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

Appendix III Frequently Asked Questions (FAQs) About Malaria

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1. Is malaria a serious infection for healthy people?

Malaria is a major killer worldwide and is the principal life-threatening infectious disease for Canadians travelling to areas of malaria risk globally. Canadian travellers who were born, grew up or previously lived in malarial areas are NOT protected from malaria and remain at risk regardless of past exposures and episodes of illness. Between 400 and 1,000 cases of malaria are reported among Canadian travellers annually, with one to two malaria deaths annually.

2. Do all travellers to the tropics need malaria prophylaxis?

Many destinations in the tropics are either free of malaria, or the risk is so low that malaria prophylaxis is not needed. Furthermore, some travellers to countries with known malaria risk may not need to take malaria prophylaxis because malaria transmission may be confined to particular areas of a country (usually rural areas) or may be seasonal. For example, most individuals travelling only to major urban centres or resort areas in Central and South America or Southeast Asia do not require malaria prophylaxis. However, ALL travellers (adults and children) to any area with any risk of malaria should use personal protective measures, such as treated mosquito nets and insect repellents, to avoid mosquito bites. The risk of malaria can change rapidly in malaria-free zones within malaria risk countries. Therefore up-to-date information is essential in determining risk.

3. What if I don't see any mosquitoes when I reach my destination? Can I stop taking preventative medications or using mosquito precautions?

No, even if you do not notice mosquitoes you should continue taking malaria prevention medications. The mosquitoes that pass malaria infection to humans typically rest during the day and become active at night and during twilight hours when they are difficult to see. In addition, these species of mosquitoes are inaudible to humans.

4. Should pregnant women, babies and children receive malaria prophylaxis?

Pregnant women, babies and small children are at particular risk of severe malaria or complications. If they must go to high-risk areas, the best available malaria prevention medications should be used, along with rigorous attention to personal protective measures. Several effective prevention regimens are known to be safe in these groups. It is important to remember that drugs taken by nursing mothers will not provide protection for the nursing child.

5. Do most people who take malaria prophylaxis have serious side effects?

For travellers to high-risk areas, the risk of acquiring malaria and dying is significantly greater than the risk of experiencing a serious side effect from malaria prophylaxis. The great majority of people taking malaria prophylaxis (95% to 99%) have either no side effects or only mild and temporary ones. In most studies, only 1% to 6% of people change to an alternative drug because of side effects. Reactions to malaria prevention medications are almost always reversible. Death from malaria, however, is not.

The final choice of which antimalarial drug to use should be based on an individual risk assessment from a knowledgeable travel medicine provider, which should include issues such as the drug's effectiveness, the traveller's willingness to accept potential side effects, the convenience of dosing (weekly versus daily), the cost and the traveller's medical history, including contraindications to antimalarial drugs.

6. Are there safer and/or more effective antimalarial drugs available?

For high-risk regions of the world with chloroquineresistant malaria, three drugs that are equally effective are currently licensed in Canada: atovaquone/ proguanil (Malarone^® ), doxycycline and mefloquine (Lariam®). Each has advantages and disadvantages. Travellers should be aware that cheaper, locally available drugs, such as chloroquine, proguanil (Paludrine^® ), amodiaquine (Camoquine^® ), pyrimethamine (Daraprim^® ), pyrimethamine plus sulfadoxine (Fansidar^® ) and pyrimethamine plus dapsone (Maloprim^® ), may be ineffective, counterfeit, more toxic or inappropriate for high-risk individuals. Travellers may obtain advice from many different sources, including websites, other travellers and residents or health care workers in endemic countries. However, before departure, travellers should consult a health care provider with knowledge of travel medicine for an informed recommendation regarding malaria prophylaxis for their planned itinerary.

7. If I take preventive medications for malaria, is there still a chance I can get sick with malaria?

Proper use of an effective preventive medication for malaria provides a high degree of protection and can reduce the risk of malaria illness by more than 90%, but no preventive medication is 100% effective. Therefore, even if you have taken preventive medication, malaria is still possible and should be considered if you develop an illness with fever during or after travel to malarial areas.

