Malaria infection

Last reviewed: 25 Aug 2023
Last updated: 08 Aug 2023



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
  • bleeding
  • anuria/oliguria
  • tachypnea
Other diagnostic factors

Risk factors

  • travel to endemic area
  • inadequate or absent chemoprophylaxis
  • insecticide-treated bed net not used in endemic area
  • low host immunity (severe disease)
  • pregnancy (severe disease)
  • age <5 years (severe disease)
  • immunocompromise (severe disease)
  • older age (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



Elizabeth Ashley, MB BS, FRCP, FRCPath


Institution Lao-Oxford-Mahosot Hospital - Wellcome Trust Research Unit



Honorary Consultant in Infectious Diseases and Microbiology

Oxford University Hospitals NHS Foundation Trust

Professor of Tropical Medicine

University of Oxford




EA has active grants from a number of organizations; however, none of them are for malaria projects. EA is an associate editor of Malaria Journal, an academic editor for PLOS Medicine, and is on the Lancet Infectious Diseases International Advisory Board. EA is on the council of the International Society for Infectious Diseases and was paid by Pfizer to chair a grants committee on antimicrobial stewardship (unrelated to malaria). The Institution Lao-Oxford-Mahosot Hospital - Wellcome Trust Research Unit receives core funding from the Wellcome Trust. EA is an author of a number of references cited in this topic.

Arjun Chandna, BA MRCP AFHEA

Wellcome Trust Doctoral Training Fellow

Centre for Tropical Medicine and Global Health

University of Oxford


Specialty Registrar in Infectious Diseases and Medical Microbiology

University College London Hospitals NHS Trust






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


RB acted as a paid expert to the courts on malaria prophylaxis. RB received fees on the Travel Health advisory board for Emergent BioSolutions. RB 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. 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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