Lassa Fever (Download PDF)

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An acute viral hemorrhagic illness. Also known as Lassa hemorrhagic fever (LHF) . Caused by Lassa virus which is a member of the arenavirus family of viruses. A single-stranded RNA virus. Endemic in Benin, Ghana, Guinea, Liberia, Mali, Sierra Leone, Togo and Nigeria including other West African countries.

Lassa Fever Outbreaks


  • Transmission occurs via contact with infected rodents (Mastomys natalensis) .
  • Consuming the animals or being exposed to their saliva or urine.

The hemorrhagic illness:

  • Person to person
  • Through bodily fluids

Mastomys Natalensis

  • The rodent reservoir of Lassa virus.
  • Chronic asymptomatic infection.
  • Mastomys rodents shed virus in their urine and droppings.
  • The rodents search for around food which has been poorly stored facilitating transmission.
  • The virus may spread through direct contacts through:
  • Touching contaminated objects
  • Eating contaminated food
  • Through contact with open sores
  • Found in close association with humans in rural villages and surrounding cultivated fields.
  • Rarely found in grasslands and at the forest edge.

It causes haemorrhagic fever with:

  • Sore throat
  • Oral ulcers
  • Nausea
  • Vomiting
  • Chest and abdominal pain


  • Fever
  • Gradual weakness
  • Malaise
  • Headache
  • Sore throat
  • Muscle pain
  • Chest pain
  • Nausea
  • Vomiting
  • Diarrhoea
  • Cough and abdominal pain
  • Bleeding

Spreads to Humans

  • Handling rats, food or household items contaminated with rats urine and faeces.
  • Direct contacts with a person infected with Lassa fever.
  • Contaminated clothing and bedding.


  • Lassa virus infections can only be diagnosed definitively in the laboratory using the following tests:
  • Reverse transcriptase polymerase chain reaction (RT-PCR) assay
  • Antibody enzyme-linked immunosorbent assay (ELISA)
  • Antigen detection tests
  • Virus isolation by cell culture


Personal Hygiene

  • Washing hands regularly with soap.
  • Use of personal protective equipment (to block splashes or other contact with infected materials) .

Food Hygiene

  • Food should be properly cooked.
  • Grains and other foodstuffs should be stored in rodent-proof containers.

Proper Sanitation

  • Keeping houses and environment clean.
  • Disposing of garbage far from the home.

Health-Care Settings

  • Staffs should always apply standard infection prevention and control precautions when caring for patients.

Here Precautions Include

  • Basic hand hygiene
  • Respiratory hygiene
  • Safe injection practices
  • Safe burial practices

- Published/Last Modified on: April 6, 2020

Health, Environment/Ecology, Down-to-Earth

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