention & control - PC] (330)
3. MeSH descriptor: [Malaria, Cerebral] this term only and with qualifier(s): [Prevention & control - PC] (2)
4. MeSH descriptor: [Malaria, Vivax] this term only and with qualifier(s): [Prevention & control - PC] (55)
5. #1 or #2 or #3 or #4 (766)
6. "Malaria prophylaxis" or "malaria prevent*":ti,ab,kw (Word variations have been searched) (216)
7. #5 or #6 (895)
8. MeSH descriptor: [Attitude to Health] this term only (2806)
9. MeSH descriptor: [Risk-Taking] this term only (1090)
10. MeSH descriptor: [Decision Making] this term only (1955)
11. #8 or #9 or #10 (5673)
12. MeSH descriptor: [Travel] this term only (294)
13. #11 and #12 (2)
14. Nets or netting or net or "ITN" or "LLIN" or repellent or insecticide or cloth* or air condition* or screen* or dsuk:ti,ab,kw (Word variations have been searched) (33938)
15. Option or favour or favor or prefer* or deci* or select*OR inclin* or value* or pick* or alternative or adhere* or determin* or choice or chose or choose:ti,ab,kw (Word variations have been searched) (280470)
16. #14 and #15 (14771)
17. #13 or #16 (14772)
18. #7 and #17 Publication Year from 2009 to 2016 (49)

Scopus, 2010 to March 10, 2016 [Search (Results)]

( TITLE-ABS-KEY ( malaria PRE/0 ( prophylaxis OR prevent* ) ) ) AND ( TITLE-ABS-KEY ( ( travel* OR tour* OR visit* OR sightseer ) W/4 ( option OR favo?r OR prefer* OR deci* OR select* OR inclin* OR value* OR pick* OR alternative OR adhere* OR determin* OR choice OR chose OR choose ) ) ) AND ( LIMIT-TO ( PUBYEAR , 2016 ) OR LIMIT-TO ( PUBYEAR , 2015 ) OR LIMIT-TO ( PUBYEAR , 2014 ) OR LIMIT-TO ( PUBYEAR , 2013 ) OR LIMIT-TO ( PUBYEAR , 2012 ) OR LIMIT-TO ( PUBYEAR , 2011 ) OR LIMIT-TO ( PUBYEAR , 2010 ) ) (23)

• Previous Page
• Table of Contents
• Next Page