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Agents (5) – Viral Haemorrhagic Fevers

Agents (5) – Viral Haemorrhagic Fevers. Part 8 of 13 Comments and contributions are encouraged: please e-mail DRcomments@hpa.org.uk. HPA Centre for Infections. Reviewed April 2009. Viral Haemorrhagic Fevers: Viruses. Several virus families: Filoviruses (Ebola, Marburg) Arenaviruses

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Agents (5) – Viral Haemorrhagic Fevers

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  1. Agents (5) – Viral Haemorrhagic Fevers Part 8 of 13 Comments and contributions are encouraged: please e-mail DRcomments@hpa.org.uk HPA Centre for Infections Reviewed April 2009

  2. Viral Haemorrhagic Fevers: Viruses Several virus families: • Filoviruses (Ebola, Marburg) • Arenaviruses (eg Lassa, Junin, Machupo) • Bunyaviruses (eg Crimean-Congo and Hanta HF, Rift Valley fever) • Flaviviruses (eg Yellow Fever, dengue) (CDC Public Health Image Library)

  3. Viral Haemorrhagic Fevers • Not all VHF viruses are transmissible by aerosol,or they are unlikely to be produced in high enough concentrations to be used as likely biological agents

  4. Viral Haemorrhagic Fevers:Signs & Symptoms • Variety of possible clinical manifestations and incubation periods depending on VHF agent • Incubation period varies from 2-21 days • Symptom onset may be abrupt (filoviruses) or more gradual (arenoviruses)

  5. Viral Haemorrhagic Fevers:Early Signs & Symptoms • Non-specific prodrome for up to 7 days, including: •  high fever  headache •  malaise  myalgia •  arthralgia  abdo pain •  nausea & vomiting +/or diarrhoea

  6. Viral Haemorrhagic Fevers:Clinical course • Initial • Cutaneous flushing or rash, conjunctival injection • Periorbital oedema • Positive tourniquet test • Hypotension • Later • Prostration • Pain (throat, chest, abdomen) • Bleeding & Shock

  7. Viral Haemorrhagic Fevers:Bleeding Manifestations • Ecchymoses (shown here in a patient with CCHF) are often accompanied by haemorrhage in other locations, e.g. epistaxis, haematemesis, melaena, haematuriaand atpuncture sites (Image courtesy of Professor R Swanepoel, NICD, South Africa)

  8. Viral Haemorrhagic Fevers:Outcome • Usually improving or moribund within a week (except Haemorrhagic Fever with renal syndrome [Hantavirus], arenaviruses) • Bleeding, CNS involvement, SGOT indicate poor prognosis • Mortality 10-90% (depends on virus)

  9. Viral Haemorrhagic Fevers: Differential Diagnosis • Bacterial • - Typhoid fever, meningococcaemia, rickettsioses, leptospirosis, toxic shock syndrome • Protozoal • - Falciparum malaria • Other • - Vasculitis, TTP, Haemolytic Uraemic Syndrome (HUS), heat stroke

  10. Viral Haemorrhagic Fevers: Diagnosis • Primarily clinical • Laboratory confirmation: • Enteric Respiratory and Neurological Virus Laboratory (ERNVL) HPA CfI or • Special Pathogens Reference Unit (SPRU) HPA CEPR • Antigen detection by PCR • Virus isolation • Acute (& convalescent) serum • Tissue

  11. Viral Haemorrhagic Fevers: Management • Negative pressure isolation if possible (but would depend on numbers affected) • Supportive care • Correct coagulopathies • No antiplatelet drugs or IM injections • Ribavirin possibly for • Arenaviruses (Lassa fever) • Bunyaviruses (CCHF)

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