Health Talk: Lassa Fever

Lassa fever or Lassa hemorrhagic fever (LHF) is an acute viral hemorrhagic fever caused by the Lassa virus and first described in 1969 in the town of Lassa, in Borno State, Nigeria.^[1] Lassa fever is a member of the arenaviridae virus family. Similar to Ebola,^[2] clinical cases of the disease had been known for over a decade but had not been connected with a viral pathogen. The infection is endemic in West African countries, resulting in 300,000–500,000 cases annually, causing approximately 5,000 deaths.^[3] Outbreaks of the disease have been observed in Nigeria, Liberia, Sierra Leone, Guinea, and the Central African Republic, but it is believed that human infections also exist in Democratic Republic of the Congo, Mali, and Senegal. The primary animal host of the Lassa virus is the Natal Multimammate Mouse (Mastomys natalensis), an animal indigenous to most of Sub-Saharan Africa.^[4] The virus is probably transmitted by contact with the feces or urine of animals accessing grain stores in residences. Given its high rate of incidence, Lassa fever has become a major problem in the African region

Symptoms

In 80% of cases, the disease is asymptomatic, but in the remaining 20%, it takes a complicated course. It is estimated that the virus is responsible for about 5,000 deaths annually. The fever accounts for up to one third of deaths in hospitals within the affected regions and 10 to 16% of total cases.
After an incubation period of six to twenty-one days, an acute illness with multiorgan involvement develops. Non-specific symptoms include fever, facial swelling, and muscle fatigue, as well as conjunctivitis and mucosal bleeding. The other symptoms arising from the affected organs are:

• Gastrointestinal tract
  • Nausea
  • Vomiting (bloody)
  • Diarrhea (bloody)
  • Stomach ache
  • Constipation
  • Dysphagia (difficulty swallowing)
  • Hepatitis
• Cardiovascular system
  • Pericarditis
  • Hypertension
  • Hypotension
  • Tachycardia (abnormally high heart rate)
• Respiratory tract
  • Cough
  • Chest pain
  • Dyspnoea
  • Pharyngitis
  • Pleuritis
• Nervous system
  • Encephalitis
  • Meningitis
  • Unilateral or bilateral hearing deficit
  • Seizures