Malaria: symptoms, mosquito bite prevention, tests and treatment

Malaria is a serious illness spread by mosquito bites. This article explains how it spreads, the symptoms, tests and treatment, and how to protect yourself with bite avoidance and medicines advised by a doctor. It draws on the World Health Organization (WHO), the NHS and MedlinePlus.

1. Introduction

Malaria is a life-threatening disease spread to people by some types of mosquito. WHO explains that it is caused by a parasite (a tiny living organism that lives in another), and that it does not spread from one person to another in everyday contact ^[1]. It is mostly found in tropical countries ^[1]. The NHS says it is found in large areas of Africa and Asia, Central and South America, and some other regions ^[2].

WHO estimated 282 million malaria cases and 610 000 deaths worldwide in 2024 ^[1]. WHO says malaria can be prevented and treated, and that testing early matters because early symptoms look like other fevers ^[1]. The NHS warns that you can die from malaria if it is not diagnosed and treated quickly ^[2].

2. How malaria spreads

Malaria mostly spreads through the bite of infected female Anopheles mosquitoes. Rarely it can pass through blood transfusion or contaminated needles ^[1]. The NHS adds that it can rarely pass from a mother to her unborn baby, and that it can take just one bite to become infected ^[2].

Several parasite species cause malaria in people. WHO names P. falciparum as the deadliest and P. vivax as the main type in most countries outside sub-Saharan Africa ^[1]. Infants, children under 5, pregnant women, travellers and people with HIV or AIDS have a higher risk of severe illness ^[1]. The NHS also lists people over 65, people with a weak immune system and people without a spleen ^[2]. Someone who grew up in a high-risk country but now lives elsewhere may no longer be immune ^[2].

3. Signs and symptoms

Early symptoms can be mild and look like other fevers, which is why testing matters ^[1]. WHO lists fever, headache and chills as the most common, usually starting 10 to 15 days after the bite ^[1]. The NHS describes a wider range ^[2]:

• A high temperature, or feeling hot, cold or shivery
• Sweating and headaches
• Feeling very tired and sleepy, especially in children
• Feeling or being sick, tummy pain and diarrhoea
• Loss of appetite and muscle pains
• Yellow skin or eyes (jaundice), which may be harder to see on brown or black skin
• Sore throat, cough or difficulty breathing

The NHS says symptoms usually appear 7 to 18 days after a bite, but sometimes not for months after travel, and rarely for years ^[2]. MedlinePlus notes that a blood test can diagnose malaria ^[3].

Severe malaria can cause extreme tiredness, confusion or reduced awareness, repeated convulsions (seizures), difficulty breathing, dark or bloody urine, jaundice and abnormal bleeding ^[1]. WHO says untreated P. falciparum malaria can become severe and fatal within 24 hours ^[1].

4. Diagnosis and tests

WHO recommends that every suspected case is confirmed with a parasite-based test, either by looking at blood under a microscope or with a rapid diagnostic test ^[1]. Because malaria can look like other fevers, WHO says testing early matters ^[1]. MedlinePlus says a blood test can diagnose it ^[3].

5. Treatment

Malaria is always treated with medicine ^[1]. The NHS calls it an emergency that needs treatment quickly, and some people need to stay in hospital for specialist care ^[2]. WHO says doctors choose the medicine based on the type of malaria, whether the parasite resists a medicine, the person's age or weight, and whether they are pregnant ^[1]. Some types, such as P. vivax, can come back later and need additional medicine to prevent relapse ^[1]. The NHS notes malaria can sometimes return and need treatment again ^[2].

6. Prevention

Malaria can be prevented by avoiding mosquito bites and, for travellers, with preventive medicines ^[1]. Steps named by WHO, the NHS and MedlinePlus include ^{[1, 2, 3]}:

• Sleep under insecticide-treated mosquito nets
• Use a mosquito repellent on skin, especially after dusk
• Wear long sleeves and trousers in the evening when mosquitoes are most active
• Use window screens, coils or vaporisers
• See a doctor before travelling about preventive medicines

WHO advises asking a doctor several weeks before departure, as some preventive medicines must be started 2 to 3 weeks before travel, taken on schedule and continued for 4 weeks after leaving the risk area ^[1]. The NHS suggests seeking advice 4 to 6 weeks before travel ^[2]. WHO also reports that vaccines are recommended for children in regions with moderate to high transmission of P. falciparum malaria, and that they work best alongside nets and other measures ^[1].

7. When to see a doctor

See a doctor urgently if you have fever or other malaria symptoms after being in a place where malaria occurs. The NHS advises urgent medical advice if symptoms appear within 12 months of travel to a malaria area, and getting help while still travelling rather than waiting to get home ^[2]. The NHS also says to tell anyone you travelled with to get help straight away if they have symptoms ^[2].

Severe symptoms such as confusion, convulsions, difficulty breathing, dark or bloody urine or jaundice need emergency care ^[1]. In an emergency, call your local emergency number (112 in India, 911 in the United States).

8. Conclusion

Malaria is spread by mosquito bites and needs prompt testing and medical treatment. Preventing bites, taking preventive medicines as advised by a doctor and seeking help quickly for any fever after travel to a malaria area are the most important steps.