Malaria Prevention

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QUESTION

What are the ways in which you can prevent yourself from being infected with malaria?

ANSWER

Malaria prevention consists of a combination of mosquito avoidance measures (since malaria is transmitted by infected mosquitoes) and chemoprophylaxis (medication to prevent the establishment of malaria in your body, if you do get bitten). Although very efficacious, none of the recommended interventions are 100% effective.

Mosquito Avoidance Measures

  • Because of the nocturnal feeding habits of Anopheles mosquitoes, malaria transmission occurs primarily between dusk and dawn.
  • Contact with mosquitoes can be reduced by remaining in well-screened areas, using mosquito bed nets (preferably insecticide-treated nets), using a pyrethroid-containing flying-insect spray in living and sleeping areas during evening and nighttime hours, and wearing clothes that cover most of the body.
  • All travelers should use an effective mosquito repellent.
  • The most effective repellent against a wide range of vectors is DEET (N,N-diethylmetatoluamide), an ingredient in many commercially available insect repellents. The actual concentration of DEET varies widely among repellents. DEET formulations as high as 50% are recommended for both adults and children older than 2 months of age (see the Protection Against Mosquitoes, Ticks, and Other Insects and Arthropods section later in this chapter). DEET should be applied to the exposed parts of the skin when mosquitoes are likely to be present.
  • In addition to using a topical insect repellent, a permethrin-containing product may be applied to bed nets and clothing for additional protection against mosquitoes.

Chemoprophylaxis

      • All currently recommended primary chemoprophylaxis regimens involve taking a medicine before travel, during travel, and for a period of time after leaving the malaria endemic area. Beginning the drug before travel allows the antimalarial agent to be in the blood before the traveler is exposed to malaria parasites.
      • Presumptive antirelapse therapy (also known as terminal prophylaxis) uses a medication towards the end of the exposure period (or immediately thereafter) to prevent relapses or delayed-onset clinical presentations of malaria caused by hypnozoites (dormant liver stages) of P. vivax or P. ovale. Because most malarious areas of the world (except the Caribbean) have at least one species of relapsing malaria, travelers to these areas have some risk for acquiring either P. vivax or P. ovale, although the actual risk for an individual traveler is difficult to define. Presumptive anti-relapse therapy is generally indicated only for persons who have had prolonged exposure in malaria-endemic areas (e.g., missionaries, volunteers).
      • In choosing an appropriate chemoprophylactic regimen before travel, the traveler and the health-care provider should consider several factors. The travel itinerary should be reviewed in detail and compared with the information on where malaria transmission occurs within a given country to determine whether the traveler will actually be traveling in a part of the country where malaria occurs and if significant antimalarial drug resistance has been reported in that location.
      • The resistance of P. falciparum to chloroquine has been confirmed in all areas with P. falciparum malaria except the Caribbean, Central America west of the Panama Canal, and some countries in the Middle East. In addition, resistance to sulfadoxine–pyrimethamine (e.g., Fansidar) is widespread in the Amazon River Basin area of South America, much of Southeast Asia, other parts of Asia, and in large parts of Africa. Resistance to mefloquine has been confirmed on the borders of Thailand with Burma (Myanmar) and Cambodia, in the western provinces of Cambodia, in the eastern states of Burma (Myanmar), on the border between Burma and China, along the borders of Laos and Burma, and the adjacent parts of the Thailand–Cambodia border, as well as in southern Vietnam.
      • Additional factors to consider are the patient’s other medical conditions, medications being taken (to assess potential drug–drug interactions), the cost of the medicines, and the potential side effects.

The medications recommended for chemoprophylaxis of malaria may also be available at overseas destinations. However, combinations of these medications and additional drugs that are not recommended may be commonly prescribed and used in other countries. Travelers should be strongly discouraged from obtaining chemoprophylactic medications while abroad. The quality of these products is not known, and they may not be protective and may be dangerous. These medications may have been produced by substandard manufacturing practices, may be counterfeit, or may contain contaminants. Additional information on this topic can be found in an FDA document

Purchasing Medications Outside the United States.

