Malaria: migrant health guide
Source: gov.uk (2025-03-31)

Advice and guidance on the health needs of migrant patients for healthcare practitioners.

Main messages

Anyone visiting a malarious area can become infected regardless of age, sex, ethnicity or country of birth.

Malaria can be fatal if diagnosed late or left untreated. It is essential that all travellers take the correct precautions and recommended chemoprophylaxis for their visit.

Travellers visiting friends and relatives (https://www.gov.uk/guidance/travel-to-visit-friends-and-relatives-migrant-health-guide) in their countries of origin are at particularly high risk of malaria. Most malaria cases reported in the UK are in this group (https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/989677/Malaria_imported_into_the_United_Kingdom_in_2019.pdf) (PDF, 774KB), who often do not perceive themselves to be at risk, and may therefore not seek pre-travel advice.

To raise awareness, ask non-UK born patients from malarious countries whether they will be returning home to visit friends or relatives, and advise how and when they should seek travel advice.

Malaria is particularly dangerous for pregnant women. Some pregnant women may choose to travel back to their country of origin to be with family for their delivery. Women who intend to travel during pregnancy will need advice in relation to the health risks associated with this.

Always ask about history of travel when any patient presents with a fever. Malaria can present up to a year after the patient has been in a malarious area.

Malaria is a notifiable disease.

Background

Malaria is a febrile illness due to the infection of red blood cells with Plasmodium parasites.

Approximately half of the global population, many of whom live in the world’s poorest countries, are at risk of malaria, and around 230 million people are infected annually (https://www.who.int/en/news-room/fact-sheets/detail/malaria).

Malaria is very common: in parts of Africa the average person will have malaria several times a year.

In the UK, between 1,500 and 2,000 people are diagnosed with malaria each year, having acquired it abroad (https://www.gov.uk/government/collections/malaria-guidance-data-and-analysis).

In 2019, 73% of cases diagnosed in the UK were individuals born in Africa (https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/989677/Malaria_imported_into_the_United_Kingdom_in_2019.pdf) (PDF, 774KB), where country or region of birth information was known. 20% of cases were UK-born individuals.

Transmission

The parasite is transmitted through the bite of an Anopheles mosquito between dusk and dawn (https://www.who.int/en/news-room/fact-sheets/detail/malaria).

Malaria transmission rates are affected by local factors, such as:
- rainfall patterns
- proximity of mosquito breeding sites
- mosquito species
- time of day
Some regions have a fairly constant number of cases throughout the year, whereas in other regions transmission varies in intensity throughout the year, and highest rates usually coincide with the rainy season (https://www.who.int/news-room/fact-sheets/detail/malaria).

Types

There are 5 main types of malaria that affect humans (https://www.gov.uk/government/publications/malaria-prevention-guidelines-for-travellers-from-the-uk):

Plasmodium falciparum: causes the most malaria deaths worldwide (https://www.who.int/en/news-room/fact-sheets/detail/malaria) and accounts for around 86% of all cases in the UK.

Plasmodium vivax: less serious, but can cause relapsing malaria, and it accounts for around 4% of cases in the UK.

Plasmodium ovale: less common, but may also cause a relapsing disease, and accounts for around 7% of cases in the UK.

Plasmodium malariae: the least common form seen in the UK, but patients may present many years after infection.

Plasmodium knowlesi: very rarely imported, but can be severe.

Symptoms

Malaria should be considered in anyone with a fever, or history of a fever, who has recently returned from or previously visited a malaria endemic area in the last year, regardless of whether they have taken prophylaxis. Their temperature may be normal at the time of presentation (https://www.britishinfection.org/guidelines-resources/published-guidelines/).

Clinical presentations of malaria can vary, but features may include (https://www.gov.uk/government/publications/malaria-prevention-guidelines-for-travellers-from-the-uk):
- fever, sweats and/or chills
- malaise
- myalgia
- headache
- diarrhoea
- cough
Symptoms of severe or complicated falciparum malaria in adults:
- impaired consciousness or seizures
- renal impairment
- acidosis
- hypoglycaemia
- pulmonary oedema or acute respiratory distress syndrome (ARDS)
- low haemoglobin
- spontaneous bleeding/disseminated intravascular coagulation
- shock
- haemoglobinuria (without G6PD deficiency)
Symptoms of severe or complicated malaria in children:
- impaired consciousness or seizures
- respiratory distress or acidosis
- hypoglycaemia
- severe anaemia
- prostration
- hyperparasitaemia
Particular care must be taken in pregnant women from endemic countries, who may have malaria without typical symptoms. Anaemia should raise suspicion of malaria in this group.

See Malaria: guidance, data and analysis (https://www.gov.uk/government/collections/malaria-guidance-data-and-analysis).

