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Fact Sheets

Malaria for longterm & ex-patriate workers

Malaria is caused by protozoan parasites of the genus Plasmodium. Four species of Plasmodium can produce the disease in its various forms - Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale & Plasmodium malaria. P. falciparum is the most widespread & dangerous of the four: untreated it can lead to fatal cerebral malaria.

Parasites are transmitted from one person to another by the female anopheline mosquito. Like all other mosquitos, the anophelines breed in water, each species having its preferred breeding grounds, feeding patterns & resting place. Sensitivity to insecticides is also highly variable.

Malaria is diagnosed by the clinical symptoms & microscopic examination of the blood. It can normally be cured by antimalarial drugs. The symptoms quickly disappear once the parasite is killed. In certain regions, however, the parasites have developed resistance to certain antimalarial drugs, particularly chloroquine. Patients in these areas require treatment with other more expensive drugs. Cases of severe disease including cerebral malaria require hospital care.

In endemic regions, where transmission is high, people are continuously infected so that they gradually develop immunity to the disease. Until they have acquired such immunity, children remain highly vulnerable. Pregnant women are also highly susceptible since the natural defence mechanisms are reduced during pregnancy.

The disease is characterized by fever & "flu-like" symptoms that may come & go, including chills, headache, muscle ache, and/or a vague feeling of illness. Vomiting or diarrhea may also occur. There may be anemia & jaundice (yellowing of the skin & whites of the eyes). Malaria symptoms can develop as early as 7 days after first being exposed & as late as several months or even longer after leaving a malarious area, when use of preventive drugs has been stopped (see Preventive Therapy). If treatment is not received for falciparum malaria, it can proceed to shock, liver & kidney failure, coma & death. While illness caused by vivax, ovale or malariae is not usually life-threatening, it can pose serious risks to the very young or very old, or to those with other illnesses. If these types of malaria are left untreated, episodes may recur at irregular times for months or possibly years, & the malariae form can recur more than 25 years after exposure.

Malaria should be suspected if you have any of the symptoms noted above, even if they are mild, & medical help should be sought immediately.

Disease Risk

The estimated risk of getting malaria varies a great deal from area to area, & it also depends on itinerary, time & type of travel. For example, longer-term residents who live in screened & air-conditioned housing are less likely to be exposed than are missionaries or volunteers.

Resistance of P. falciparum to the drug chloroquine has spread to most areas with malaria; & in some locations, such as parts of Thailand, a newer drug called mefloquine may also be ineffective. If you're planning a trip to a malarious area, you should get medical advice on which preventive drugs to use & what personal protection measures to take. Although use of preventive drugs & other precautions will greatly decrease your chances of getting malaria, such measures do not guarantee protection.

If you think you might have symptoms of malaria, you should seek medical evaluation immediately. Delay of appropriate therapy can have serious or even fatal consequences.

key Issues for Ex-pats are:
1, Minimising overall exposures to mosquitoes
2, Consider appropraiet longterm chemoprohylaxis
3, Rapid access to good diagnositcs & treatment

Primary Protection Measures

The first line of defense is to take measures to avoid contact with Anopheles mosquitoes, especially between dusk & dawn, when they feed. During these hours, you should avoid outdoor exposure and:

• Remain in air-conditioned or well-screened areas.
• Use mosquito nets.
• Wear clothes that cover most of your body.
• Apply flying-insect spray that contains pyrethroid to living & sleeping areas during evening & nighttime hours.
* For added protection against mosquitoes, bednets & clothing can be soaked in or sprayed with permethrin. When used
according to directions, permethrin can be effective on clothing for several weeks.
* Apply repellents that contain DEET to clothing & exposed skin.

The possibility of adverse reactions to DEET will be minimized if the following precautions are taken:

* Avoid applying products containing more than 35% DEET to the skin.
* Always use repellent according to label directions.
* Apply repellent sparingly only to exposed skin or clothing.
* Do not inhale or ingest repellents or get them in the eyes.
* Avoid applying repellents to portions of children's hands that are likely to have contact with their eyes or mouth.
* Never use repellents on wounds or irritated skin.
* Wash repellent-treated skin after coming indoors if there is no risk of exposure to insects.
* If a suspected reaction to insect repellent occurs, wash treated skin & seek medical attention.

Preventive Therapy

Using preventive medications (chemoprophylaxis) is an important consideration for persons living in malarious areas. The medications below are designed to prevent the disease from developing. There are other medications available to combat malaria. Your physician may recommend one of these, depending on their availability in your area and/or their effectiveness at your destination.

Mefloquine, Doxycycline, or malarone are the three main drugs used for malaria prevention, the first two are both suitable for longterm use. While malarone is also probably safe for lonterm use, no good data on that question exists, & if it used a s a prevetion drug, it cannot be used for treatment. For these reasons, The Travel Doctor-TMVC does not recommend it as first choice for longterm protection.

