Last reviewed May 16, 2026

Lassa fever vs malaria: why fever should not be guessed

In Nigeria, malaria is common, but not every fever is malaria. Lassa fever can start with symptoms that look like other febrile illnesses.

Quick answer

Lassa fever and malaria are different illnesses with different causes and treatments. Because symptoms can overlap early, a person with persistent or severe fever should seek medical evaluation instead of guessing.

Lassa fever

Caused by Lassa virus. Linked to infected rodents and, in some settings, contact with blood or body fluids of infected people.

Malaria

Caused by Plasmodium parasites transmitted by infected mosquitoes. WHO emphasizes early diagnosis and treatment to prevent severe disease.

Symptoms can overlap

Fever, weakness, headache, vomiting, diarrhoea, body pain, and fatigue can occur in multiple infections. Lassa fever may also develop sore throat, chest pain, bleeding, low blood pressure, or severe complications.

When to seek care urgently

  • Fever that is severe, persistent, or worsening.
  • Bleeding, confusion, fainting, severe weakness, or breathing difficulty.
  • Fever after rodent exposure or contact with a suspected Lassa fever case.
  • Pregnancy with fever or possible exposure.

Related: Lassa fever explained, Rat urine disease, Rat exposure steps.

Official sources

WHO Lassa fever, WHO malaria, and NCDC Lassa fever.