Brief History, Diagnosing, and symptoms of Lassa Fever

Brief History of 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. Lassa fever is a member of the Arenaviridae virus family. Similar to ebola, clinical cases of the disease had been known for over a decade but had not been connected with a viral pathogen.

Lassa fever is an acute viral illness that occurs in west Africa. The illness was discovered in 1969 when two missionary nurses died from it in Nigeria. The virus is name after the town in Nigeria that the illness first occurred. Lassa fever is endemic in parts of west Africa, to include the following areas:


  • Liberia
  • Guinea
  • Nigeria
  • Sierra Leone


The number of people who experience Lassa fever every year in west Africa is estimated to be between 100, 000 as well as 300, 000, with around 5, 000 people dying on the virus. The estimates are primitive because surveillance for cases on the disease is not conducted uniformly. In some aspects of Liberia and Sierra Leone, approximately 10-16% of these admitted to hospitals every year have Lassa fever, which indicates the serious impact on the virus on the population of such areas.

The main cause of Lassa virus is a rodent known as the Multimammate Rat of the genus Mastomys but it is not sure that which species of Mastomys are associated with Lassa fever. Mastomys rodents breed very frequently, produce large numbers of children, and are frequent in the savannas and forests of West, Central, and East Africa.

Mastomys that causes lassa fever
Mastomys that causes lassa fever

Signs and symptoms of Lassa Fever

Signs or symptoms of Lassa fever generally occur 1-3 weeks as soon as the patient comes into exposure to the virus. For many Lassa fever virus attacks (approximately 80%), symptoms are mild and are also undiagnosed. Mild symptoms include things like slight fever, general malaise as well as weakness, and headache.

In 20% of infected men and women, however, disease may progress to more severe symptoms including hemorrhaging (in gums, eyes, or nose, as examples), respiratory system distress, repeated vomiting, facial swelling, pain in the particular chest, back, and belly, and shock. Neurological problems have also been described, including hearing damage, tremors, and encephalitis. Death may occur within a couple weeks after symptom onset because of multi-organ failure.

The most typical complication of Lassa nausea is deafness. Various degrees of deafness occur in approximately one-third of infections, and perhaps hearing loss is permanent. As far as is famous, severity of the disease doesn’t affect this complication: deafness may develop in mild together with in severe cases.

Approximately 15%-20% of people hospitalized for Lassa fever die from the illness. However, only 1% of Lassa virus infections bring about death. The death rates for ladies in the third trimester connected with pregnancy are particularly high. Spontaneous abortion is a significant complication of infection with the estimated 95% mortality within fetuses of infected expectant mothers.

Because the signs and symptoms of Lassa fever are usually so varied and nonspecific, clinical diagnosis is frequently difficult. Lassa fever is usually associated with occasional epidemics, where the case-fatality rate can certainly reach 50% in hospitalized people.

Diagnosing Lassa Fever

Lassa fever is most often diagnosed using, ‘enzyme-linked immunosorbent serologic assays (ELISA), which detect IgM and IgG antibodies and also Lassa antigen. Reverse transcription-polymerase chain reaction (RT-PCR) can be utilized in diagnosing people that are in the early stage on the disease. The Lassa virus itself can be cultured in 7-10 days, yet the procedure ought to only be performed in a very high containment laboratory using good laboratory practices. Immunohistochemistry, conducted on formalin-fixed tissue individuals, might be used to manufacture a post-mortem diagnosis.

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