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Viral Haemorrhagic Fevers (Quarantinable)

Queensland Health Guidelines for Public Health Units

Revision History

 Version  Date  Changes
 1.0 June 2011 Full revision of guideline.

Infectious Agent

A range of different viruses cause haemorrhagic fevers. While mostly zoonotic and/or vector-borne, some (including Lassa, Ebola, Marburg, and Crimean-Congo haemorrhagic fever) can spread from person to person causing serious illness, hence their inclusion on the list of quarantinable diseases under the Commonwealth Quarantine Act (1908).

This guideline only applies to viral haemorrhagic fevers caused by the following viruses:

  • Ebola virus and Marburg virus (filoviruses)
  • Lassa virus (an arenavirus)
  • Crimean-Congo haemorrhagic fever virus (a bunyavirus)

Notification Criteria

Laboratory definitive evidence
Laboratory definitive evidence requires confirmation by the Special Pathogens Laboratory, CDC, Atlanta, or the Special Pathogens Laboratory, National Institute of Virology (NIV), Johannesburg.

  1. Isolation of a viral haemorrhagic fever virus
    OR
  2. detection of specific virus by nucleic acid testing, antigen detection assay, or electron microscopy
    OR
  3. IgG seroconversion or a significant increase in antibody level or a fourfold or greater rise in titre to specific virus.

Laboratory suggestive evidence

  1. Isolation of virus pending confirmation by CDC, Atlanta or NIV, Johannesburg
    OR
  2. detection of specific virus by nucleic acid testing, antigen detection assay, or electron microscopy pending confirmation by CDC, Atlanta or NIV, Johannesburg
    OR
  3. IgG seroconversion or a significant increase in antibody level or a fourfold or greater rise in titre to specific virus pending confirmation by CDC, Atlanta or NIV, Johannesburg
    OR
  4. detection of IgM to a specific virus.

Clinical evidence
A compatible clinical illness as determined by an infectious disease physician. Common presenting complaints are fever, myalgia and prostration, with headache, pharyngitis, conjunctival injection, flushing, gastrointestinal symptoms. This may be complicated by spontaneous bleeding, petechiae, hypotension and perhaps shock, oedema and neurologic involvement.

Epidemiological evidence

  1. History of travel to an endemic/epidemic area within 13 days (Crimean-Congo) or 21 days (Lassa, Ebola, Marburg) of illness onset
    OR
  2. contact with a confirmed case
    OR
  3. exposure to viral haemorrhagic fever (VHF)-infected blood or tissues.

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Notification Procedure

Pathology Laboraties

To notify urgently (i) on request for examination and (ii) on diagnosis by telephone or facsimile.

Attending Medical Practitioners/Medical Superintendents (or delegates)
To notify urgently on clinical suspicion by telephone or facsimile.

The public health unit should immediately notify the Chief Quarantine Medical Officer (Senior Director, Communicable Diseases Branch) who will liaise with the Director of Human Quarantine (Chief Medical Officer, Australian Department of Health and Ageing) as required.

Reporting to NOCS

Report both confirmed and probable cases.

Confirmed case

A confirmed case requires laboratory definitive evidence only.

Probable case

A probable case requires laboratory suggestive evidence AND clinical evidence AND epidemological evidence.

Objectives of Surveillance

To identify cases so that appropriate measures can be taken to prevent further transmission.

Public Health Significance and Occurence

Disease due to Lassa, Marburg and Ebola viruses is largely restricted to Africa. Crimean-Congo haemorrhagic fever virus is more widely distributed: Africa, the Mediterranean, the Middle East, Eastern Europe, central Asia, China and the Indian subcontinent. The most common VHF is Lassa fever, usually from West Africa. About 80% of Lassa infections are mild or asymptomatic. However, all four viruses can cause outbreaks with high case fatality rates.

One recovered case of Lassa fever was diagnosed in a rural hospital in NSW in 1985. An outbreak of Marburg virus disease occurred in Europe in 1967 linked to imported African green monkeys. Laboratory acquired cases of Ebola occurred in Russia and the United States in 2004. Prior to 2004, fewer than 20 cases of VHF had been diagnosed in the USA, the most recent being in 1976. A subtype of Ebola has caused illness in cynomolgus monkeys imported from the Philippines, and human infection without illness.

Travel is a potent factor in the emergence of infections and the current volume, speed and distance of travel are unprecedented. This has increased the risk that persons infected with a VHF may be diagnosed in Australia.

While many VHFs were initially considered to be highly communicable between humans, this concept has not been substantiated. Although nosocomial transmission has occurred in areas with endemic disease, accumulated evidence suggests that transmission of these viruses does not commonly occur through casual or remote contact. Several importations to non-endemic countries have occurred without subsequent disease outbreaks.