Doxycycline should not be taken by pregnant women or children younger than 8 years old.

Risks & Side Effects of Preventive Medications
Mefloquine

Minor side effects of mefloquine include stomach distress & dizziness, which tend to be mild & temporary. Some people may experience vivid dreams, sleep disturbance, disorientation, depression or anxiety. More serious side effects are rare when this drug is taken at the recommended dosage. Like chloroquine, mefloquine may aggravate psoriasis.

Mefloquine is not recommended for those who:

* are pregnant or are planning to become pregnant within three months of ceasing antimalarials;
* have a history of epilepsy;
* have a history of a psychiatric disorder;
* are allergic to mefloquine;
* will be scuba-diving or pilotting aircraft;
* have a cardiac conduction defect.

Doxycycline

Possible side effects include skin photosensitivity, which can result in an exaggerated sunburn reaction. Risk of this can be lowered by using sunscreen that blocks UVA rays, avoiding prolonged exposure to sunlight, & by wearing a hat. Women who take doxycycline may develop vaginal yeast infections & should talk to their doctor about this before using this drug.

Doxycycline should not be used by:

* women during their entire pregnancy;
*children under 8 years of age;
* persons who are allergic to this drug.

Doxycycline may interact with some drugs such as carbemazapine, phenytoin, phenobarbitone, antacids & iron & calcium preparations so that it may not be effective. Women taking the oral contraceptive pill are advised not to rely on the pill for contraception while taking doxycycline.

Malarone, is generally well tolerated , but gastro-intestinal side-effects are reported.

Other Potential Problems

Let your doctor know if you have heart disease or any other serious health problems, so this can be taken into consideration in the choice of an appropriate drug for malaria prevention.

There is a rare chance that other serious problems could occur after taking medication to prevent malaria, as might happen after taking any medicine or receiving any vaccine.

As with all significant medical problems, if a person has a serious or unusual reaction after taking the drugs, call a doctor or get the person to a doctor promptly.

Overdose of antimalarial drugs can be fatal. Medication should be stored in childproof containers, out of children's reach.

Timing/Dosage

Malaria chemoprophylaxis should begin two weeks before travel to malaria risk areas for mefloquine, 2 days for doxycycline, & one day before for malarone. The pre-travel dosage period allows the drug's concentration in the body's tissues to build up to an effective level, plus it gives the physician time to evaluate any side effects (see Risks & Side Effects above). In case you may have unknowingly become infected, it is important to continue the mefloquine & doxycycline for 4 weeks after leaving the risk area to allow the infection to die out harmlessly. Malarone is required for only one week after.

Pregnancy

Malaria infection can be a very serious threat to a pregnant woman & her fetus. In fact, it can cause more severe problems in pregnant women than in those who are not pregnant. Malaria increases the risk of prematurity, miscarriage, & stillbirth, making it very important that a pregnant traveler going to a malaria-risk area consult her doctor & take preventive medication. Ideally pregnant women should avoid malaria areas during pregnancy.

If exposure is unavoidable, for areas where chloroquine is still effective, it is the preferred drug for most pregnant women.
In areas that are resistant to chloroquine (most), pregnant women should consider mefloquine, especially in 2nd & 3rd trimesters. Mefloquine is not perfect, & discussion with a physician is important. Doxycycline should not be used during the entire pregnancy, & Malarone should be avoided until better information is known.

Breast-Feeding

Small amounts of antimalarial drugs may be passed on to infants who are breast-fed. The very small amount of drug in the breast milk received by the infant is not thought to be harmful. However, it is also not enough to protect infants against malaria; therefore, they need to be given appropriate drugs in dosages according to their weight. Each malaria attack must be treated promptly.

Temporary Self-Treatment

In addition to careful personal protection measures (previously mentioned), travelers who are using chloroquine in a chloroquine-resistant area, or who have decided not to take antimalarial drugs should carry a treatment dose of a drug such as mefloquine, Malarone® or Riamet®, to use in case malaria infection occurs or is suspected. No one who has a sulfa allergy should take Fansidar. These drugs should be taken in the appropriate dosage to treat any fever during travel, but only if professional medical help is not available within 24 hours. The children's dose is based on weight.

Such self-treatment of possible malaria infection is only a temporary measure, & medical care should be sought immediately.

Liver treatment after malaria exposure

Where plasmodium vivax is the predominant species, liver clearance is required after vivax infections, or on leaving the malaria area to prevent the latent infection in the liver from coming out afterwards & causing relapsing malaria.

For this, the drug primaquine is used, the dose based on body weight, & it can be given safely to those who have a normal G6PD enzyme level (blood test)