Epidemiological case definitions for Crimean-Congo haemorrhagic fever (CCHF)
For UKHSA use only: Epidemiological case definitions for CCHF.
What this guidance is for
Guidance for healthcare professionals on when to suspect Crimean-Congo haemorrhagic fever (CCHF) is available and should be the starting point for clinical assessment of a suspected case of CCHF.
This guidance describes the categorisation of possible, probable and confirmed cases of CCHF for use by health protection teams during a CCHF incident.
In this guidance, ‘body fluids’ can include blood, vomit, faeces, urine, saliva and semen.
For personal protective equipment (PPE) requirements for the management of CCHF cases, please see the ACDP Guidance on the Management of Patients with Viral Haemorrhagic Fever.
Any individual who has not had contact with a potential source of CCHF within the last 14 days before onset of illness is not deemed to be a possible or probable case of CCHF.
Case definitions
Confirmed case
An individual (alive or deceased) with a positive laboratory test result (real time polymerase chain reaction (PCR)) from a blood or other body fluid sample.
Probable case
An individual for whom no laboratory results are available (for example waiting for testing or results) where both of the following apply:
- clinical illness compatible with CCHF [note 1] comprising fever (temperature greater than 37.5C) with or without additional symptoms such as severe weakness, severe headache, myalgia, abdominal pain, vomiting, diarrhoea or unexplained haemorrhage
- history of direct contact with a probable or confirmed case of CCHF or their body fluids (including laboratory staff) in the 14 days before the onset of symptoms, without wearing adequate PPE or where there were breaches in PPE
Possible case
A deceased individual with epidemiological risk factors for CCHF [note 2]
or
An individual for whom no laboratory results are available (for example waiting for testing or results), where both the following apply:
- clinical illness compatible with CCHF [note 1], comprising fever (temperature greater than 37.5°C) with or without additional symptoms such as severe weakness, severe headache, myalgia, abdominal pain, vomiting, diarrhoea or unexplained haemorrhage
- history of direct contact with a confirmed case of CCHF or their body fluids (including laboratory staff) in the 14 days before the onset of symptoms, but wore appropriate PPE with no known breaches
Note 1. Initial symptoms may be not specific, but onset can be sudden with symptoms worsening over a few days, often with lethargy, rash, evidence of capillary leak, bleeding/haemorrhage, shock and impaired consciousness.
Note 2. Deceased individuals with an epidemiological link to the outbreak should be discussed with the Imported Fever Service (IFS) for consideration of post-mortem testing.