VHFs are designated quarantinable diseases. Ultimate responsibility for surveillance, treatment and control lies with the Australian Department of Health and Ageing under the Quarantine Act 1908. All costs incurred in treating a patient with a quarantinable disease are borne by the Australian Government.

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Clinical Features

Severe acute viral illnesses, usually with sudden onset of fever, malaise, myalgia and headache, followed by pharyngitis, vomiting and diarrhoea. In severe and fatal forms, the haemorrhagic diathesis is often accompanied by hepatic damage, renal failure, CNS involvement and terminal shock with multi-organ dysfunction. Because of the non-specific clinical symptoms and high case fatality rate, it is important that the diagnosis is made and treatment instituted as early as possible. Viral haemorrhagic fevers should be considered in the differential diagnosis of every patient with an unexplained fever who has travelled during the preceding three weeks to an area with endemic or epidemic transmission.

Reservoir

Lassa virus - wild rodents.

Crimean-Congo haemorrhagic fever - believed to be hares, birds, rodents and ticks. Domestic and wild animals may act as amplifying hosts. Ticks are the vector for the disease.

Ebola and Marburg viruses - despite exhaustive studies, reservoir remains unknown, although increasing evidence suggests a role for non-human primates and/or bats.

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Mode of Transmission

Lassa fever

  • Aerosol or direct contact with excreta of infected rodents on surfaces or in food or water.
  • Person to person by sexual contact, inoculation with blood or contact with urine or pharyngeal secretions.
  • Laboratory-acquired and nosocomial infections occur.

Crimean-Congo haemorrhagic fever

  • Bite of infective adult tick, or through crushing tick.
  • Contact with infected blood or tissues.

Ebola haemorrhagic fever

  • Infection of index case seems to occur while handling infected wild mammals.
  • Person to person transmission occurs by direct contact with infected blood, secretions, organs or semen.
  • Risk is highest during the late stages of illness, when the patient is vomiting, having diarrhoea or haemorrhaging, and during funerals with unprotected body preparation.
  • Airborne transmission has not been documented.
  • Nosocomial infection is common.

Marburg haemorrhagic fever

  • Risk factors for Marburg transmission are less well understood.

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Incubation Period

Lassa: commonly 6 - 21 days

Ebola: 2 - 21 days

Marburg: 2 - 21 days

Crimean-Congo: Usually 1 - 3 days, maximum 9 days (if tick vector); 5-6 days, maximum 13 days (if acquired from contact with infected blood or tissues).

Period of Communicability

Lassa fever

  • Person to person spread may theoretically occur during the acute febrile phase when virus is present in secretions and excretions.
  • Virus may be excreted in urine for 3 - 9 weeks from onset of illness.
  • Transmission through semen has occurred up to 3 months after infection.

Ebola and Marburg haemorrhagic fevers

  • Not before the febrile phase and increasing with stages of illness, as long as blood and secretions contain virus.
  • Transmission of Ebola through semen has occurred 7 weeks after clinical recovery and Ebola virus has been isolated from seminal fluid on the 61st but not on the 76th day after onset of illness.

Crimean-Congo haemorrhagic fever
Crimean-Congo haemorrhagic fever virus period of communicability is unknown.

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Susceptibility and Resistance

All ages are susceptible; the duration of immunity following infection is unknown.

Management

Suspected Cases

Risk assessment and categorisation

Suspected cases of VHF may be categorised into three risk groups.

High risk
Anyone who has been in rural areas or towns where VHF is known to be endemic or epidemic, and becomes ill within 21 days of leaving such areas.

  • Medical and nursing staff who have cared for VHF cases within the past 21 days.
  • Contacts of confirmed cases who become ill within 21 days of exposure.
  • Laboratory workers who become ill within 21 days of handling specimens, cultures or other dangerous materials from suspect or confirmed cases of VHF.

Medium risk

  • Anyone who has been in rural areas or towns where it is thought that VHF could be present, but not definitively known, and becomes ill within 21 days of leaving such areas.

Low risk

  • Anyone who has briefly visited major cities in tropical Africa.
  • Anyone becoming ill more than 21 days after contact with a potential source of
    infection or having left an infected area.

Investigation
In consultation with the attending medical practitioner, consider other differential diagnoses; urgent exclusion of malaria is necessary.

Other major differential diagnoses include:

  • dengue
  • typhoid fever
  • leptospirosis
  • septicaemia (meningococcal, staphylococcal or streptococcal)
  • amoebiasis
  • plague
  • Q fever
  • relapsing fever
  • typhus.

The pathologist in charge of the laboratory must be informed that the differential diagnosis includes VHFs. He/she will assume responsibility for ensuring urgent tests are performed using suitable precautions. Provided universal laboratory precautions are followed, all tests required for acute patient care should be made available locally. Clinicians should consult with the relevant public health physician/quarantine medical officer to discuss risk stratification, potential source of infection, isolation, and other public health measures.

