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Travel health – Malaria

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Travel health – Malaria



Introduction 

Malaria is a serious tropical disease spread by mosquitoes. If malaria is not diagnosed and treated promptly, it can be fatal.

A single mosquito bite is all it takes for someone to become infected.

Symptoms of malaria

It is important to be aware of the symptoms of malaria if you are travelling to areas where there is a high malaria risk (see below). Symptoms include:


a high temperature (fever)

sweats and chills

headaches

vomiting

muscle pains

diarrhoea


Symptoms usually appear between seven and 18 days after becoming infected, but in some cases the symptoms may not appear for up to a year, or occasionally even longer.

When to seek medical attention

Seek medical help immediately if you develop symptoms of malaria during or after a visit to an area where the disease is found, even if it is several weeks, months or a year after you return from travelling.

If there is a possibility you have malaria, a blood test will be carried out to confirm whether or not you are infected.

You should receive the results of your blood test on the same day and, if you have malaria, treatment will be started straight away.

What causes malaria?

Malaria is caused by a type of parasite known as plasmodium. There are many different types of plasmodia parasites, but only five cause malaria in humans.

The plasmodium parasite is mainly spread by female Anopheles mosquitoes, which predominantly bite at night. When an infected mosquito bites a human, it passes the parasites into the bloodstream.

Malaria can also be spread through blood transfusions and the sharing of needles, but this is very rare.

Malaria risk areas

Malaria is found in more than 100 countries, mainly in tropical regions of the world, including:


large areas of Africa and Asia

Central and South America

Haiti and the Dominican Republic

parts of the Middle East

some Pacific islands


The World Malaria Report, published by the World Health Organization (WHO) in 2013, states that in 2012 there were 207 million cases of malaria worldwide and 627,000 deaths.

Malaria is not found in the UK, although about 1,400 travellers were diagnosed with malaria after returning to the UK from the areas above in 2012. Two people died.

The Fit for Travel website has more information about the risk of malaria in specific countries.

Preventing malaria

Many cases of malaria can be avoided. An easy way to remember is the ABCD approach to prevention:


Awareness of risk – find out whether you're at risk of getting malaria before travelling.

Bite prevention – avoid mosquito bites by using insect repellent, covering your arms and legs and using an insecticide-treated mosquito net.

Check whether you need to take malaria prevention tablets – if you do,make sure you take the right antimalarial tablets at the right dose, and finish the course.

Diagnosis – seek immediate medical advice if you develop malaria symptoms, including up to a year after you return from travelling.


Speak to your GP if you are planning to visit an area where there is a malaria risk. It may be recommended that you take antimalarial tablets to prevent infection.

Treating malaria

If malaria is diagnosed and treated promptly, virtually everyone will make a full recovery. Treatment should be started as soon as the diagnosis has been confirmed.

Antimalarial medication is used both to treat and prevent malaria. Which type of medication is used and the length of treatment will depend on:


the type of malaria

the severity of your symptoms

where you caught malaria

whether you took an anti-malarial to prevent malaria 

whether you are pregnant


In some cases, you may be prescribed emergency standby treatment for malaria before you travel if there is a risk of you becoming infected with malaria while travelling in a remote area with little or no access to medical care

Complications of malaria

Malaria is a serious illness that can get worse very quickly and can be fatal if not treated promptly.

It can also cause serious complications including:


severe anaemia – where red blood cells are unable to carry enough oxygen around the body, leading to drowsiness and weakness

cerebral malaria – in rare cases, the small blood vessels leading to the brain can become blocked, causing seizures, brain damage and coma


The effects of malaria are usually more severe in pregnant women, babies, young children and the elderly. Pregnant women in particular are usually advised not to travel to malaria risk areas.

Symptoms of malaria 

Symptoms of malaria can develop as quickly as seven days after you are bitten by an infected mosquito.

Typically, the time between being infected and when symptoms start (incubation period) is seven to 18 days, depending on the specific parasite you are infected with. However, in some cases it can take up to a year for symptoms to develop.

The initial symptoms of malaria are flu-like and include a high temperature (fever), headache, sweats, chills and vomiting. These symptoms are often mild and can sometimes be difficult to identify as malaria.

With some types of malaria, the fever occurs in four to eight hour cycles. During these cycles, you feel cold at first with shivering that lasts for up to an hour. You then develop a fever that lasts for two to six hours, accompanied by severe sweating.

Other symptoms of malaria can include: 


muscle pains

diarrhoea

generally feeling unwell


If you become infected with the most serious type of malaria, caused by the Plasmodium falciparum parasite, there is a risk you could quickly develop severe and life-threatening complications such as breathing problems and organ failure if you are not treated promptly.

