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Lassa fever
From WikEM
Contents
Background
- RNA virus of arenaviridae family
- Endemic to parts of West Africa
- 100,000-300,000 infections every year
- Animal vector: Multimammate rat (Mastomys natalensis)
- A type of viral hemorrhagic fever
Transmission
- Infected Multimammate rats shed virus in urine and droppings
- Inhalation, ingestion, or direct contact of excrement or soiled food
- Direct contact with bodily fluids of infected human
Clinical Features
- Incubation period: 1-3 weeks
- 80% of infections are mild
- Undiagnosed or low fever, malaise, headache
- 20% of infections are severe
- vomiting, diarrhea, respiratory distress, facial swelling, body pain, hemorrhage, shock
- death within 2 weeks due to multi-system organ failure
- Occasional neurologic symptoms: hearing loss, tremors, encephalitis
Differential Diagnosis
Fever in traveler
- Normal causes of acute fever!
- Malaria
- Dengue
- Leptospirosis
- Typhoid fever
- Typhus
- Viral hemorrhagic fevers
- Chikungunya
- Yellow fever
- Rift Valley Fever
- Q fever
- Amebiasis
- Zika virus
Evaluation
- IgM or IgG ELISA or RT-PCR may be used to diagnose acute infections
- Lymphopenia and elevated transaminases are non-specific, but may indicate worse prognosis
Management
- Supportive care is the hallmark of management
- Strict isolation precautions: standard, contact and droplet
- Limit entry and maintain a log of people who enter the room
- Ribavirin has been shown to decrease mortality
- Most effective when given early (within 6 days)
Disposition
- Admit (consider ICU admission)
- Those that seek medical care are more likely to have serious infections:
- Hospital mortality rates can reach 25%
- Overal mortality rates are much less; around 5000 deaths per 100,000-300,000 infections annually
External Links
See Also
References
Authors
Colin Hoff, Michael Holtz, Ross Donaldson, Neil Young, Daniel Ostermayer, Claire
