Crimean-Congo Hemorrhagic Fever outbreak toolbox

Crimean-Congo Hemorrhagic Fever outbreak toolbox

Updated | August 2024

Welcome to the Crimean-Congo Hemorrhagic Fever Outbreak Toolbox

Case definitions

WHO suggested outbreak case definition*

Suspected case

  • Any person with clinical features suggestive of CCHF1, and one or more of the following exposures in the 15 days before symptoms onset:
    • Bitten by a tick or crushed a tick with bare hands, OR 
    • Direct contact with animal blood or other tissues during/immediately after slaughter, OR 
    • Direct contact with blood, secretion or excretions of a CCHF case, OR 
    • Resided in or visited an endemic or outbreak-affected area, where exposure to livestock or ticks was possible.
Probable case
  • Any deceased suspected case (where it has not been possible to collect specimens for laboratory confirmation) with an epidemiological link with a confirmed CCHF case.
    • Confirmed case
  • Any suspected or probable case with a laboratory positive result (detection of virus by RT-PCR, positive IgM or IgG seroconversion2, positive antigen detection test, or virus isolation).
    • Discarded case
    • Any suspected or probable case with a negative laboratory result (showing no specific antibodies, RNA or specific detectable antigens).

    1.Signs and symptoms suggestive of CCHF commonly include: 

      • Sudden/abrupt onset of fever (>38°C), chills, shudders, myalgia, headaches dizziness, neck pain and stiffness, backache, headache, sore eyes and photophobia. There also may be nausea, vomiting, diarrhoea, abdominal pain, and sore throat early on, followed by sharp mood swings and confusion.
      • After 2–4 days, agitation may be replaced by sleepiness, depression and lassitude, abdominal pain may localize to the upper-right quadrant with detectable hepatomegaly, hepatitis, tachycardia, lymphadenopathy, and a petechial rash on the skin and internal mucosal surfaces (e.g., mouth, throat), ecchymoses, melena, haematuria, nose bleeding, and/or unusual vaginal bleeding. Severe cases may also experience rapid kidney deterioration, sudden liver failure or pulmonary failure.

    2. Rise in IgG antibody titers between acute and convalescent samples.

     

    Data collection tools

    • Case investigation forms: Not Available
    • Line list: Not available. 
    • Electronic tools: Not available 

    Training