Lassa fever

Lassa fever is an acute viral hemorrhagic fever caused by the Lassa virus, a member of the Arenaviridae family. It is endemic in several West African countries and poses a significant public health threat due to its potential for severe illness and human-to-human transmission.

Understanding Lassa Fever:

  • Causative Agent:
    • The Lassa virus.
  • Reservoir Host:
    • Multimammate rat (Mastomys natalensis).
  • Transmission:
    • Primarily through contact with the urine or feces of infected Mastomys rats.
    • Consumption of food or water contaminated with rat excreta.
    • Inhalation of aerosolized rat excreta.
    • Human-to-human transmission through contact with infected blood, bodily fluids, or secretions.
    • Nosocomial transmission (hospital-acquired) due to inadequate infection control measures.

Transmission Details:

  • Rodent-to-Human Transmission:
    • Mastomys rats are common in households and farms, increasing the risk of human exposure.
    • People living in rural areas or with poor sanitation are at higher risk.
  • Human-to-Human Transmission:
    • Occurs through direct contact with infected bodily fluids.
    • Healthcare workers are at significant risk if they do not adhere to strict infection control protocols.
    • Family members caring for infected individuals are also at risk.

Symptoms:

Lassa fever presents a wide range of symptoms, from mild to severe:

  • Initial Symptoms (Mild Cases):
    • Fever.
    • Fatigue.
    • Weakness.
    • Headache.
    • Sore throat.
    • Muscle aches.
  • Severe Symptoms:
    • Hemorrhagic manifestations (bleeding from gums, nose, eyes, or into the gastrointestinal tract).
    • Respiratory distress.
    • Chest pain.
    • Facial swelling.
    • Repeated vomiting.
    • Shock.
    • Neurological problems (encephalitis, seizures).
    • Deafness (a common complication).
  • Complications:
    • Deafness (most common long term complication)
    • Hemorrhage.
    • Multi-organ failure.
    • Death.

Diagnosis:

  • Laboratory testing is essential for confirming Lassa fever:
    • RT-PCR (reverse transcription-polymerase chain reaction) to detect the virus’s RNA.
    • Antibody detection tests (ELISA).
    • Virus isolation.

Treatment:

  • Ribavirin, an antiviral drug, is effective when administered early in the course of the illness.
  • Supportive care is crucial:
    • Fluid and electrolyte management.
    • Blood transfusions.
    • Treatment of complications.

Prevention:

  • Rodent Control:
    • Improving sanitation and hygiene to reduce rodent populations.
    • Storing food in rodent-proof containers.
    • Trapping and eliminating rodents.
  • Safe Food Handling:
    • Thoroughly cooking food.
    • Avoiding consumption of food contaminated with rodent excreta.
  • Infection Control:
    • Strict adherence to infection control measures in healthcare settings.
    • Proper use of personal protective equipment (PPE).
    • Safe burial practices.
  • Public Education:
    • Raising awareness about the risks of Lassa fever and preventive measures.

Public Health Importance:

  • Lassa fever outbreaks can have significant public health consequences.
  • The potential for human-to-human transmission poses a risk of widespread outbreaks.
  • The disease is a major concern in endemic regions of West Africa.
  • The high rates of deafness amongst survivors is a very concerning long term effect.

It’s vital for healthcare professionals and the public to be aware of Lassa fever and take appropriate precautions.