Lassa fever is a viral infection carried by the multimammate rat (Mastomys natalensis), a common mice in equatorial Africa found across much of sub-Saharan Africa. The Lassa virus is transmitted to humans via contact with food or household items contaminated with rodent urine or faeces. Person-to-person infections and laboratory transmission can also occur, particularly in hospitals lacking adequate infection prevent and control measures.



In 80% of cases, the disease is asymptomatic, but in the remaining 20%, it takes a complicated course. Symptoms of the complicated cases include:

  • Hemorrhaging – in the gums, nose, eyes or elsewhere
  • Difficulty breathing
  • Cough
  • Swollen airways
  • Stomachache
  • Vomiting and diarrhea(both bloody)
  • Difficulty swallowing
  • Hepatitis
  • Swollen face
  • Pain in chest, back and abdomen
  • Shock
  • Hearing loss(sometimes permanent)
  • Abnormal heart rhythms
  • Hypertensionor
  • Pericarditis (a swelling of the sac that surrounds the heart).

Death can occur within 2 weeks after the onset of symptoms due to multiple organ failure. One of the most common complications of Lassa fever is deafness, occurring in around one third of cases; it varies in degree and can be permanent or total.

Preventive Measures for Lassa fever

  1. Prevention of Lassa fever relies on promoting good “community hygiene” to discourage rodents from entering homes. Effective measures include:
  • Storing grain and other foodstuffs in rodent-proof containers
  • Disposing of garbage far from the home,
  • Maintaining clean households and keeping cats. Because Mastomysare so abundant in endemic areas, it is not possible to completely eliminate them from the environment.
  • Family members should always be careful to avoid contact with blood and body fluids while caring for sick persons.
  1. In health-care settings, staff should always apply standard infection prevention and control precautions when caring for patients, regardless of their presumed diagnosis. These include:
  • Basic hand hygiene,
  • Respiratory hygiene,
  • Use of personal protective equipment (to block splashes or other contact with infected materials),
  • Safe injection practices and safe burial practices.
  • Health-care workers caring for patients with suspected or confirmed Lassa fever should apply extra infection control measures to prevent contact with the patient’s blood and body fluids and contaminated surfaces or materials such as clothing and bedding.
  • When in close contact (within 1 metre) of patients with Lassa fever, health-care workers should wear face protection (a face shield or a medical mask and goggles), a clean, non-sterile long-sleeved gown, and gloves (sterile gloves for some procedures).
  • Laboratory workers are also at risk. Samples taken from humans and animals for investigation of Lassa virus infection should be handled by trained staff and processed in suitably equipped laboratories under maximum biological containment conditions.
  • Health-care workers seeing a patient suspected to have Lassa fever should immediately contact local and national experts for advice and to arrange for laboratory testing.
  • Diagnosis of Lassa fever should be considered in febrile patients returning from West Africa, especially if they have had exposures in rural areas or hospitals in countries where Lassa fever is known to be endemic.
  1. Basic health education in Communities and its environs


Treatment of Lassa fever

  • Suspected patients with Lassa fever infection are admitted to isolation facilities where their body fluids and excreta are properly disposed.
  • The antiviral drug ribavirin if prescribed early is useful in fighting Lassa virus; however, its mechanism of action is still subject to debate.
  • While treating the disease, fluid levels, electrolyte balance, oxygenation andblood pressure in the patient is managed.



Complied by: eDokita Team



1. Tim Newman. Lassa fever: Diagnosis, Treatment and Prevention. Medical News Today. 2016

2. Ogbu O, Ajuluchukwu E, Uneke CJ (2007). “Lassa fever in West African sub-region: an overview”. Journal of vector borne diseases. 44 (1): 1–11. PMID 17378212

3. Public Health England. Lassa fever: origins, reservoirs, transmission and guidelines. 2016

4. WHO Fact Sheet. Lassa fever. 2016

5. Wikipedia. Lassa fever. 2016


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