Lassa fever: A comprehensive review of virology, clinical management, and global health implications

Table 1 Clinical manifestations of Lassa fever

Stage	Duration	Symptoms	Description
Incubation period	Days 2-21	Typical asymptomatic	Virus is replicating; no external signs
Early stage	Days 1-6	Fever, sore throat, muscle aches, chest pain, vomiting, diarrhea	Resembles malaria or typhoid; diagnostic confusion common
Progression to severe	Days 7-14	Facial swelling, mucosal bleeding, pleural/pericardial effusion, hypotension, respiratory distress	Indicates systemic involvement and vascular leakage
Neurological phase	Advanced (≥ day 10)	Confusion, seizures, encephalopathy	May progress to multiorgan failure
Complications	Variable	Hearing loss (up to 30% of survivors), myocarditis, chronic fatigue, spontaneous abortion (pregnancy)	Hearing loss may be permanent; pregnant females are at very high risk
Case fatality risk	Severe cases	15%-20% in hospitalized patients	Higher in late-presenting cases and pregnant females
Recovery phase	After 2-3 weeks	Weakness, fatigue, dizziness, depression	Long recovery; some may need audiological or psychological follow-up