When viewing this topic in a different language, you may notice some differences in the way the content is structured, but it still reflects the latest evidence-based guidance.

Last reviewed: 21 Mar 2025
Last updated: 10 Aug 2023

Summary

Definition

History and exam

Key diagnostic factors

  • presence of risk factors
  • fever
  • constitutional symptoms
  • conjunctival injection
  • relative bradycardia (Faget's sign)
  • biphasic illness
  • haemorrhagic diathesis
  • signs of renal failure
  • signs of hepatic failure
  • jaundice

Other diagnostic factors

  • hypotension
  • abdominal pain, vomiting, and lethargy

Risk factors

  • residence in, or recent travel to, endemic area
  • lack of immunisation
  • mosquito bite
  • travel during rainy and early dry seasons

Diagnostic investigations

1st investigations to order

  • FBC
  • liver function tests
  • coagulation screen
  • reverse transcription polymerase chain reaction (RT-PCR)
  • serology

Emerging tests

  • virus isolation
  • isothermal nucleic acid amplification assays

Treatment algorithm

Contributors

Authors

William A. Messer, MD, PhD

Associate Professor of Medicine

Department of Molecular Microbiology and Immunology

Division of Infectious Diseases

Oregon Health & Science University

Portland

PortlandOR

Disclosures

WAM declares that he has no competing interests.

Acknowledgements

Dr William A. Messer would like to gratefully acknowledge Dr Philip A. Yeon and Dr Helmut Albrecht, previous contributors to this topic.

Disclosures

PAY and HA declares that he has no competing interests.

Peer reviewers

Carlos Franco-Paredes, MD, MPH

Assistant Professor

Emory University

TravelWell Clinic

Emory University Hospital Midtown

Atlanta

GA

Disclosures

CFP declares that he has no competing interests.

Andrea K. Boggild, MSc, MD, DTMH, FRCPC

Clinical Assistant

Tropical Diseases Unit

Division of Infectious Diseases

Department of Medicine

Toronto General Hospital

University Health Network

Toronto

Canada

Disclosures

AKB declares that she has no competing interests.

Use of this content is subject to our disclaimer