Public Health Agency of Canada Case Definition: Ebola virus disease outbreak

A person with EVD-compatible symptoms is defined as an individual presenting with fever (temperature ≥ 38.0 degrees Celsius) OR at least one of the following symptoms/signs:

• subjective fever
• malaise
• myalgia
• headache
• arthralgia
• fatigue
• loss of appetite
• conjunctival redness
• sore throat
• chest pain
• abdominal pain
• nausea
• vomiting
• diarrhoea that can be bloody
• haemorrhage
• erythematous maculopapular rash on the trunk

Epidemiological Risk Factors:

• Individual who cared for a case of Ebola Virus Disease (EVD)
• Laboratory worker handling Ebola virus or processing body fluids from a case of EVD
• Individual who spent time in a healthcare facility in an Ebola affected area where cases of EVD are being treated
• Sexual contact with an EVD case
• Close contact in households, healthcare facilities, or community settings with a person with Ebola while the person was symptomatic - close contact is defined as being for a prolonged period of time within approximately 2 meters (6 feet) of a person with Ebola
• Contact with any human remains of a case of EVD OR contact with human remains in an Ebola affected area
• Contact with bats, primates or wild animal bush meat from Ebola affected areas
• A travel history to an Ebola affected area within 21 days

Person Under Investigation (PUI)

A person with EVD-compatible symptoms (as defined above) AND

• A travel history to an Ebola affected area within 21 days of symptom onset OR exposure to one or more of the epidemiological risk factors (as defined above) within 21 days of symptom onset,
• With or without pending laboratory results for EVD.

Confirmed Case

A person with laboratory confirmation of EVD infection using at least one of the methods below:

• Isolation and identification of virus from an appropriate clinical specimen (e.g., blood, serum, tissue, urine specimens or throat secretions) (performed at the National Microbiology Laboratory) OR
• Detection of virus-specific RNA by reverse-transcriptase PCR from an appropriate clinical specimen (e.g., blood, serum, tissue) using two independent targets or two independent samples AND confirmed by the National Microbiology Laboratory by nucleic acid testing or serology OR
• Demonstration of virus antigen in tissue (e.g., skin, liver or spleen) by immunohistochemical or immunofluorescent techniques AND another test (e.g., PCR) OR
• Demonstration of specific IgM AND IgG antibody by EIA, immunofluorescent assay or Western Blot by the National Microbiology Laboratory or an approved WHO collaboration centre OR
• Demonstration of a fourfold rise in IgG titre by EIA, immunofluorescent assay from an acute vs. a convalescent serum sample (performed at the National Microbiology Laboratory).

A note on diagnostic testing and possible impacts of vaccination:

Diagnostic testing for Ebola virus using the molecular testing approaches of the National Microbiology Laboratory would not be impacted by recent vaccination. The molecular targets for this test (the Ebola virus NP and L genes) are not found in the rVSV-EBOV vaccine, which is based on the Ebola virus glycoprotein or GP gene. Testing in other countries may use the GeneXpert platform which uses the NP and GP genes as targets. As such it is conceivable that a recent vaccine recipient would be NP negative but GP positive. If the history of vaccination was not readily available, this could cause uncertainty. The gold standard for diagnosis remains being positive by two molecular targets, but a diagnostic result of singularly the GP gene would warrant repeat testing and other investigations. This would include re-testing and confirmation at the National Microbiology Laboratory. To note, serologic testing cannot currently distinguish between vaccinations and naturally acquired infections.