8. If I take prophylaxis, won't it be harder to diagnose malaria if I get it?

Use of malaria prophylaxis may reduce the severity of symptoms and the number of parasites in the blood and therefore could – rarely – result in a minor delay in making a definitive diagnosis by some methods. However, properly used prophylactic drugs will prevent the vast majority of malaria episodes, reduce the risk of severe disease and will not prevent a definitive diagnosis if proper testing is done. The small risk of a slight delay in diagnosis must be contrasted with the significant benefit of preventing disease and reducing the risk of severe disease.

9. If I take prophylaxis, will the malaria I get be more resistant to treatment?

The prevention of malaria in travellers using prophylactic drugs does not promote the development of resistant malaria parasites. Appropriately used, prophylaxis can actually reduce resistance by lowering the burden of malaria disease.

10. Is there a limited period in which one can take prophylaxis safely?

There is no absolute time limit on how long one can take any antimalarial prophylactic drug. The few individuals who experience significant side effects from antimalarial drugs usually do so within the first few weeks of use. If side effects are significant, then an alternative drug for malaria prevention should be used. Many mild side effects tend to diminish over time, even with continued use of the drug. Travellers who are concerned about their ability to tolerate medications may wish to consult a travel medicine practitioner well before the travel date and consider a trial of the malaria preventive medication before departure. Long-term travellers should not discontinue a well-tolerated and effective preventive drug simply because they have been taking it for any arbitrary period of time.

11. Is it true that some malaria cannot be treated?

If identified early and treated appropriately, almost all malaria can be completely cured. However, even short delays in the diagnosis of malaria can make treatment more difficult and less successful, and can increase the risk of serious complications.

12. Once you are infected with malaria, are you are infected for life?

Appropriate treatment and follow-up can ensure complete cure of malaria.

13. Is it true that individuals born and raised in a malaria country are immune for life?

Individuals raised in areas where malaria is common often suffer repeated attacks of malaria in childhood (and many die from severe malaria). Those who survive slowly develop a partial degree of immunity to malaria that results in a decreased frequency and severity of attacks. However, this immunity never fully protects them from malaria infection (or severe disease) and diminishes quickly once an individual leaves a malarial area. Travellers returning to a malaria risk birth country after a period of absence are at high risk of infection and severe disease from malaria and should take both personal protective precautions against mosquito bites as well as malarial prevention medications.

14. How would I know if I develop malaria?

Any individual who has travelled to malarial areas and subsequently develops fever should urgently seek medical advice (even if the fever appears many months after returning to Canada) and request testing to rule out malaria. Early symptoms include headache, muscle or joint aches, backache, fatigue, nausea and low appetite. The classic symptoms of malaria (a cyclical pattern of severe shaking chills, high fever and sweats) are often absent in mild or early cases. Symptoms may mimic other common diseases such as minor viral infections, influenza, gastroenteritis and pneumonia, and the diagnosis of malaria can easily be overlooked if specific testing is not done.

15. Why do I need to continue taking medications even after I have left the malaria-risk area?

Most malaria preventive medications do not actually prevent the initial stages of infection when the parasites are found in the liver but, rather, work only once the parasite has completed its development in the liver and entered the blood stream. The initial phase of infection in the liver can last from 8 days to several months, although the majority of malaria cases occur within the first month after leaving the malarial area. Most prevention medications (chloroquine, mefloquine, doxycycline) must be continued for 4 weeks after exposure ceases to prevent disease caused by parasites, which are in the liver stage when the traveller leaves the malaria-endemic area. Several malaria prevention medications (atovaquone/ proguanil, primaquine) are effective against the liver stages of infection, and these medications may be discontinued several days to 1 week after leaving the malaria-risk area. When malaria prevention medication is prescribed, you will be advised as to how long it should be taken after leaving the malaria-risk area. Further information on issues related to travel medicine is available through the Travel Health Program of the Public Health Agency of Canada.