Symptoms of malaria

Malaria is a tropical disease spread by mosquitoes that can be fatal if it is not diagnosed quickly and treated effectively. Malaria infection occurs when you are bitten by a mosquito - typically a female Anopheles mosquito - that is carrying one of 5 different types of the parasite plasmodium (a common strain is plasmodium falciparum). The parasite enters your bloodstream and - depending on which type you have been infected with - it can multiply, causing serious symptoms (and in some cases, death). Certain strains can also remain in your body for years, leading to relapses.

People who travel to countries with high-risk malaria zones are putting themselves in danger of contracting the disease, which is why it’s important to take precautions before leaving. The best way to protect yourself against malaria is to take malaria tablets such as Malarone or Doxycycline, wear insect repellent containing DEET, wear long-sleeved clothing, and familiarise yourself closely with malaria symptoms, so that - if you are infected - you can quickly seek out medical help.

What are the symptoms of malaria?

Malaria has an incubation period of seven to 18 days (depending on the type of plasmodium causing the infection), meaning it may take almost three weeks for symptoms to become apparent. In some cases, it can even take as long as a year - although this is rare.

The shortest incubation period (typically 7 to 14 days) occurs with plasmodium falciparum, widely accepted to be the most dangerous of the malarial parasites. The longest incubation period (typically 18 to 40 days) occurs with plasmodium malariae.

Early malaria symptoms are flu-like, and often begin with an attack of shivering, followed by a fever and profuse sweating. After this can follow:

• headache
• chills
• fatigue
• vomiting
• diarrhoea
• night sweats

One recognisable characteristic of malaria is that the fever symptoms are sometimes cyclical (due to the life cycle of the parasite), meaning that they can seem to pass for a few days before commencing again. Typically, an attack of malaria symptoms recurs every 48 hours before passing again. This aspect of malaria can help significantly with diagnosis, and distinguish it from other diseases such as typhoid fever.

What a typical episode of malarial fever looks like

• The patient shivers and feels cold for an hour.
• The patient develops a fever and headache, which last for around 6 hours.
• The patient sweats profusely for 2 to 4 hours as their temperature drops. They are left feeling weak and exhausted, and fall asleep soon after.

These bouts of fever can continue for weeks or months if left untreated, and in some cases can recur later in life. Malaria can also lead to potentially fatal complications, which require urgent treatment at a hospital.

Symptoms of severe malaria

Severe malaria is usually caused by the parasite plasmodium falciparum. If not treated within 24 hours of infection, this type of malaria can lead to serious health problems and, in many cases, death.

Plasmodium falciparum infects red blood cells, causing them to stick to the blood vessel walls. This in turn causes the blood vessels to become blocked, preventing the flow of blood to vital organs. This can lead to life-threatening conditions such as:

• cerebral malaria
• anaemia
• kidney failure
• abnormal liver function
• low blood sugar
• “Blackwater fever”, caused by the malaria parasite breaking down red blood cells, leading to the release of haemoglobin into the blood vessels and urine.

As a result of these conditions, severe malaria symptoms can include:

• convulsions (fits)
• difficulty breathing
• exhaustion
• confusion
• severe dehydration
• yellowish eyes, mouths or palms
• dark, reddish urine

Any person suffering these symptoms will need urgent medical attention.

How is malaria treated?

Treatment of non-severe malaria

In most cases, malaria can be treated at home using prescription-only anti-malarials such as atovaquone with proguanil and mefloquine. Chloroquine is another medicine associated with the treatment of malaria, however it has become ineffective in treating the plasmodium falciparum strain, which has developed a resistance to it.

It may be that your doctor prescribes you a combination of anti-malarials, specific to the strain that you have been infected with. If you are infected with plasmodium vivax or plasmodium ovale, for instance, you will require additional treatment (such as primaquine) to stop the recurrence of the disease in later life.

Treatment of severe malaria

Severe malaria that has been caused by plasmodium falciparum must be treated in a hospital. The standard treatment for this strain in the UK is quinine, injected directly into your bloodstream, followed by an anti-malarial such as atovaquone with proguanil. A patient suffering from this strain will also probably need to have their kidneys, lungs and blood sugar levels monitored due to the health complications that can accompany it.

Malaria prevention

The best way to avoid malaria infection is to take anti-malarial tablets before travelling to any high-risk destination (visit the NHS Fit For Travel site for a full, up-to-date list of at-risk areas).

You will typically take anti-malarial tablets once a day, starting about 2 days before you arrive at your destination (mefloquine is an exception to this). Atovaquone with proguanil only needs to be taken for a week after you return from the at-risk area, while other types of tablet must be taken for longer. There are some side effects associated with malaria tablets, including nausea and diarrhoea, and most types are generally unsuitable for pregnant or breastfeeding women to take - unless her doctor deems that the benefit of the tablets will outweigh the risks.

It is possible to contract malaria even if you are taking anti-malarial tablets. If you develop any symptoms suggestive of malaria up to a year after travelling to a malaria-affected area then you should seek urgent medical advice.You should also protect yourself against getting bitten by a mosquito in the first place by wearing long-sleeved clothes, using insect repellent and sleeping inside a mosquito net.

For more information on malaria symptoms and treatments, consult the NHS website, or speak to your doctor.

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