Family doctor

Overview:

• Malaria is transmitted by mosquito bites
• Malaria is a serious illness and can lead to coma and death
• Symptoms usually begin within seven to 30 days after a bite
• Malaria symptoms include sweats, fever, chills, and may feel like the flu
• Children and pregnant women are especially vulnerable
• Reducing your risk includes avoiding bites and taking prophylactic drugs
• No drug is 100% protective
• There is no perfect preventative drug-the choice needs to be tailored to the individual
• All drugs have potential side effects - the vast majority of people have none.
• Reducing your risk requires careful expert advice

What is it?

Malaria is a serious disease transmitted to humans by the bite of the Anopheles mosquito. There are 4 types of malaria, but only Falciparum Malaria poses any life-threatening risk to humans. Two of the other types of malaria can persist in a person's blood for many years after infection - unless specific treatment is used.

There is no successful vaccine available, but treatment given promptly enough is usually effective, although there are now some strains Falciparum malaria that have developed resistance to many of the usual medication used. Malaria causes over a million deaths a year, the majority being in Sub-Saharan Africa. In addition to Africa, other frequently visited tourism areas of the world with malaria include Southern and South-East Asia, Mexico, Haiti, the Dominican Republic, Central and Southern America, Papau New Guinea, Vanuatu, the Solomon Islands, the sub-continent of India / Pakistan / Bangladesh, some areas of the Middle East, Fiji, Sri Lanka, and Philippines.

The disease's geographic distribution is variable upon time of year, recent mosquito eradication efforts, altitude, and population movements. Rural and urban areas often are very different in their risk-especially in SE Asia and South America, where most cities are risk free. In Africa and the sub-continent this is not usually the case. It is hence important that those entertaining a visit to a possible malarial area receive up to date malaria-risk recommendations from a reliable source regarding not just the general country malaria risk, but more specifically the area within a country.

Local inhabitants in malarial areas develop some resistance to the malaria parasite, and tourists from non-malarial countries are hence much more vulnerable to the severe consequences of the infection than locals - so do not be fooled by any complacency of the locals. Severe illness, or death from malaria, are possible consequences of any infection, but are more likely in pregnant women, children and those who have had a spleen removed.

What are the symptoms?

Malaria is marked by sweating, fever, chills, aches and pains, and headache, and it may be mistaken for the flu. Even diarrhoea and vomiting without the above symptoms can represent an attack. The earliest onset of these symptoms is 7 days after a mosquito bite. The onset can be many months later - often well after the person has left the malarial area and returned home. Hence you must tell your doctor about your recent travel to a malaria area if you contract any illness within even months of your return home.

The infection can still occur in those who have taken their recommended prophylactics against malaria. A recall of not having been bitten by a mosquito is not reliable in excluding infection. If malaria is suspected, medical attention must be sought as soon as possible.

Usually a blood test is required to confirm malaria. Very accurate (relatively cheap and user-friendly) finger-prick tests to diagnose Falciparum malaria are available for self-testing, and are highly recommended for those travelling to remote areas. Those using these tests can take with them a treatment course of pills (Standby Treatment-see below) to use in the event of a positive test. The test does not ordinarily replace the need for prophylaxis or other preventive measures against malaria (see below), but is an adjunct to these.

What is the treatment?

Treatment with medication is usually effective. Due to the developing resistance of malaria in some areas of the world, more than one type of medication is usually prescribed concurrently, and blood tests are required after treatment to ensure the infection is cured. Medications used are often higher, and longer doses, of those taken for prophylaxis, mentioned below.

If there might be a delay in reaching a facility that is able to diagnose malaria, many travellers carry with them stand-by-treatment (SBT). This is medication to take if you think you have the symptoms of malaria - or if your self-test skin prick test (see above) is positive for malaria. The best SBT available today is Malarone - a 3 day expensive treatment that is still not widely available globally. Fansidar tablets might be recommended in some parts of the world for SBT, as might mefloquine (Lariam). The choice of what to carry with you for SBT is dependent on what you are taking for prophylaxis and what part of the world you are visiting. Expert advice is essential in making this choice. If the SBT is indeed taken on your trip, it is essential to still seek medical attention as soon as possible. SBT is hence only a stopgap until you can get further help!

How can it be prevented?

There is no vaccine but taking anti-malaria medication and avoiding mosquito bites whilst travelling reduce your risk. There is no 100% effective medication to prevent malaria - so one can still contract malaria, despite taking prophylaxis, albeit at a much reduced risk.

The most common drug prophylactics are mefloquine (Lariam), doxycycline, proguanil (Palludrine) and chloroquine. Some of these are taken everyday - others just once a week. The choice depends on the area of travel, the time of year, age, allergies and other medical problems of the traveller, and whether one is pregnant. Minor abdominal side-effects are not uncommon with these drugs, but usually settle with subsequent doses, and are reduced by taking the medicine at the same time every week/day with food. It is important that the chosen drug be started at the correct time before travel - 2 days before with doxycycline - 2 weeks before for mefloquine. The drug must be taken for the duration of malaria exposure and for 4 weeks after returning - this is most important.

Mefloquine must not be taken by those with a history of fits or mental illness. Those with psoriasis should avoid chloroquine. Children under 8 years of age and pregnant women can not use doxycycline. The choice of drug must be made in collaboration with an expert professional.

Taking preventative drugs does not allow complacency about mosquito bites - as no drug is 100% preventative. The mosquito tends to bite from dusk to dawn - i.e. overnight. Venturing into malarial rural areas in the low-risk daytime and choosing accommodation with screens or air-conditioning is important. Sleeping under mosquito nets, especially if treated with Permethrin, has shown to greatly reduce the risk of contracting malaria.. Wear long-sleeve pants and shirts outdoors at night, and apply repellents containing DEET (N,N-diethyl-m-toluamide- of no greater than about 35% concentration - higher is most irritant to the skin, and even 35% can cause side-effects in children) to exposed skin. Your travel clothing can be treated with Permethrin - a safe insecticide for adult and child. This will endure up to five clothes washes or several weeks of wear, before needing re-application. Use insecticide in your sleeping quarters at night, either as a spray, coil, candle or electronic plug-in mat variety. Avoid using scented perfumes or aftershaves, as these attract mosquitoes.

Future trends

Malaria continues to present a major risk to almost half the world's population. Numerous successful drugs against malaria or the mosquito have lost their effectiveness due to the development of resistance by the parasite or mosquito. Poor political will and entrenched poverty of many malaria-infested nations has made eradication of malaria further impossible. The development of a vaccine against malaria is the most likely means of controlling this disease. Numerous approaches to a vaccine are being researched. The earliest of these can still not provide more than 20-30% protection. The risk of spread to new areas of the globe exists. The risk to tourists to many parts of the world must not be under-estimated.