Seeking medical advice

Seek medical advice immediately if you develop symptoms of malaria during or after a visit to an area where the disease is found, even if it is several weeks, months or a year after you return from travelling.

Causes of malaria 

Malaria is caused by the plasmodium parasite. The parasite can be spread to humans through the bites of infected mosquitoes.

There are many different types of plasmodium parasite, but only five types cause malaria in humans. These are:


Plasmodium falciparum – mainly found in Africa, it is the most common type of malaria parasite and is responsible for most malaria deaths worldwide.

Plasmodium vivax – mainly found in Asia and South America. This parasite causes milder symptoms than Plasmodium falciparum, but it can stay in the liver for up to three years, which can result in relapses.

Plasmodium ovale – fairly uncommon and usually found in West Africa. It can remain in your liver for several years without producing symptoms.

Plasmodium malariae – this is quite rare and usually only found in Africa.

Plasmodium knowlesi – this is very rare and found in parts of South East Asia.


How malaria is spread

The plasmodium parasite is spread by female Anopheles mosquitoes, which are known as 'night-biting' mosquitoes because they most commonly bite between dusk and dawn.

If a mosquito bites a person already infected with malaria, it can also become infected and spread the parasite on to other people. However, malaria cannot be spread directly from person to person.

Once you are bitten, the parasite enters the bloodstream and travels to the liver. The infection develops in the liver before re-entering the bloodstream and invading the red blood cells.

The parasites grow and multiply in the red blood cells. At regular intervals, the infected blood cells burst, releasing more parasites into the blood. Infected blood cells usually burst every 48-72 hours. Each time they burst, you will have a bout of fever, chills and sweating.

Malaria can also be spread through blood transfusions and the sharing of needles, but this is very rare.

Antimalarial medication 

Antimalarial medication is used to prevent and treat malaria.

You should always consider taking antimalarial medicine when travelling to areas where there is a risk of malaria. Visit your GP or local travel clinic for malaria advice as soon as you know when and where you are going to be travelling.

It is very important that you take the correct dose and that you finish the course of antimalarial treatment. If you are unsure, check with your GP or pharmacist how long you should take your medication for.

Preventing malaria

It is usually recommended you take antimalarial tablets if you are visiting an area where there is a malaria risk because they can reduce your risk of malaria by about 90%.

The type of antimalarial tablets prescribed will be based on the following information you give:


where you are going

any relevant family medical history

your medical history, including any allergies to medication that you have

any medication that you are currently taking

any problems that you have had with antimalarial medicines in the past

your age

whether you are pregnant (see below)


You may need to take a short trial course of antimalarial tablets before travelling. This is to check that you don't have an adverse reaction or side effects. If you do, alternative antimalarials can be prescribed before you leave.

Types of antimalarial medication

The main types of antimalarials used to prevent malaria are described below.

Atovaquone plus proguanil


Dosage – the adult dose is one adult-strength tablet a day. Child dosage is also once a day, but the amount depends on the child’s weight. It should be started one or two days before your trip, taken every day that you are in a risk area and for seven days after you return.

Recommendations – a lack of clear evidence means that this antimalarial should not be taken by pregnant or breastfeeding women. It is also not recommended for people with severe kidney problems.

Possible side effects – stomach upset, headaches, skin rash and mouth ulcers.

Other factors – it can be more expensive than other antimalarials so may be more suitable for short trips.


Doxycycline (also known as Vibramycin-D)


Dosage – the dose is 100mg daily as a tablet or capsule. You should start the tablets two days before you travel, take them each day you are in a risk area and for four weeks after you return.

Recommendations – not suitable for pregnant or breastfeeding women, children under the age of 12 (due to the risk of permanent tooth discolouration), people who are sensitive to tetracycline antibiotics or people with liver problems.

Possible side effects – sunburn due to light sensitivity, stomach upset, heartburn and thrush. It should always be taken with food, preferably when standing or sitting. Doxycycline reduces the effectiveness of combined hormone contraceptives, such as the contraceptive pill or contraceptive patches.

Other factors – if you take doxycycline for acne, it will also provide protection against malaria as long as you are taking an adequate dose (ask your GP). Doxycycline is relatively cheap.


Mefloquine (also known as Lariam)


Dosage – the adult dose is one tablet weekly. Child dosage is also once a week but the amount will depend on the child’s weight. It should be started three weeks before you travel, taken all the time you are in a risk area and for four weeks after you get back.

Recommendations – it is not recommended if you have epilepsy, seizures, depression or other mental health problems, or if a close relative has any of these conditions. It is not usually recommended for people with severe heart or liver problems.

