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Malaria

Overview
 

Malaria is a tropical disease passed on to humans by mosquitoes, and is present in over 100 countries. Malaria is spread by the female of the Anopheles species of mosquito. When one of these mosquitoes bites you, it feeds on your blood and injects malaria parasites into your body. It only takes one bite to infect you. In some forms of malaria, parasites can stay dormant in your body for years, occasionally "waking up" and causing you to have more attacks of malaria. However, you can’t catch malaria from another person, just from a mosquito.

 

There are four types of malaria:

 

  1. Plasmodium falciparum (malignant)
  2. Plasmodium vivax (benign)
  3. Plasmodium ovale (benign), and
  4. Plasmodium malariae (benign).

They’re all dangerous, but Plasmodium falciparum is considered to be the most serious. It’s responsible for most malaria fatalities. It can sometimes take a year or more for symptoms of Plasmodium vivax and ovale to appear, while Plasmodium falciparum usually starts within three months of being bitten.

Occasional isolated outbreaks have been reported in England, particularly by airport workers, and those who have contact with items imported from other countries. Altogether, around 2,000 cases of malaria are brought into the UK each year.

Malaria predominantly affects countries in Africa, South and Central America, Asia and the Middle East. The disease is particularly widespread in sub-Saharan Africa, where over 90% of malaria-related deaths occur.

Almost two thirds of all malaria-related deaths occur among the poorest 20% of the world's population.

In 1998 the World Health Organisation (WHO), UNICEF, World Bank and the United Nations Development Programme (UNDP) joined forces to fund the Roll Back Malaria programme. Roll Back Malaria aims to halve malaria-related deaths by 2010.

Complications

Malaria can potentially be a very serious illness and, in some cases, it can be fatal. The falciparum strain of the plasmodium parasite causes the most severe malaria symptoms and results in the most fatalities.

Anaemia

The extensive destruction of your red blood cells can leave you with severe anaemia. Anaemia is a condition where the red blood cells are unable to carry enough oxygen, which can leave you feeling lethargic, weak and faint.

Cerebral malaria

In some rare cases of malaria, the infected red blood cells can block the small blood vessels leading to the brain. This is known as cerebral anaemia and can cause your brain to swell which, in some cases, may lead to permanent brain damage. It can also cause you to have a seizure (a sudden attack of illness, where your muscles may involuntary contract), or to fall into a coma.

Some other complications of a severe case of malaria can include:

  • breathing problems (such as fluid in your lungs),
  • dehydration,
  • liver failure,
  • shock,
  • spontaneous bleeding,
  • ,jaundice (a yellow discolouration of the skin caused by an excess of a chemical in your blood called bilirubin),
  • hypoglycaemia (an abnormally low amount of sugar in your blood),
  • kidney failure, and
  • swelling, and rupturing, of the spleen.


Complications of malaria tend to be more severe in pregnant women and children.
 

Causes

Malaria is caused by a type of parasite (an organism that lives and feeds off another organism) known as plasmodium. There are hundreds of different types of plasmodium, but only four of them cause malaria in humans.

The four types of plasmodium parasite include:

  • Plasmodium falciparum - this is the only malignant form of malaria, and is predominantly found in Africa. This parasite causes the most severe symptoms and results in the most fatalities.
  • Plasmodium vivax - a benign type of parasite found mainly in Asia. It produces less severe symptoms than plasmodium falciparum, but can stay in the liver for up to three years, which can result in relapses of the condition.
  • Plasmodium ovale - a benign parasite that is usually found in Africa. This type of parasite can stay in your blood for several years without producing any symptoms.
  • Plasmodium malarie - this benign parasite is relatively rare and is usually only found in West Africa.


How does the parasite spread?

The plasmodium parasite is usually transmitted by a particular species of mosquito, known as the anopheles mosquito. If a female of the species bites a person infected with malaria, the mosquito can then carry the parasite and spread it to others when it bites and feeds from a person's blood.

When the plasmodium parasite enters your blood stream, it travels to the liver and then re-enters the blood stream where it is able to invade red blood cells. Eventually, the infected red blood cells burst and, when they do, they release even more of the tiny parasites into the blood. The infected cells tend to burst every 48-72 hours. Each time they burst, you will usually experience an attack of chills, fever and sweating.

Pregnancy and malaria

Research suggests that if you are pregnant, you are more at risk of catching malaria than normal. This is because your immune system can be weaker during pregnancy, which means your body is less able to fight off bacteria and infection. If you are pregnant and have malaria, you may pass the infection on to your baby. See the 'treatment' section for details of the malaria medicines that are safe to use during pregnancy.
 

Diagnosis
 

If you’re abroad and you start showing symptoms which could be malaria, get to your nearest doctor or hospital as quickly as you can. You will probably need to give a blood sample to check for parasites.

