Malaria is a very serious infection which you can catch from a bite from an infected mosquito. The most common symptoms are high temperature (fever) and a flu-like illness. The symptoms of malaria can occur even up to a year after travelling in an area in which malaria is present. Prompt treatment for malaria is essential, as without treatment it can be fatal. This leaflet gives general information about malaria and its treatment.
What is malaria?
Malaria is a serious infection. It is common in tropical countries such as parts of Africa, Asia and South America. It is caused by a parasite called plasmodium. A parasite is an organism that lives on an animal and feeds from it. The parasite is passed to humans from a mosquito bite.
There are four main types of plasmodium that cause malaria. These are called Plasmodium falciparum, Plasmodium vivax, Plasmodium ovale and Plasmodium malariae. Recently, another type has been discovered called Plasmodium knowlesi. Plasmodium falciparum is usually the most serious of the four.
Symptoms of malaria
- A very high temperature (fever).
- Breathing problems.
Symptoms of malaria usually occur between one to four weeks after the initial mosquito bite. However, in some cases, depending on the type of plasmodium you are infected with, it can take up to a year before any symptoms start to show. This means that you should suspect malaria in anyone with a feverish illness who has travelled to a malaria area within the previous year, especially in the previous three months.
There are two general types of malaria: benign and malignant. Benign malaria is milder and relatively easy to treat. Malignant malaria can be very severe and can sometimes be fatal.
The most common symptom of benign malaria is a very high temperature (fever). However, the absence of fever in an ill person does not exclude the diagnosis of malaria.
Other symptoms of benign malaria may include:
- Headaches, muscle pains, tummy (abdominal) pains, cough, feeling more tired than usual and feeling generally unwell.
- Children are more tired and can have runny stools (diarrhoea) and/or sickness (vomiting).
- If you have taken anti-malarial medication then you may have different symptoms (for example, backache) if you have malaria.
- The fever in most people has no specific pattern and may present 1-2 days after the symptoms start. If the malarial infection becomes established, then malarial symptoms can come in cycles, occurring every 2-3 days (see above).
Malignant malaria is caused by Plasmodium falciparum. Malignant malaria usually begins with similar symptoms to benign malaria. However, it will often lead to you developing further complications, such as breathing problems, liver failure and shock. Malignant malaria can also affect the brain and central nervous system, which can even lead to death.
Note: if you are pregnant then you are at particular risk of severe malaria and should, ideally, not go to malaria risk areas. This is because your immune system can be weaker during your pregnancy. If you are pregnant and have malaria, you may pass the infection on to your baby.
How common is malaria?
It was estimated that worldwide there were 214 million cases of clinical malaria in 2014 with nearly half of the world's population at risk of acquiring the infection. A total of 1,618 cases of imported malaria were reported in the UK in 2016. Most cases were caused by Plasmodium falciparum. Six UK deaths were associated with imported malaria in 2016.
Most UK infections occur in travellers returning to the UK (rather than visitors coming to the UK). The risk of getting malaria is greatest if you do not take your anti-malarial medication or do not take it properly. People who take last-minute holidays and also those visiting friends or relatives abroad have been shown to be the least likely to take their anti-malarial medication.
How is malaria transmitted?
The plasmodium parasite is usually transmitted by a particular species of mosquito, which is the anopheles mosquito. If a female anopheles mosquito bites a person who is infected with malaria, the mosquito can then carry the plasmodium parasite and spread it to others when it bites and feeds from other people's blood.
When the plasmodium parasite enters your blood, it travels to your liver and then re-enters the bloodstream where it can invade your red blood cells. Eventually, these infected red blood cells burst which leads to them releasing even more of the tiny parasites into your blood. These infected red blood cells tend to burst every 48-72 hours. Each time they burst, you will usually experience an episode of chills, high temperature (fever) and sweating.
How is malaria diagnosed?
If you think you may have malaria then you need to seek medical advice without delay. If you have travelled to an area in which there is malaria in the previous year then you may be at risk of this disease, even if you took anti-malarial medication when you were abroad.
Your doctor will perform a blood test. The blood sample will be sent to the laboratory and will be examined for the presence of the malaria parasite. The type of malaria causing the infection will also be determined. If the first blood test is negative but your doctor suspects you have malaria then you may be asked to have another blood test taken a couple of days later.
If malaria is promptly diagnosed and treated, most people make a full recovery. Malaria is normally treated using anti-malarial medicines. Quinine, chloroquine and artesunate are some of the different types of medicines available.
The type of medicine prescribed and the duration of treatment can vary from person to person. It depends on various factors such as:
- The type of malaria that you have.
- If you have taken any anti-malarial medication when you were travelling.
- The severity of your symptoms.
If your symptoms are mild then you will be treated at home. However, if you have Plasmodium falciparum malaria then it is very likely you will be treated and monitored in hospital.
Some people are given more than one type of medication or an alternative medication if they develop side-effects to a medication. Resistance to anti-malarial medicines has spread rapidly over the past few decades, especially resistance to Plasmodium falciparum. This means that newer medicines or a combination of medicines may be given.
If the first anti-malarial medicine that you are prescribed fails to improve your symptoms, you may have to try a variety of other medicines as part of your treatment. You may find that your treatment for malaria leaves you feeling very weak and tired for several weeks afterwards.
Travellers going to remote places far from medical facilities sometimes take emergency medication with them. This can be used to treat suspected malaria until proper medical care is available.
How can malaria be prevented?
There are a number of things that can protect you from malaria. Read more about malaria prevention.
Preventing malaria in four steps
There is an ABCD for prevention of malaria. This is:
- Awareness of risk of malaria.