Possible side effects – dizziness, headache, sleep disturbances (insomnia and vivid dreams) and psychiatric reactions (anxiety, depression, panic attacks and hallucinations). It is very important to tell your doctor about any previous mental health problems, including mild depression. Do not take this medication if you have a seizure disorder.

Other factors – if you have not taken mefloquine before, it is recommended that you do a three-week trial before you travel to see whether you develop any side effects.


Chloroquine and proguanil

A combination of antimalarial medications called chloroquine and proguanil is also available, although these medications are rarely recommended nowadays because they are largely ineffective against the most common (particularly in Africa) and dangerous type of malaria parasite called Plasmodium falciparum.

However, chloroquine and proguanil may occasionally be recommended for certain destinations where the Plasmodium falciparum parasite is less common than other types, such as India and Sri Lanka.

Treating malaria

If malaria is diagnosed and treated promptly, a full recovery can be expected. Treatment should be started as soon as a blood test confirms malaria.

Many of the same antimalarial medicines used to prevent malaria can also be used to treat malaria. However, if you have taken an antimalarial to prevent malaria, you should not take the same one to treat malaria if you still become infected. Therefore, it is important to tell the doctor treating you the name of the tablets that you took to help prevent infection.

The type of antimalarial medicine and how long you need to take it will depend on:


the type of malaria you have

where you caught malaria

the severity of your symptoms

whether you took preventative antimalarial tablets

your age

whether you are pregnant


Your doctor may recommend using a combination of different antimalarials to overcome strains of malaria that have become resistant to single types of medication.

Antimalarial medication is usually given as tablets or capsules. If someone is very ill, it will be given through a drip into a vein in the arm (intravenously) in hospital.

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

Emergency standby treatment

Before you travel, you may be prescribed an emergency course of antimalarial medicine if there is a risk of you becoming infected with malaria while travelling in a remote area where there is little or no access to medical care.

Examples of medications that may be prescribed to treat malaria in an emergency include atovaquone with proguanil, artemether with lumefantrine, quinine plus doxycycline and quinine plus clindamycin.

Your GP may decide to seek advice from a travel health specialist before prescribing emergency standby treatment.

Antimalarials in pregnancy

If you are pregnant, it is advisable to avoid travelling to areas where there is a risk of malaria.

Pregnant women have an increased risk of developing severe malaria and both the baby and mother could experience serious complications.

If you are pregnant and unable to postpone or cancel your trip to an area where there is a malaria risk, it is very important that you take the right antimalarial medicine.

Some of the antimalarials used to prevent and treat malaria are unsuitable for pregnant women because they can cause side effects for the mother and her baby.

The list below outlines which medications are safe or unsafe to use while pregnant:


Mefloquine isn't usually prescribed during the first trimester of pregnancy, or if pregnancy is a possibility during the first three months after preventative antimalarial medication is stopped. This is a precaution even though there is no evidence to suggest that mefloquine is harmful to an unborn baby.

Doxycycline is never recommended for pregnant or breastfeeding women because it could harm the baby.

Atovaquone plus proguanil is generally not recommended during pregnancy or breastfeeding because research into their effects is limited. However, if the risk of malaria is high, they may be recommended if there is no suitable alternative.


Chloroquine combined with proguanil is suitable during pregnancy, but it is rarely used because it is not very effective against the most common and dangerous type of malaria parasite.

Complications of malaria 

Malaria is a serious illness which can be fatal if not diagnosed and treated quickly, particularly in pregnant women, babies, young children and the elderly.

The Plasmodium falciparum parasite causes the most severe malaria symptoms and most deaths.

As complications of severe malaria can occur within hours or days of the first symptoms, it is important to seek urgent medical help as soon as possible.

Anaemia

The destruction of red blood cells by the malaria parasite can cause severe anaemia.

Anaemia is a condition where the red blood cells are unable to carry enough oxygen to the body's muscles and organs, leaving you feeling drowsy, weak and faint.

Cerebral malaria

In rare cases, malaria can affect the brain. This is known as cerebral malaria and it can cause your brain to swell, sometimes leading to permanent brain damage. It can also cause seizures (fits) or coma (a state of unconsciousness).

Other complications

Other complications that can arise due to severe malaria include:


liver failure and jaundice (yellowing of the skin and whites of the eyes)

shock (a sudden drop in blood pressure)

pulmonary oedema (a build-up of fluid in the lungs)

acute respiratory distress syndrome (ARDS)

abnormally low blood sugar (hypoglycaemia)

kidney failure

swelling and rupturing of the spleen

dehydration


Malaria in pregnancy

The World Health Organization (WHO) recommends that pregnant women should avoid travelling to areas where there is a risk of malaria.

