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Questions and Answers
What is a common initial symptom of most haemorrhagic fevers?
What is a common initial symptom of most haemorrhagic fevers?
Which factor significantly contributes to coagulation issues in patients with liver infection?
Which factor significantly contributes to coagulation issues in patients with liver infection?
How long can the incubation period for Lassa, Marburg, and Ebola viruses extend?
How long can the incubation period for Lassa, Marburg, and Ebola viruses extend?
Which of the following is NOT a symptom associated with severe forms of haemorrhagic fever?
Which of the following is NOT a symptom associated with severe forms of haemorrhagic fever?
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What is the typical clinical sign seen with dengue fever rash?
What is the typical clinical sign seen with dengue fever rash?
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What accompanies the transient rash often seen in Lassa haemorrhagic fever?
What accompanies the transient rash often seen in Lassa haemorrhagic fever?
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The phase of the illness where shock and multiple organ failure can occur typically occurs how many days after onset?
The phase of the illness where shock and multiple organ failure can occur typically occurs how many days after onset?
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What is a primary effect of macrophage infection in haemorrhagic fevers?
What is a primary effect of macrophage infection in haemorrhagic fevers?
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What is a mode of transmission for Hantaviruses?
What is a mode of transmission for Hantaviruses?
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Which of the following viruses can be transmitted from human to human?
Which of the following viruses can be transmitted from human to human?
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What role do insect vectors play in transmission?
What role do insect vectors play in transmission?
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What effect does a second dengue infection with a different serotype typically have on a patient?
What effect does a second dengue infection with a different serotype typically have on a patient?
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How long do boosters for the yellow fever vaccine last?
How long do boosters for the yellow fever vaccine last?
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What is a known long-term effect in survivors of Ebola infection?
What is a known long-term effect in survivors of Ebola infection?
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What is an important characteristic of post-vaccine immunity for yellow fever?
What is an important characteristic of post-vaccine immunity for yellow fever?
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Which cells do pathogens primarily infect and replicate within after entering a host?
Which cells do pathogens primarily infect and replicate within after entering a host?
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What are the initial symptoms of severe forms of viral infections mentioned?
What are the initial symptoms of severe forms of viral infections mentioned?
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Which factor does NOT significantly influence the severity of hemorrhagic fever (HF)?
Which factor does NOT significantly influence the severity of hemorrhagic fever (HF)?
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Which complication is associated with severe forms of viral infections?
Which complication is associated with severe forms of viral infections?
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How can laboratory confirmation of hemorrhagic fever (HF) be achieved?
How can laboratory confirmation of hemorrhagic fever (HF) be achieved?
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What is a common transmission route for hemorrhagic fever viruses?
What is a common transmission route for hemorrhagic fever viruses?
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Which long-term effect may survivors of severe hemorrhagic fever experience?
Which long-term effect may survivors of severe hemorrhagic fever experience?
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Which method is least effective for diagnosing hemorrhagic fever?
Which method is least effective for diagnosing hemorrhagic fever?
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What is often the cause of death in patients with hemorrhagic fever?
What is often the cause of death in patients with hemorrhagic fever?
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Study Notes
Haemorrhagic Fever (HF)
- Haemorrhagic fevers are viral infections with varying epidemiological characteristics.
- Common clinical manifestation is haemorrhagic syndrome, sometimes severe, but often absent.
- Aetiological agents are RNA genomic viruses, classified into four families: Flaviviridae, Bunyaviridae, Arenaviridae, Filoviridae.
Flaviviridae
- Yellow fever virus, dengue fever virus, Omsk virus, and Kyasanur forest disease virus are examples.
Bunyaviridae
- Nairovirus (Crimean-Congo HF), Phlebovirus (Rift Valley HF), and Hantaviruses (responsible for Hantavirus pulmonary syndrome or HF with renal syndrome) are included.
Arenaviridae
- Lassa fever virus, Junin virus (Argentinean HF), Machupo virus (Bolivian HF), and Guanarito virus (Venezuelan HF) are part of this family.
Filoviridae
- Ebola virus and Marburg virus are included.
Epidemiology
- Geographical distribution of HF varies.
- Many cases occur in warm, tropical, or subtropical climates.
- 'Imported' cases can be reported in travellers returning from tropical regions.
- Some regions have endemic HF, such as areas of Europe, the Balkans, Turkey, Russia.
- Climate change may increase cases by affecting animal reservoirs / vectors for HF viruses.
- Dengue fever widespread in Africa, America (North, Central, South), Southeast Asia, and western Pacific islands.
- Ebola HF and Marburg HF are mostly reported in Africa.
- Lassa fever is reported mainly in West Africa.
Reservoirs of Infection
- Rodents for Lassa and Hantaviruses.
- Bats and primates for Ebola and Marburg viruses.
- Humans for dengue fever.
- Transmission can be through direct contact with infected animals (rodent bites for Lassa and Hantaviruses, for example).
- Transmission can occur indirectly, including airborne transmission (inhalation of aerosolised urine/faeces particles).
Pathogenesis
- Pathogen enters the host (through skin or mucous membranes).
- Virus infects macrophages, and is transported to lymph nodes.
- Liver infection contributes to clotting factor shortage and aggravates haemorrhagic syndrome.
- Adrenal gland damage can affect blood pressure.
- Impaired immune response can reduce the control of viral infection.
- Macrophage infection generates mediators contributing to vascular endothelial disruption, vasoplegia, hypotension, and disseminated intravascular coagulation.
Clinical Picture
- Incubation period varies, from 3-7 days for most haemorrhagic fevers, to up to 21 days for Lassa and Marburg, and up to 2 months for Hantaviruses.
- Symptoms vary in severity.
- Some asymptomatic or mild forms present with fever and flu-like symptoms (myalgia, arthralgia, asthenia, pharyngeal pain, retro-orbital pain, sometimes nausea, vomiting).
- Severe forms can manifest with haemorrhagic syndrome (bruising, purpura, epistaxis, etc.), shock, and multiple organ failure.
Other Information
- Treatment is primarily supportive and symptomatic.
- Non-specific prophylactic measures are crucial (isolation of patients, PPE for medical personnel).
- Specific aetiologic therapy is limited.
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Description
This quiz explores haemorrhagic fevers, their viral origins, and associated families such as Flaviviridae and Filoviridae. Discover the clinical manifestations, epidemiology, and geographical distribution of these infections. Test your knowledge on significant viruses and their impact on health.
