Health Library - Malaria

Health Library - Malaria

What is malaria?

Malaria is a serious infection. It is common in tropical countries such as parts of Africa, Asia and South America. It is caused by a parasite (germ) called plasmodium that lives in mosquitoes. The parasite is passed to humans from a mosquito bite.

Most infections occur in travellers returning to the UK (rather than visitors coming to the UK). The risk of getting malaria is greatest if you do not take your anti-malarial medication or do not take it properly. People who take last-minute holidays and also those visiting friends or relatives abroad have been shown to be the least likely to take their anti-malarial medication.

It is estimated that worldwide there are 300-500 million cases of clinical malaria each year and about 40% of the world's population is at risk of acquiring malaria. Each year around 1,700 people in the UK develop malaria which has been caught whilst abroad. About nine people die from malaria in the UK each year. Malaria can kill people very quickly if it is not diagnosed promptly.

Note: if you feel unwell and have recently visited an area in which there is malaria you should seek prompt medical advice, even if you have taken your anti-malarial medication correctly.

Preventing malaria

The risk of malaria for people travelling to affected areas is significant, so it is important to take precautions to prevent it.

Approximately 1,500 travellers return to the UK with malaria every year. Most of the malaria imported to the UK is caused by plasmodium falciparum and is acquired in Africa.

Many cases of malaria can be prevented by the ABCD approach:

• Aawareness of risk: know your risk of malaria.
• Bbite prevention: avoid bites as much as possible.
• Chemoprophylaxis: take the right antimalarial tablets.
• Ddiagnosis: get immediate medical help for symptoms.

Awareness of the risks

The risk of being bitten by a mosquito and the type of malaria transmitted varies, depending on the country you're visiting and the time of year.

Measures to avoid bites should always be taken. If malaria is prevalent in an area you're travelling to, you would be wise to take preventive medicine.

You can check whether you need to take preventative malaria treatment for the country that you are visiting by looking at the Fit for Travel or National Travel Health Network websites. Click on the countries you intend on visiting and check whether it is recommended that you take malaria tablets.

For optimal prevention of malaria, protection from mosquito bites is essential - even if you're taking preventive medicines.

Bite avoidance

Mosquitoes bite particularly at twilight and at night, so you should take most precautions during this time. Sleep in rooms that are properly screened with gauze over the windows and doors. There should be no holes in the gauze and no unscreened entry points to the room. Air-conditioned rooms are good, too.

Spray the room with an insecticide before entering to kill any mosquitoes that have got inside during the day.

Otherwise, you should use a mosquito net around your bed, impregnated with an insecticide such as pyrethrum (a harmless substance manufactured on the basis of extract of chrysanthemum) or permethrin (the artificial version of the same).

Long trousers, long-sleeved clothing and socks thick enough to stop the mosquitoes biting will also protect you, and should be worn outside after sunset. But it may be hard to follow such advice in a hot climate. Light colours are less attractive to mosquitoes.

While you will not be able to avoid bites completely, the less you and your family are bitten, the less likely you are to catch malaria. Below are a number of things you can do to help prevent being bitten by mosquitoes:

• Ideally, stay somewhere with effective air conditioning and screening on doors and windows. If this is not possible, try to stay somewhere with doors and windows that close.
• If you are not sleeping in an air-conditioned room or if the air-conditioning is not effective, you must sleep under an intact mosquito net that has been treated with insecticide.
• Use insect repellent on your skin and in sleeping environments. Remember to reapply frequently.
• The most effective repellents contain diethyltoluamide (DEET) and are available in sprays, roll-ons, sticks and creams.
• Wear light, loose-fitting trousers, rather than shorts, and shirts that have long sleeves. This is particularly important during early evening and at night, as this is the mosquito's preferred feeding time.

Garlic, vitamin B and ultrasound devices do not prevent bites.

Use mosquito repellent cream

Mosquito repellent containing diethyl toluamide (DEET) is recommended as the most effective form of bite-preventive treatment. It has an excellent safety profile in adults, children and pregnant women and has been used in over 8 billion doses in the last 50 years.