If you get malaria while pregnant, you and your baby have an increased risk of developing serious complications, such as:


premature birth (birth before 37 weeks of pregnancy)

low birthweight

restricted growth of the baby in the womb

stillbirth

miscarriage

death of the mother


Visit your GP if you're pregnant and travelling to a high-risk area. They may recommend that you take antimalarial medication. 

Preventing malaria 

There is a significant risk of getting malaria if you travel to an affected area. It is very important you take precautions to prevent it.

Malaria can often be avoided using the ABCD approach to prevention which stands for:


Awareness of risk – find out whether you are at risk of getting malaria.

Bite prevention – avoid mosquito bites by using insect repellent, covering your arms and legs and using a mosquito net.

Check whether you need to take malaria prevention tablets – if you do, make sure you take the right antimalarial tablets at the right dose, and finish the course.

Diagnosis – seek immediate medical advice if you have malaria symptoms, including up to a year after you return from travelling.


These are outlined in more detail below.

Being aware of the risks

To check whether you need to take preventative malaria treatment for the countries you are visiting, see the Fit for Travel or the National Travel Health Network and Centre (NaTHNaC) websites.

It's also important to visit your GP or local travel clinic for malaria advice as soon as you know where you are going to be travelling.

Even if you grew up in a country where malaria is common, you still need to take precautions to protect yourself from infection if travelling to a risk area. No-one has complete immunity to malaria and any level of natural protection you may have had is quickly lost when you move out of a risk area.

Preventing bites

It is not possible to avoid mosquito bites completely but the less you are bitten, the less likely you are to get malaria.

To avoid being bitten:


Stay somewhere that has effective air conditioning and screening on doors and windows. If this is not possible, make sure that doors and windows close properly.

If you are not sleeping in an air-conditioned room, sleep under an intact mosquito net that has been treated with insecticide.

Use insect repellent on your skin and in sleeping environments. Remember to re-apply it frequently. The most effective repellents contain DEET (diethyltoluamide) and are available in sprays, roll-ons, sticks and creams.

Wear light loose-fitting trousers rather than shorts, and wear shirts with long sleeves. This is particularly important during early evening and at night, when mosquitoes prefer to feed.


There is no evidence to suggest that homeopathic remedies, electronic buzzers, vitamins B1 or B12, garlic, yeast extract spread (such as Marmite), tea tree oils or bath oils offer any protection against mosquito bites.

Antimalarial tablets

There is currently no vaccine available that offers protection against malaria, so it is very important to take antimalarial medication to reduce your chances of getting malaria.

However, antimalarials only reduce your risk of infection by about 90%, so taking steps to avoid bites is also important.

When taking antimalarial medication:


Make sure you get the right antimalarial tablets before you go (check with your GP or pharmacist if you are unsure). 

Follow the instructions included with your tablets carefully.

Continue to take your tablets for up to four weeks (depending on the type you are taking) after returning from your trip to cover the incubation period of the disease.


Check with your GP to make sure you are prescribed a medication you can tolerate. You may be more at risk from side effects if you:


have HIV or AIDS

have epilepsy or any type of seizure condition

are depressed or have another mental health condition

have heart, liver or kidney problems

take medicine, such as warfarin, to prevent blood clots

use combined hormonal contraception, such as the contraceptive pill or contraceptive patches


If you have taken antimalarial medication in the past, don't assume that it is suitable for future trips. The antimalarial you need to take will depend on which strain of malaria is carried by the mosquitoes and whether they are resistant to certain types of antimalarial medication.

In the UK, chloroquine and proguanil can be bought over the counter from local pharmacies, although you should seek medical advice before buying it because it is rarely recommended nowadays. For all other antimalarial tablets, you will need a prescription from your GP.

Get immediate medical advice

If you become ill while travelling in an area where malaria is found or after returning from travelling, you must seek medical help straight away – even if you have been taking antimalarial tablets.

Malaria can get worse very quickly, so it's important that it is diagnosed and treated as soon as possible.

If you develop symptoms of malaria while still taking antimalarial tablets (either while you are travelling or in the days and weeks after you return), remember to tell the doctor which type you have been taking. The same type of antimalarial should not be used to treat you as well.

If you develop symptoms after returning home, visit your GP or a hospital doctor and tell them which countries you have travelled to in the last 12 months, including any brief stopovers.



DEET insect repellents

The chemical DEET (diethyltoluamide) is often used in insect repellents.

It is not recommended to be used for babies who are less than two months old.

DEET is safe for older children, adults and pregnant women if you follow the manufacturer’s instructions:


Use on exposed skin.

Do not spray directly onto your face, spray into your hands and pat onto your face.

Avoid contact with lips and eyes.

Wash your hands after applying.

Do not apply to broken or irritated skin.

Make sure you apply DEET after applying sunscreen, not before

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