Malaria Author: Rick M. Fairhurst, MD, PhD; Thomas E. Wellems, MD, PhD
Module updated - 2009-11-19
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Diagnosis
  • Use history to help distinguish malaria from other febrile infectious diseases.
  • Look for physical exam findings that suggest the diagnosis of malaria.
  • Use laboratory testing to confirm the diagnosis of malaria promptly.
  • Supplement blood smear exam with other rapid diagnostic testing.
  • Consider the broad differential diagnosis of malaria.
History and Physical Examination Elements for Malaria (table)
Laboratory and Other Studies for Malaria (table)
Differential Diagnosis of the Malaria Presentation (table)

Use history to help distinguish malaria from other febrile infectious diseases. C

  • Ask about symptoms that may be characteristic but not necessarily specific for malaria:
    • Cyclical paroxysms of rigors
    • Fever
    • Drenching sweats
  • Ask about symptoms that are usually not characteristic of malaria:
    • Productive cough
    • Profuse watery diarrhea
    • Allergic phenomena
  • Obtain a detailed travel history:
    • Geographic regions visited
    • Duration of visit
    • Type of lodging
    • Type of travel
    • Type of food and water ingested
    • Onset of symptoms in relation to first exposure to malarious area
    • Occurrence of insect bites
    • Illness in travel companions, which may indicate group exposure to pathogenic agents (e.g., enteric bacteria or schistosomes)
    • Sexual activity
  • Ask about antimalarial prophylaxis regimen:
    • Type of drug and dosage
    • Side effects
    • Compliance during travel
    • Premature discontinuation by traveler during the posttravel period
  • Ask about pretravel vaccinations:
    • Yellow fever
    • Salmonella typhi
    • Influenza
  • See table History and Physical Examination Elements for Malaria.
  • See figure Plasmodium Life Cycle, Recrudescence, and Relapse.
Background | Back to top


Look for physical exam findings that suggest the diagnosis of malaria. C

  • Look for:
    • Fever, typically acute onset, that may be cyclical or sustained
    • Pallor
    • Jaundice
    • Splenomegaly
    • Neurologic abnormalities, such as coma or seizure
  • Note that rash and lymphadenopathy are uncommon in malaria.
  • See table History and Physical Examination Elements for Malaria.
Background | Back to top


Use laboratory testing to confirm the diagnosis of malaria promptly. B

  • Obtain thick and thin diagnostic blood smears and have them read immediately by experienced personnel when the clinical presentation and travel history are compatible with malaria.
  • Determine the Plasmodium species and parasitemia of the blood sample.
  • Order pertinent laboratory tests to identify vital organ dysfunction consistent with severe malaria.
  • If the initial blood smear is negative and malaria remains possible, repeat the smear every 12 hours for at least 48 hours, but do not withhold empiric therapy until the smear is positive.
  • Report all blood-smear-positive cases of malaria diagnosed in the U.S. to the CDC using the Malaria Case Surveillance Form.
  • See table Laboratory and Other Studies for Malaria.
Background | Back to top


Supplement blood smear exam with other rapid diagnostic testing. B

  • Use rapid diagnostic tests when available to complement efforts at microscopic diagnosis of malaria.
  • Know the benefits and limitations of rapid diagnostic tests.
  • See table Laboratory and Other Studies for Malaria.
Background | Back to top


Consider the broad differential diagnosis of malaria. C

  • Focus on elements of the history and physical exam that tend to differentiate the signs of other febrile illnesses from malaria, because many febrile illnesses are associated with nonspecific constitutional symptoms.
  • Take a detailed history, including:
    • Travel itinerary
    • Activities
    • Exposures
    • Ill contacts
    • Insect bite precautions
    • Chemoprophylaxis regimen or stand-by antibiotic treatment
    • Pretravel vaccinations.
  • See table Differential Diagnosis of the Malaria Presentation.
Background | Back to top

FAQs
Harry Tagbor, MBChB, DrPH, editorial consultant, has no financial relationships with pharmaceutical companies, biomedical device manufacturers, or health-care related organizations. Rick M. Fairhurst, MD, PhD has no financial relationships with pharmaceutical companies, biomedical device manufacturers, or health-care related organizations. Thomas E. Wellems, MD, PhD has no financial relationships with pharmaceutical companies, biomedical device manufacturers, or health-care related organizations.
Steven E. Weinberger, MD, FACP, Acting Editor, PIER, has stock holdings in Glaxosmithkline and Abbott.

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