There will always be people who dislike DEET, and for them there are other products - such as non-DEET Jungle Formual, Bayrepel or Mosiguard (made from eucalyptus oil). It's important that the manufacturer's recommendations are not exceeded, particularly when using it on small children.

Insect repellents containing over 30 to 50 per cent DEET will effectively repel mosquitoes when applied to exposed skin.

Insecticide-treated mosquito nets

When sleeping outdoors or in an unscreened room, have an insecticide-treated mosquito net around your bed. This significantly reduces the risk of bites. The net should be small-meshed, with no holes, and tucked in under the bottom sheet. During the day, it should be rolled up, so mosquitoes and other insects can't get inside while it's not in use.

Take your own net with you. You can't always expect to find an impregnated net at your destination. Impregnation lasts from six months to one year, depending on how much the net is used and whether you pack it away in a plastic bag when you return from the tropics. Just remember not to wash the net in between re-impregnation with the insecticide!

Preventative medicines: taking appropriate antimalarial tablets (chemoprophylaxis)

Taking medicine to prevent catching malaria is essential for all travellers who are visiting areas with malaria. However, antimalarials are not 100% effective, so avoiding bites is also important.

Taking antimalarial medicine:

• Make sure you get the right antimalarial tablets before you go.
• You will have to pay for your antimalarials, so include the cost in your trip budget.
• Follow the instructions included with your tablets carefully.
• It is important that you continue to take your tablets after you return from your trip. This is to cover the incubation period of the disease.
• Most tablets need to be taken for four weeks after you return, although atovaquone plus proguanil (Malarone) needs to be taken for only one week.

Talk to your doctor to make sure that you are prescribed a drug you can tolerate. You may be more at risk from side effects if you have:

• AIDS/HIV
• epilepsy or any type of seizure
• depression
• heart problems
• liver or kidney disease
• porphyria (an inherited condition that causes sensitivity to sunlight)
• psoriasis
• psychiatric problems

You may also be more at risk from side effects if:

• your spleen has been removed or does not work properly
• you take medicine (such as warfarin) to prevent blood clots
• you are a woman using combined hormonal contraception, such as the pill or patches

If you have taken antimalarial medicine in the past, do not assume that it is suitable for future trips. The medicine you need to take depends on the strain of malaria carried by the mosquitoes and drug resistance in the region that you are travelling to.

In Britain, chloroquine and proguanil can be brought from local pharmacies. For all other antimalarial tablets, you need a doctor's prescription.

Diagnosis: get prompt medical advice

If you become ill when you get back from travelling, even if you took the right malaria prevention tablets, you must see your GP or a hospital doctor straight away.

Tell the doctor that you have been exposed to malaria. It is important that you tell them which countries you have travelled to in the last 12 months, including brief stopovers.

Malaria can develop very quickly, so it is important to get medical advice, diagnosis and treatment as soon as possible if you think you may have malaria.

Antimalarial medicine for treatment

With prompt diagnosis and treatment, most people make a full recovery from malaria. If you have been diagnosed with malaria, your treatment must start as soon as possible.

Malaria can be treated using the same antimalarial medicines taken to prevent malaria. However, if you have taken a preventive anti-malarial medicine, your doctor should not give you the same one to treat your malaria. Therefore, it is important you tell your doctor what tablets you took to prevent malaria.

The antimalarial medicine that you are prescribed and the length of your treatment depend on:

• the type of malaria you have
• how bad your symptoms are
• where you caught malaria
• if you took antimalarial tablets
• whether you are pregnant
• your age

Your doctor will check the most recent advice and recommend the right treatment for you. They may recommend a combination of different medicines to overcome strains of malaria that have become drug-resistant.

Often, antimalarial treatment is given as tablets or capsules. If you are very ill, you will be admitted to hospital and treatment is usually given through a drip into a vein in your arm.

Treatment for malaria can leave you feeling very weak and tired for several weeks.

Emergency standby treatment

This is a course of medicine that can be taken for malaria symptoms if you cannot reach a doctor while you are travelling overseas.

Research has shown that emergency standby treatment is often used incorrectly. It should only be considered for travellers who are going to be in very remote areas away from medical help.

It is not a substitute for taking the right malaria prevention tablets. Your doctor should get advice from a travel health specialist before prescribing emergency standby treatment.