- Bite prevention.
- Antimalarial medication - Chemoprophylaxis (taking antimalarial medication exactly as prescribed).
- Prompt Diagnosis and treatment.
Awareness of the risk of malaria
The risk varies between countries and the type of trip. For example, back-packing or travelling to rural areas is generally more risky than staying in urban hotels. In some countries the risk varies between seasons - malaria is more common in the wet season.
The main type of parasite and the amount of resistance to medication vary in different countries. Although risk varies, all travellers to malaria-risk countries should take precautions to prevent malaria.
The mosquitoes which transmit malaria commonly fly from dusk to dawn and therefore evenings and nights are the most dangerous time for transmission.
You should use an effective insect repellent on clothing and any exposed skin. Diethyltoluamide (DEET) is safe and the most effective insect repellent and can be sprayed on to clothes. It lasts up to three hours for 20%, up to six hours for 30% and up to 12 hours for 50% DEET. There is no further increase in duration of protection beyond a concentration of 50%. When both sunscreen and DEET are required, DEET should be applied after the sunscreen has been applied. DEET can be used on babies and children over 2 months of age. In addition, DEET can be used, in a concentration of up to 50%, if you are pregnant. It is also safe to use if you are breast-feeding. If you have sensitive skin you may find DEET irritating. Insecticides containing picaridin are a useful alternative.
If you sleep outdoors or in an unscreened room, you should use mosquito nets impregnated with an insecticide (such as pyrethroid). The net should be long enough to fall to the floor all around your bed and be tucked under the mattress. Check the net regularly for holes. Nets need to be re-impregnated with insecticide every six to twelve months (depending on how frequently the net is washed) to remain effective. Long-lasting nets, in which the pyrethroid is incorporated into the material of the net itself, are now available and can last up to five years.
If practical, you should try to cover up bare areas with long-sleeved, loose-fitting clothing, long trousers and socks - if you are outside after sunset - to reduce the risk of mosquitoes biting. Clothing may be sprayed or impregnated with permethrin, which reduces the risk of being bitten through your clothes.
Sleeping in an air-conditioned room reduces the likelihood of mosquito bites, due to the room temperature being lowered. Doors, windows and other possible mosquito entry routes to sleeping accommodation should be screened with fine mesh netting. You should spray the room before dusk with an insecticide (usually a pyrethroid) to kill any mosquitoes that may have come into the room during the day. If electricity is available, you should use an electrically heated device to vaporise a tablet containing a synthetic pyrethroid in the room during the night. The burning of a mosquito coil is not as effective.
Herbal remedies have not been tested for their ability to prevent or treat malaria and are therefore not recommended. Likewise, there is no scientific proof that homeopathic remedies are effective in either preventing or treating malaria and they are also not recommended.
Antimalarial medication (chemoprophylaxis) helps to prevent malaria. The best medication to take depends on the country you visit. This is because the type of parasite varies between different parts of the world. Also, in some areas the parasite has become resistant to certain medicines.
There is a possibility of antimalarials that you may buy in the tropics or over the internet, being fake. It is therefore recommended that you obtain your antimalarial treatment from your doctor's surgery, a pharmacist or a travel clinic. Medications to protect against malaria are not funded by the NHS. You will need to buy them, regardless of where you obtain them.
The type of medication advised will depend upon the area to which you are travelling. It will also depend on:
- Any health problems you have.
- Any medication you are currently taking.
- The length of your stay.
- Any problems you may have had with antimalarial medication in the past.
Names of medications often used are chloroquine, doxycycline, proguanil, atovaquone and mefloquine.
You should seek advice for each new trip abroad. Do not assume that the medication that you took for your last trip will be advised for your next trip, even to the same country. There is a changing pattern of resistance to some medicines by the parasites. Doctors, nurses, pharmacists and travel clinics are updated regularly on the best medication to take for each country.
You must take the medication exactly as advised. This usually involves starting the medication up to a week or more before you go on your trip. This allows the level of medicine in your body to become effective. It also gives time to check for any side-effects before travelling. It is also essential that you continue taking the medication for the correct time advised after returning to the UK (often for four weeks). The most common reason for malaria to develop in travellers is because the antimalarial medication is not taken correctly. For example, some doses may be missed or forgotten, or the tablets may be stopped too soon after returning from the journey.
What are the side-effects with antimalaria tablets?
Antimalarial medication is usually well tolerated. The most common side-effects are minor and include feeling sick (nausea) or diarrhoea. However, some people develop more severe side-effects. Therefore, always read the information sheet which comes with a particular medicine for a list of possible side-effects and cautions. To reduce possible side-effects, it is usually best to take the medication after meals.
If you are taking doxycycline then you need to use a high-factor sunscreen. This is because this medication makes the skin more sensitive to the effects of the sun.
Around 1 in 20 people taking mefloquine may develop headaches or have problems with sleep.
Further reading & references
- Malaria: guidance, data and analysis; Public Health England
- World Malaria Report; World Health Organization, 2012
- Malaria; NICE CKS, November 2016 (UK access only)
- Fairhurst RM, Nayyar GM, Breman JG, et al; Artemisinin-resistant malaria: research challenges, opportunities, and public health implications. Am J Trop Med Hyg. 2012 Aug;87(2):231-41.
- Malaria Reference Laboratory Website; Public Health England
Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. Patient Platform Limited has used all reasonable care in compiling the information but makes no warranty as to its accuracy. Consult a doctor or other healthcare professional for diagnosis and treatment of medical conditions. For details see our conditions.
Dr Colin Tidy
Dr Helen Huins