Viral Haemorrhagic Fever

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Management and Control of Viral Haemorrhagic Fevers
Summary of Guidance from the UK Advisory Committee on Dangerous Pathogens (Full UK documentation here)
The guidelines are designed to assist staff in Emergency Departments who may assess patients with unexplained pyrexia following a recent stay in countries where viral haemorrhagic fevers are endemic

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Viral Haemorrhagic Fevers

• Severe, life-threatening diseases caused by a range of viruses
• Restricted to Africa, parts of South America, rural parts of the Middle East and Eastern Europe
• The environment in Ireland does not support the natural reservoirs or vectors
• There is a risk of secondary infection - needlestick, through broken skin, mucous membranes
• 4 agents of VHF are of concern in Ireland because of possible person-to-person spread
  • Lassa
  • Ebola
  • Marburg
  • Crimean/Congo haemorrhagic fevers

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Lassa Fever	Primary infection in man probably occurs when broken skin or mucous membranes are exposed to the urine of the multi-mammate rat in Africa Variations in virulence have been observed in W Africa - mortality rates approach 60%
Ebola Fever	Cases in Zaire, Sudan, Cote D'Ivoire and Gabon Natural reservoir unknown (monkeys?) In 1995 an outbreak in Zaire mortality was 77% (>50% of those affected were hospital or home-based carers)
Marburg Fever	First described in laboratory workers in Germany - all had direct or indirect contact with body fluids from African green monkeys from Uganda Natural reservoir is unknown
Crimean/Congo HF	Transmission is by tick bite Virus is widespread in E and W Africa, Central Asia and the former USSR Antibodies have been detected in Dubai, Iraq, S Africa, Pakistan, Greece, Turkey, Albania, Afghanistan and India

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Incubation/symptoms

• Incubation periods for all these VHFs range from 3 - 21 days

• Symptoms

  • Fever (to 41C), malaise, headache, myalgia, arthralgia

  • Nausea, vomiting and diarrhoea

  • Ebola and Marburg often cause a morbilliform rash

  • Obvious bleeding is a late or terminal event

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Patient Assessment in ED

• VHF is possible in any patient with a PUO shortly after returning from overseas

• In most cases this can be dismissed on epidemiological grounds alone

• Most ill patients suspected of VHF will have malaria - tests for malaria should be undertaken ASAP (thin and HRP-2)

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Other causes of fever

Typhoid Dengue Rickettsial infections Tropical Parasites

The finding of malarial parasites does not exclude VHF. In moribund patients   -   Consider other diagnoses Diabetes Meningitis,   Stroke

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Categorisation of VHF risk

To provide efficient and timely management of patients with fever while affording maximum protection to staff

• Minimum Risk

  • Not been in endemic areas before the onset of the illness
    OR

  • Been in endemic areas (or in contact with a suspected source) onset of illness was definitely more than 21 days after their last contact with any potential source

• Moderate Risk

  • Been in endemic area during the 21 days before the onset of illness but no additional risk factors
    OR

  • Not been in an endemic area but who may have been in adjacent areas/countries who have evidence of severe illness/haemorrhage/organ failure

• High Risk

  • Stayed in houses where people were ill, feverish or suspected of VHF
  • Carers, laboratory staff who may have come into contact with patients, bodies or specimens where VHF is suspe

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Management 

Management - minimum risk

• May be admitted to a general hospital (standard isolation)

• If malaria excluded may remain at home

• Infection control team should be informed before the patient is admitted

• Patients may be transported by ambulance without special precautions

Management - moderate risk

• Discuss with micrtobiologist or Infectious diseases consultant

• In more than 95% of cases malaria will be the alternative diagnosis

• Initial malaria test may be carried out locally but other specimens should be sent to a High Security ID lab

• Ambulances will transport as a category III removal

Management - High Risk

• Admit to Hi Security ID unit

• Category III removal by ambulance

• Consultant in Communicable disease control should be informed

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Disinfection and decontamination

Fortunately viruses are not highly resistant to chemicals or heat - treat as other blood borne viruses such as hepatitis C and HIV

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Collecting Specimens

Obtaining and handling laboratory specimens is the most common cause of cases of VHF in health care settings

• Minimum risk - standard procedures

• Moderate/high risk - experienced staff, gown, waterproof apron, latex gloves, face mask, eye protection

• No lab work until a blood film has been examined for malaria parasites

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Samples for malaria films

• Dry cotton wool/gauze for pressure after venepuncture

• Use vacuum blood sampling system

• Specimen tubes labelled before

• Do not use finger prick for blood sampling

• Blood films should be dried and fixed

• Thick films should not be prepared

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Disposal of Equipment

• Blood taking equipment should be placed in a dedicated sharps box

• Gowns, gloves, etc should be 'double bagged' before incineration

• Other information

• Post mortem should not be performed

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Links

Triage / assessment form here Information on UK DoH guidelines for the management of suspected VHF cases is available here

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Content by Dr Jon Dallimore.   Published 24/07/2002.   Reviewqed by Dr ÍOS 03/03/2004, 16/03/05. Next review 16/03/2006

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