National case definition: Viral hemorrhagic fever

Date of last revision/review: May 2008

National notification

This section includes the case definition for viral hemorrhagic fevers, which includes Lassa (Arenaviridae), Crimean Congo, Rift Valley fever (Bunyaviridae), Ebola and Marburg (Filoviridae).

Confirmed, probable and suspect cases of disease should be notified.

Contact the Public Health Agency of Canada immediately using the 24-hour emergency line 1-800-545-7661 even in the event of a suspected case.

Type of surveillance

Routine case-by-case notification to the federal level

Case classification

Confirmed case

Suspect or probable case with laboratory confirmation of infection:

or

One of the above criteria plus laboratory confirmation using at least one of the following:

or

Isolation of virus from an appropriate clinical specimen (blood, serum, tissue, urine specimens or throat secretions)

Probable case

Clinical evidence of illness and a history within the three weeks before onset of fever of one of the following:

Suspect case

Clinical evidence of illness

Laboratory comments

Any testing related to suspected VHF should be carried out under level 4 containment facilities (NML) because of issues of security, expertise and personnel vaccination.

Contact the Public Health Agency of Canada immediately using the 24-hour emergency line (1-800-545-7661), even in the event of a suspected case, in order to activate the ERAP program.

Clinical evidence

Crimean Congo VHF: Acute viral illness consisting of sudden onset of fever, malaise, generalized weakness, anorexia, irritability, confusion, headache and pain in the limbs and groin. Fever generally lasts 5-12 days and is followed by a prolonged convalescent phase. Acute symptoms are usually accompanied by flushing, conjunctival injection and petechial or purpuric rash involving mucosal surfaces, chest and abdomen. Vomiting, abdominal pain and diarrhea are occasionally seen. Bleeding may be seen from gums, nose, lungs, uterus and GI tract. There is often thrombocytopenia, mild hematuria and proteinuria, and evidence of hepatic involvement. Severe cases may be associated with liver failure.

Lassa VHF: Acute viral illness lasting one to four weeks. Gradual onset of symptoms, including fever, headache, generalized weakness, malaise, sore throat, cough, nausea, vomiting, diarrhea, myalgia, and chest and abdominal pain. Fever may be persistent or intermittent. Inflammation and exudation of the pharynx and conjunctivae is commonly observed. Many cases are mild or asymptomatic. Severe cases may result in hypotension, shock, pleural effusion, hemorrhage, seizures, encephalopathy and proteinuria, resulting in edema of the face and neck.

Ebola and Marburg VHF: Severe acute viral illness consisting of sudden onset of fever, malaise, myalgia, headache, conjunctival injection, pharyngitis, vomiting and diarrhea that can be bloody. It is often accompanied by a maculopapular or petechial rash that may progress to purpura. Bleeding from gums, nose, injection sites and GI tract occurs in about 50% of patients. Dehydration and significant wasting occur as the disease progresses. In severe cases, the hemorrhagic diathesis may be accompanied by leucopenia; thrombocytopenia; hepatic, renal and central nervous system involvement; or shock with multi-organ dysfunction.

Rift Valley VHF: Human infections with Rift Valley fever are usually associated with a brief, self-limited febrile illness. Most patients experience sudden onset of fever, malaise, severe myalgias with lower back pain, chills, headache, retro-orbital pain, photophobia and anorexia. Fever usually lasts for four days. In a minority of patients, fever returns after two or three days accompanied by return of symptoms as well as flushed face, nausea, vomiting and injected conjunctivae. Severe disease is associated with bleeding, shock, anuria and icterus. Enchepalitis and retinal vasculitis can also occur.

ICD code(s)

ICD-10 code(s)

ICD-9 code(s)

Type of international reporting

Under Article 6 of the International Health Regulations (IHR) (2005), each State Party shall notify the World Health Organization (WHO) by way of the IHR National Focal Point,Footnote 1 and within 24 hours of assessment of public health information, of all events which may constitute a public health emergency of international concern within its territory in accordance with the decision instrument (Annex 2 of the IHRFootnote 2), as well as any health measure implemented in response to those events.

Note: If event does not meet the criteria for notification under Article 6 of the IHR, then other IHR-related reporting requirements may still apply with WHO and/or other States Parties, including those under Art. 7 (information-sharing during unexpected or unusual public health events), Art. 8 (consultation with WHO on public health events), Art. 9 (any public health risk that may cause international disease spread), Art. 10 (requests for verification from WHO), and Art. 44 (collaboration and assistance).  

References

Health Canada. Case definitions for diseases under national surveillance. CCDR 2000;26(S3).
http://publications.gc.ca/collections/collection_2016/aspc-phac/HP3-1-26-S3-eng.pdf

World Health Organization. Department of Communicable Disease Surveillance and Response (October 1999). WHO Recommended Surveillance Standards. 2nd ed. WHO/CDS/CSR/ISR/99.2. Retrieved on May 9, 2007, from www.who.int/csr/resources/publications/surveillance/whocdscsrisr992.pdf

Peters CJ. Marburg and Ebola virus hemorrhagic fevers. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 6th ed. Vol 2. Philadelphia: Churchill Livingstone. Elsevier, 2006.

Watts DM, Flic R, Peters C, Shope RE. (2006). Bunyaviral fevers: Rift Valley fever and Crimean-Congo hemorrhagic fever. In: Guerrant RL, Walker DH, Weller PF. Tropical Infectious Diseases: Principles, Pathogens and Practice. 2nd ed. Philadelphia: Churchill Livingstone. Elsevier, 2006.

Enria D, Mills JN, Flick R et al. Arenavirus infections. In: Guerrant RL, Walker DH, Weller PF. Tropical Infectious Diseases: Principles, Pathogens and Practice. 2nd ed. Philadelphia: Churchill Livingstone. Elsevier, 2006.

Peters CJ, Zaki SR. Overview of viral hemorrhagic fevers. . In: Guerrant RL, Walker DH, Weller PF. Tropical Infectious Diseases: Principles, Pathogens and Practice. 2nd ed. Philadelphia: Churchill Livingstone. Elsevier, 2006.

World Health Organization. International Health Regulations (2005). 3rd ed. Geneva, 2016, from http://www.who.int/ihr/publications/9789241580496/en/

Footnotes

Footnote 1

In Canada, the IHR National Focal Point is located at the Public Health Agency of Canada.

Return to footnote 1 referrer

Footnote 2

IHR Annex 2 Decision Instrument is on pages 43-46 of the IHR Third Edition (2005): http://www.who.int/ihr/publications/9789241580496/en/.

Return to footnote 2 referrer

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