Cases

Testing
Confirmatory testing for VHFs can be organised through the Special Pathogens Laboratory, CDC, Atlanta.

Treatment
Early treatment with ribavirin has been used with success in Lassa fever cases.

Restriction
The patient should be nursed in a single room with an anteroom and strict isolation and infection control procedures should be in place.

These rooms need separate ventilation or preferably should be at negative pressure. A single room in an intensive care unit (ICU) may also be needed, and has the same ventilation requirements. All persons entering the patient's room should wear gloves and gowns to prevent contact with items or environmental surfaces that may be soiled. P2 (N 95) respirators and eye protection should be worn by persons coming within one metre of the patient to prevent contact with blood, body fluids or secretions (including respiratory droplets). Appropriate disinfection of all body substances and objects with which the case has had contact including laboratory equipment.

To reduce infectious exposure, laboratory tests should be kept to a minimum. Laboratories should consult the guidelines Laboratory Precautions for Samples Collected from Patients with Suspected Viral Haemorrhagic Fevers.

Dead bodies should be sealed in leak-proof material and cremated or buried promptly in a sealed casket. Post-mortem examination should not normally be carried out.

Wherever possible, high or medium-risk patients should be transferred to the Royal Brisbane and Women’s Hospital (RBWH).

Counselling
The case should be advised of the nature of the infection and its mode of transmission, including the likelihood of sexual transmission (Marburg, Ebola and Lassa). Blood must not be donated. Male cases should refrain from unprotected sexual activity until the semen has been shown to be free of virus or for 3 months, whichever is later.

Contacts

Contact Tracing
Yes (for confirmed and probable cases)

Definition
A contact is defined as a person who has been exposed to an infected person or to an infected person’s secretions, excretions or tissues within three weeks of the patient’s onset of illness.

Contacts may be categorised into 3 levels of risk:

Casual contacts are people who have not had close personal contact with the infected person, eg. people on the same airplane, in the same hotel or, visitors to the patient’s home. Since the agents of VHF are not usually spread by such contact, no special surveillance is indicated unless the infected person had acute respiratory involvement with intense sneezing and coughing. In such situations, casual contacts should be treated as “close contacts”.

Close contacts are people who have had more than casual contact with the infected person before the initiation of isolation procedures. Close contact includes living in the same household; nursing, serving, hugging or having skin-to-skin contact; and handling laboratory specimens from the infected person before the diagnosis was suspected and isolation procedures were implemented. Close contacts should be identified if VHF is considered to be a likely diagnosis for the infected person and placed under the same surveillance as “high risk contacts” as soon as the diagnosis is confirmed.

High risk contacts are those with a history of either mucous membrane contact with the patient (kissing, sexual intercourse), or needle-stick or other penetrating injuries or broken skin contaminated with blood or other body fluids from the patient during their infectious period.

Investigation
Search for unreported or undiagnosed cases.

As soon as VHF is considered to be a likely diagnosis in the index patient, high risk contacts should be quarantined or placed under quarantine surveillance (ie. kept under surveillance for 3 weeks provided they undertake to notify the public health physician/ quarantine medical officer if suffering from a febrile illness) and temperatures should be recorded twice daily. Any contact who develops a temperature of >38 °C, or any other symptoms of illness, should be immediately hospitalised, isolated and treated as a VHF patient.

Prophylaxis
Ribavirin (500 mg by mouth every six hours for seven days) should be prescribed as post-exposure prophylaxis for high-risk contacts of Lassa fever cases. Although experience is limited, post-exposure prophylaxis with ribavirin is also recommended for high-risk contacts of patients with Crimean-Congo haemorrhagic fever.

Restriction
Contacts may be quarantined or released under quarantine surveillance.

Counselling
Explain the modes of transmission, reasons for, and likely duration of quarantine.

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Summary

Prepare a summary report of the investigation for the Communicable Diseases Branch, Queensland Health, on request.

References

Contingency Plan for Public Health Management of Viral Haemorrhagic Fever within Western Australia, Revised September 2007. Accessed 19/05/11.

European Network for Diagnostics of Imported Viral Diseases Scientific Advisory Committee, May, 2001. Management and Control of Viral Haemorrhagic Fevers and other highly contagious viral pathogens. Accessed 19/05/11.

Haemorrhagic Fevers, Viral. World Health Organisation. Accessed 19/05/11.

Heymann D (Ed), 2008. Control of Communicable Diseases Manual, 19th edition. American Public Health Association: Washington.

Viral Haemorrhagic Fevers. Centre for Disease Control and Prevention: Atlanta. Accessed 19/05/11.

Viral Hemorrhagic Fevers (VHFs) Contingency Plan – Ontario, January 2002. Accessed 19/05/11.

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Last updated: 17 September 2013