VHF Flashcards
Front
Back
What are Viral Hemorrhagic Fevers (VHFs)?
Multi-system syndromes caused by enveloped ssRNA viruses, characterized by diffuse vascular damage and severe clinical events.
What are the key features of VHFs?
Enzootic diseases with incidental human cases, historic geographic localization, and potential use as bioterrorism weapons.
What are the four families of VHFs?
Filoviridae, Arenaviridae, Bunyaviridae, and Flaviviridae.
What are examples of Filoviridae viruses?
Ebola virus and Marburg virus.
What are examples of Arenaviridae viruses?
Lassa virus, Junin virus, Machupo virus, Guanarito virus, Sabia virus.
What are examples of Bunyaviridae viruses?
Hantavirus, Crimean-Congo Hemorrhagic Fever (CCHF) virus, Rift Valley Fever (RVF) virus.
What are examples of Flaviviridae viruses?
Yellow Fever virus, Dengue virus, Omsk Hemorrhagic Fever virus, Kyasanur Forest Disease virus.
What is the reservoir for Lassa virus?
Mastomys natalensis (Multimammate rat).
What is the primary mode of transmission for Lassa virus?
Contact with rodent urine, feces, or contaminated materials; person-to-person transmission through body fluids.
What is the incubation period for Arenaviridae infections?
7-21 days.
What are the clinical features of Lassa fever?
Gradual onset of fever and malaise, progressing to hemorrhage, leukopenia, thrombocytopenia, and neurological signs.
What are the outcomes of Lassa fever?
Case fatality of 20% in hospitalized patients, high mortality in pregnant women, and significant risk of hearing loss in survivors.
What is the treatment for Arenaviridae infections?
IV ribavirin within the first 6 days of symptoms; no vaccine available yet.
What are Filoviridae viruses associated with?
Severe hemorrhagic fevers like Ebola and Marburg, with case fatality rates of 30-90%.
What is the transmission route for Filoviridae viruses?
Close contact with body fluids, nosocomial spread, reuse of needles, and exposure to infectious tissues.
What are the clinical features of Ebola virus disease?
Abrupt onset of fever, chills, malaise, myalgia, and hemorrhagic symptoms; death often occurs 6-16 days after symptom onset.
What is the reservoir for Bunyaviridae viruses?
Various vectors: mosquitoes (RVF), ticks (CCHF), and rodents (Hantavirus).
What is the incubation period for Flaviviridae viruses like Yellow Fever?
3-6 days.
What are the complications of Dengue Hemorrhagic Fever?
Severe bleeding, shock, and worsened outcomes with serial infections of different serotypes.
What are the diagnostic methods for VHFs?
Viral culture, PCR, electron microscopy, and serology (limited for some VHFs).
What are the management strategies for VHFs?
Isolation, supportive care (fluid and electrolyte management, oxygen, blood pressure support), and avoiding antiplatelet drugs.
What are the prevention methods for VHFs?
Use of insect repellents, rodent control, avoiding contact with infected individuals, and vaccination where available (e.g., Yellow Fever).
What are the licensed vaccines for VHFs?
Vaccines for Yellow Fever, Kyasanur Forest Disease, and Ebola.
What is the potential for VHFs as biological weapons?
High due to severe morbidity and mortality, social and economic disruption, and difficulty in diagnosis and containment.
What are the infection control measures for VHFs?
Airborne and contact precautions, use of N-95 masks, double gloves, impermeable gowns, and negative pressure rooms.
What are the common differential diagnoses for VHFs?
Malaria, typhoid, viral hepatitis, measles, bacterial sepsis, and meningococcemia.