Malaria in Borneo, Indonesia

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QUESTION

We fly to Borneo tomorrow and have been very stupid not thinking about Malaria medication. Can someone quickly tell if I should take medication when there and also what type would be best to take?

Thank you for your help.

ANSWER

Yes! Malaria prophylaxis is recommended for trips to Indonesian Borneo, particularly rural areas. Recommended forms of prophylaxis are Malarone (atovaquone-proguanil), doxycycline and Lariam (mefloquine). The first is the most expensive, but has the fewest side effects, the second is the cheapest but can induce sun sensitivity and needs to be taken for 4 weeks after returning home and the third only requires one pill a week (the others are taken daily) but side effects can be severe and disturbing, including vivid dreams, impaired consciousness and hallucinations.

I am less familiar with south-east Asia, but I know in Africa doxycycline is readily available, for very little money, at local pharmacies. Therefore if you don’t have time to get the necessary anti-malarials before you leave, don’t panic! You may well be able to buy them in-country, particularly if you stop in Jakarta or another major city on your way. Check expiry dates and make sure the drugs are in the original packaging before you purchase though, as counterfeit drugs are distressingly prevalent. Also, do not buy chloroquine (or indeed any anti-malarial not listed above)—malaria in Borneo has been reported to be resistant to chloroquine and so this is not an appropriate anti-malarial for this area.

Please consider sharing your experiences with whichever prophylactic you choose when you return from your trip. We at MALARIA.com are trying to compile data on people’s experiences with malaria prophylactics and treatment medication, and we would be very grateful if you would take our malaria survey. Thank you!

Please also use other preventative measures against malaria while you are in Borneo—sleeping underneath an insecticide-treated bednet and wearing long-sleeved clothing in the evenings and at night, plus applying insect-repellent to exposed skin, can all help to reduce the incidence of mosquito bites and thus the risk of contracting malaria. Plus, avoiding insect bites will probably improve your enjoyment of the trip as a whole!

How to Protect from Malaria

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QUESTION

How can I protect my body from malaria?

ANSWER

There are a number of ways to prevent malaria. These can be placed into two categories: medication and vector protection.

For medication, there are drugs you can take to prevent the malaria parasite from developing after someone is bitten by an infected mosquito. These drugs are known as “chemoprophylaxis”.

There are several different kinds, such as doxycycline, mefloquine (marketed as Lariam), atovaquone-proguanil (marketed as Malarone) and chloroquine—the type you use depends on the type of malaria present in the area. For example, in much of Africa and India, malaria is resistant to chloroquine, so this cannot be used as a prophylactic. In parts of Thailand, resistance to mefloquine has emerged. However, if the appropriate type of prophylaxis is used, it is very effective against malaria.

The problem is that these drugs have not been tested for long-term use, can be expensive and may have side-effects. Therefore they are of limited use for people who live in areas where malaria is endemic, and are more appropriate for travelers who are in malarial areas for short amounts of time. However, anti-malarial medication may be used in a very specific way for people at particularly high-risk for malaria, such as pregnant women and young children. In these cases, the high-risk individuals receive a dose or series of doses of malaria medication in order to prevent malaria. This form of prevention is known as intermittent preventive therapy (IPT).

Vector prevention involves protecting oneself against getting bitten by mosquitoes. This can involve wearing long-sleeved clothing in the evenings and at night, when malaria mosquitoes are most active, or wearing insect repellent on exposed skin. Indoor residual spraying, whereby repellent and insecticides are sprayed inside the house, can also be used to bring down the number of mosquitoes.

Another very effective technique for preventing malaria is to sleep under a long-lasting insecticide-treated bednet. The mesh acts as a barrier against the mosquitoes, and the insecticide impregnated in the mesh further repels the mosquitoes and prevents them from biting through the mesh.