Lassa Fever: Transmission from Multimammate Rats, Clinical Spectrum, Ribavirin Treatment, and Endemic Regions

Lassa fever is an acute viral hemorrhagic illness caused by Lassa virus (Arenaviridae, single‑stranded RNA). Endemic in West Africa.

Transmission

• Primary reservoir: Mastomys natalensis (multimammate rat) – chronic asymptomatic shedding in urine/feces.
• Human exposure: Aerosolized excreta, contaminated food/household items, direct contact.
• Person‑to‑person: Body fluids (blood, secretions) – nosocomial outbreaks common without IPC.
• Sexual transmission reported (virus in semen months post‑recovery).

Clinical Spectrum

• Mild (80%): Low‑grade fever, malaise, headache, myalgia – often undiagnosed.
• Severe (20%): High fever, pharyngitis, retrosternal pain, vomiting, facial edema, bleeding (mucosal, GI), pleural effusion, encephalopathy, shock, multi‑organ failure.
• Pregnancy: High mortality (3rd trimester); fetal loss >80%.

Diagnosis

• RT‑PCR (blood, serum) – gold standard.
• IgM/IgG ELISA (later).
• Viral culture (BSL‑4 only).

Treatment

• Ribavirin IV – most effective if started ≤6 days of symptoms.
• Supportive: fluid/electrolyte management, blood products, renal replacement.

Prevention

• Rodent control, food storage, hygiene.
• Strict IPC in healthcare (VHF precautions).
• No licensed vaccine; candidates in development.

Lassa fever remains a neglected tropical disease with epidemic potential.