Malaria (Plasmodium falciparum): symptoms, prevention and urgent treatment

NICE Clinical Knowledge Summaries describe malaria as a life-threatening illness caused by infection of red blood cells by Plasmodium parasites, transmitted through the bite of infected female Anopheles mosquitoes. Several species infect humans. P. falciparum causes most deaths worldwide. P. vivax and P. ovale can lie dormant in the liver and cause relapses months or years later, P. malariae can cause lifelong chronic infection if untreated, and P. knowlesi, a parasite of monkeys in South-East Asia, can cause severe illness.

The NHS says malaria is common in tropical regions, including large areas of Africa and Asia, Central and South America, the Dominican Republic and Haiti, parts of the Middle East and some Pacific islands, and is not found in the UK. Rarely it can be passed from a mother to her unborn baby or by a needlestick injury.

The NHS says malaria can be hard to spot. Symptoms include a high temperature or feeling hot, cold or shivery, sweating, headaches and confusion, feeling very tired and sleepy (especially in children), feeling or being sick, tummy pain and diarrhoea, loss of appetite, muscle pains, yellow eyes or skin (jaundice), which may be less noticeable on brown or black skin, and a sore throat, cough and difficulty breathing.

NICE CKS stresses that clinical features are non-specific, that absence of fever does not exclude malaria, and that most missed infections are misdiagnosed as viral infections, flu, gastroenteritis or hepatitis. It advises suspecting malaria in anyone returning from or previously visiting a malaria area who is unwell or has a fever, regardless of tablets taken.

NICE CKS lists symptoms of severe malaria: reduced consciousness, seizures or being unable to stand or sit, kidney impairment, acidosis (which can cause fast, deep breathing), low blood sugar, breathing difficulty from fluid on the lungs, severe anaemia, spontaneous bleeding, shock, sepsis and very dark red urine in falciparum malaria. Any of these needs emergency care; call 999.

The NHS advises getting advice from a GP, nurse, pharmacist or travel clinic before going to a malaria area, ideally 4 to 6 weeks before, although last-minute advice is still worthwhile. You are still at risk if you now live in the UK but were born or used to live in a high-risk country, because you will no longer be immune.

Countermeasures listed by the NHS: take any prescribed antimalarial medicine, usually starting a few days or weeks before you go and continuing for a few weeks after you return; use 50% DEET-based insect repellent on skin; sleep under insecticide-treated mosquito nets; and wear long sleeves and trousers in the evening when mosquitoes are most active. Pregnant women, young children, people over 65, people with a weak immune system and people without a spleen are at higher risk of serious illness, and may be advised to avoid high-risk areas. The UK Malaria Expert Advisory Group publishes country-by-country guidance each year for UK travellers, which clinicians use.

• Check the risk for each country on TravelHealthPro before booking.

• Take the full course of tablets, including after returning.

• Antimalarial tablets and repellents reduce risk but do not remove it.

• Tell your doctor about travel to a malaria area for up to 12 months afterwards if you become unwell.

Malaria is diagnosed with blood tests that look for the parasite. NICE CKS says immediate hospital admission should be arranged for suspected severe or complicated malaria, suspected falciparum malaria, pregnant women, children and people older than 65. All other suspected cases should be discussed urgently with an infectious diseases specialist. All cases are notifiable to public health authorities.

The NHS says malaria is treated with antimalarial medicines, that some people need to stay in hospital for specialist care, and that malaria can sometimes come back and need treating again. NICE CKS says that if malaria is identified promptly, appropriate treatment is given and no organ dysfunction has occurred, most people make a rapid and complete recovery, whereas delayed or inappropriate treatment can lead to severe or fatal malaria.

Tell the clinician where you travelled and when, even if it was months ago and even if you took tablets. The NHS also advises that if you have symptoms, you should tell anyone you travelled with to get help straight away, since they were exposed at the same time. If you develop symptoms while abroad, seek medical advice there rather than waiting until you are home.