Incubation period

The incubation period varies (https://www.gov.uk/government/publications/malaria-prevention-transmission-symptoms/malaria-transmission-incubation-period-symptoms#incubation-period) depending on the Plasmodium species involved (https://www.gov.uk/government/publications/malaria-prevention-transmission-symptoms/malaria-transmission-incubation-period-symptoms#incubation-period):

P. falciparum: 7 to 14 days, so most patients present within a month of exposure and almost all within 6 months of exposure

P. vivax and P. ovale: usually 12 to 18 days, but they can present months or years after return from a malarious area

Testing

Suspected malaria is a medical emergency (https://www.gov.uk/government/publications/malaria-prevention-guidelines-for-travellers-from-the-uk).

See the British Infection Association’s ‘UK malaria treatment guidelines’ (https://www.britishinfection.org/guidelines-resources/published-guidelines/) and ‘investigation and treatment of imported malaria in non-endemic countries (https://www.ncbi.nlm.nih.gov/pubmed/23693055) for further information.

Sample required for diagnosis: an EDTA-anti-coagulated venous blood sample.

Diagnosis of malaria by microscopic examination of thick and thin blood films will be performed by your haematology or microbiology department depending on local arrangements.

Blood tests

A blood sample should be taken and received in the laboratory within 1 hour (https://www.gov.uk/government/publications/malaria-prevention-guidelines-for-travellers-from-the-uk). There is no need to wait for fever spikes before taking blood.

All laboratories making a diagnosis of malaria should send blood films and a portion of the blood sample on which the diagnosis was made to the Malaria Reference Laboratory (https://www.gov.uk/government/collections/malaria-reference-laboratory-mrl) for confirmation.

Always include the travel history in the information provided on the test request form.

Blood film negative malaria

A diagnosis of malaria cannot be excluded on the basis of 1 negative blood film, so where malaria is suspected, blood films should be examined daily for 3 days while other diagnoses are also considered (https://www.gov.uk/government/publications/malaria-prevention-guidelines-for-travellers-from-the-uk).

If all 3 films are negative and malaria is still considered a possible diagnosis, seek expert advice from a specialist in tropical or infectious diseases.

It is particularly important to seek expert advice early in the care of pregnant patients with suspected malaria, since the parasite may be sequestered in the placenta resulting in negative peripheral blood films despite the patient having malaria.

Treatment

In the UK, malaria treatment is mainly undertaken by secondary care infectious disease specialists. The role of the primary care practitioner is to be vigilant for possible cases by always asking about travel history in patients with a fever and to ensure prompt testing and referral.

For further information, see UK malaria treatment guidelines (https://www.britishinfection.org/guidelines-resources/published-guidelines/).

Prevention

Malaria should be almost completely preventable if appropriate anti-mosquito and chemoprophylactic measures are taken.

The primary care practitioner has a vital role to play in ensuring that those at risk of acquiring malaria receive adequate information about how to protect themselves and in prescribing antimalarials as appropriate.

Country by country advice on malaria prevention is available from the National Travel Health Network and Centre (NaTHNaC) (https://travelhealthpro.org.uk/countries).

See Malaria prevention guidelines in travellers from the UK (https://www.gov.uk/government/publications/malaria-prevention-guidelines-for-travellers-from-the-uk).

Resources

Public Health England has developed a leaflet on malaria for people travelling overseas (https://www.gov.uk/government/publications/malaria-information-for-people-travelling-overseas), which is available in English, Bengali, Gujarati, Punjabi and Urdu.

NaTHNaC has produced travel health information sheets (https://travelhealthpro.org.uk/disease/113/malaria).

The Hospital for Tropical Diseases (http://www.thehtd.org/) is dedicated to the prevention, diagnosis and treatment of tropical diseases and travel related infections.

The Liverpool School of Tropical Medicine (https://www.lstmed.ac.uk/) and the associated Tropical and Infectious Disease Unit in the Royal Liverpool University Hospital provide advice on prevention, diagnosis and management of tropical infections.

NICE has published guidance via BNF about prophylaxis for malaria (https://bnf.nice.org.uk/treatment-summary/malaria-prophylaxis.html), including recommended regimens by country.

The Malaria Centre at the London School of Hygiene and Tropical Medicine (https://www.lshtm.ac.uk/research/centres/malaria-centre) conducts extensive research on malaria.

The WHO has further information on malaria (https://www.who.int/malaria/en/) and malaria reports (https://www.who.int/publications/i/item/9789240015791).

The Royal College of Obstetricians and Gynaecologists has published guidelines on the prevention of malaria in pregnancy (https://www.rcog.org.uk/en/guidelines-research-services/guidelines/gtg54a/).