Malaria infection

Last reviewed: 7 Jun 2022
Last updated: 06 Jul 2022



History and exam

Key diagnostic factors

  • fever or history of fever
More key diagnostic factors

Other diagnostic factors

  • headache
  • weakness
  • myalgia
  • arthralgia
  • anorexia
  • diarrhea
  • seizures
  • nausea and vomiting
  • abdominal pain
  • pallor
  • hepatosplenomegaly
  • jaundice
  • altered level of consciousness
  • hypotension
  • anuria/oliguria
Other diagnostic factors

Risk factors

  • travel to endemic area
  • inadequate or absent chemoprophylaxis
  • insecticide-treated bed net not used in endemic area
  • settled migrants returning from travel to endemic area of origin
  • low host immunity (for severe disease)
  • pregnancy (for severe disease)
  • age <5 years (for severe disease)
  • immunocompromise (for severe disease)
  • older age (for severe disease)
  • iron administration (children)
More risk factors

Diagnostic investigations

1st investigations to order

  • Giemsa-stained thick and thin blood smears
  • rapid diagnostic tests (RDTs)
  • CBC
  • clotting profile
  • serum electrolytes, BUN and creatinine
  • serum LFTs
  • serum blood glucose
  • urinalysis
  • arterial blood gas
More 1st investigations to order

Investigations to consider

  • polymerase chain reaction (PCR) blood for malaria
  • chest x-ray
  • blood culture
  • urine culture
  • sputum culture
  • lumbar puncture
  • HIV test
  • PCR nasopharyngeal swabs for influenza
  • CT head
More investigations to consider

Emerging tests

  • loop-mediated isothermal amplification

Treatment algorithm


Plasmodium falciparum: uncomplicated disease, able to take oral medication initially

Plasmodium falciparum: severe disease or unable to take oral medication initially

Plasmodium ovale

Plasmodium vivax

Plasmodium malariae or Plasmodium knowlesi


Plasmodium falciparum: recurrent infection



Ron Behrens, MD, FRCP

Honorary Consultant in Tropical and Travel Medicine

Hospitals for Tropical Diseases

Professor emeritus

London School of Hygiene and Tropical Medicine




RB has acted as a paid expert to the courts on malaria prophylaxis. RB has received fees on the Travel Health advisory board for Emergent BioSolutions. RB had prepared education material for the Royal College of Physicians and Surgeons of Glasgow. RB is an author of a number of references cited in this topic.


Dr Ron Behrens would like to gratefully acknowledge Mariyam Mirfenderesky, Dr Signe Maj Sorensen, Dr Joanna Allen, Dr Simon Warren, and Dr Behzad Nadjm, previous contributors to this topic.


MM, SMS, JA, and SW declare that they have no competing interests. BN is an author of a reference cited in this topic.

Peer reviewers

Blaise Genton, MD


Head of the Travel Clinic

Consultant of Tropical and Travel Medicine

University Hospital

Project leader

Swiss Tropical and Public Health Institute




BG has received a research grant from Novartis Pharma to assess the impact of the introduction of artemether-lumefantrine (Novartis) as first-line treatment for uncomplicated malaria on mortality of children under 5 years old in 2 districts in Tanzania and travel grants from Novartis Pharma to present the results of the study above. BG is an author of a reference cited in this topic.

David Sullivan, MD

Associate Professor

Malaria Research Institute and Department of Molecular Microbiology and Immunology

Johns Hopkins Bloomberg School of Public Health




DS has received royalties from antigen provision for a diagnostic test to Inverness. DS with Johns Hopkins University has patents on diagnostic tests that do not require blood.

Walther H. Wernsdorfer, MD


Institute of Specific Prophylaxis and Tropical Medicine

Medical University of Vienna




WHW declares that he has no competing interests.

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