If you start showing symptoms when you’re back home, make sure you tell your GP or hospital doctor that you’ve just returned from a malarial area because some doctors in the UK may not be familiar with the disease.

 

To make a preliminary diagnosis of malaria, your GP will ask you about your symptoms and look at your travel history. It is important that you tell your GP about where you have travelled to in the last 12 months, including places where you only made a brief stop over.

After the preliminary diagnosis, you will have a blood sample taken in order to confirm the condition. A small amount of blood is taken and mixed with a special solution before being analysed under a microscope. This test will be able to confirm the presence of malaria, and will also indicate to your GP what type of parasite is causing your condition.

Treatment

Malaria can be a potentially fatal condition, but with a prompt diagnosis and treatment, many people make a full recovery. If you have been diagnosed with malaria, your treatment will start as soon as possible.

Malaria is normally treated using anti-malarial medicines. The type of medicine that you are prescribed, and the length of your treatment, will depend on a number of factors, such as:

  • the type of malaria that you have contracted,
  • where you were infected,
  • whether or not you are pregnant,
  • your age, and
  • the severity of your symptoms.


There are five drugs commonly used to treat malaria. Your doctor will check the most recent advice and tell you which one is right for you. Depending on the current situation in your destination, they may recommend a combination of different drugs to overcome strains of malaria which have become drug-resistant.

Atovaquone plus proguanil (brand name Malarone)
This drug is not recommended for pregnant or breastfeeding women, babies, and small children under 24lb, or people with severe kidney problems. Dosage for adults is one tablet a day, which can be started just one to two days before your trip and finished a week after you get back. Side effects include headaches and abdominal pain.

Chloroquine (brand names Avloclor, Nivaquine)
Not recommended for people with liver or kidney problems, eye or vision problems, psoriasis, epilepsy or porphyria, or people taking other medications. Adults will need to take one dose per week, starting one week before you go and carrying on for four weeks after you return. Side effects include nausea, headaches, diarrhoea and abdominal cramps. Chloroquine is one of the oldest malaria drugs, so some strains of malaria are resistant to it.

Doxycycline (brand names Nordox and Vibramycin)
Doxycylcline is not suitable for pregnant or breast-feeding women, children under 12, people who are sensitive to tetracycline antibiotics or people with liver problems. Dosage is one tablet a day, starting one or two days before you go and carrying on for four weeks after you return. Side effects include nausea and diarrhoea.

Mefloquine (brand name Lariam)
Not recommended for babies under 11lb, people who have had epilepsy or psychiatric problems, or people with heart problems. Dosage is one tablet a week starting three weeks before you go, and carrying on for four weeks after you get back. Side effects include dizziness, headaches, insomnia, nightmares, anxiety, depression, panic attacks and hallucinations. Very rarely, there may be fits or psychatric problems needing treatment. It’s very important that you tell your doctor about any previous psychiatric problems, including depression.

Proguanil (brand name Paludrine) plus chloroquine
This combination is not suitable for people with liver or kidney problems. Dosage is two tablets per day, starting one week before you go and ending four weeks after you return. Side effects include mouth ulcers, indigestion, nausea and vomiting. Chloroquine is usually taken in combination with proguanil.

If you have a mild case of malaria, you may be prescribed medication that you can take at home. If your malaria is more severe, you may have to be admitted to hospital. If you are unable to take your medication orally, you may have to have your anti-malarial medicine administered intravenously (through a vein in your arm).

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

Treatment during pregnancy

If you are pregnant, some of the medicines that are usually used to treat malaria are unsuitable because they may cause side effects for both you and your child. Chloroquine and quinine are the medicines that are safe to use during pregnancy. These can be used at any stage of your pregnancy without harm to you, or your baby. However, if you were prescribed these medicines as a way of preventing malaria, they will not be suitable as a form of treatment for the disease.

Other medicines may be suitable depending on which stage of your pregnancy you are at. If you develop any malaria-like symptoms, or suspect that you may be at risk of malaria, contact your GP as soon as possible.
 

Symptoms
 

Symptoms of malaria tend to appear between 10 days to 4 weeks after the initial bite. However, in some cases, depending on the type of parasite you are infected with, it can take a year before your symptoms start to show.

Benign malaria

Symptoms of benign malaria are similar to flu symptoms and can include:

  • fever (with a temperature up to 40°C),
  • chills,
  • generally feeling unwell,
  • muscular aches,
  • headaches,
  • diarrhoea,
  • nausea, and
  • vomiting.


These symptoms can last for several weeks if no medication is taken, but usually disappear within a few days with proper treatment.

Malignant malaria

Malignant malaria is caused by a parasite called plasmodium falciparum. Malignant malaria usually begins with similar symptoms to benign malaria, but will often lead to you developing further complications, such as breathing problems, fits, liver failure and shock. (see 'complications' section). Malignant malaria can also affect the brain and central nervous system. If it