Lassa’s fever is a severe animal borne, viral infection carried by a type of rat that is common in West Africa. Nigeria as the giant of Africa has the highest body count as a result of deaths related to this dreaded illness. Lassa’s fever which was first discovered in Nigeria in Bornu State in 1969 has an estimated incidence rate of 100,000 to 300,000 occurrences.

Infections of Lassa fever occur annually, with approximately 5,000 deaths. Just like any scientific statistic this number may be a wild estimation, and may not necessarily represent the current reality on ground. Yet, you should know better than to underestimate this terrifying  disease.

Lassa’s fever can be life-threatening, this dreaded disease has continued to be a pain in the neck in Nigeria with outbreaks occurring year in year out. Just this year, according to the latest figures from the Nigeria Center for Disease Control (NCDC), docketed Lassa fever Situation Report Epi Week 02: 06 – 12 January 2020, bestowing to this report, the number of new confirmed cases for the same period in 2019 was 60.

Lassa’s fever has killed 14 persons, infected 82 others in seven states and 13 local governments in the country. The states are Ondo, Taraba, Edo, Ebonyi, Plateau, Ogun and Bauchi.

The hemorrhagic virus was first discovered by Dr. Casals’s team, who was nearly killed by the virus.  According to a New York Times  publication in 2004 the virus was first found in the blood of three missionary nurses from the United States who had become ill in northern Nigeria.

Lassa’s fever virus being a hemorrhagic virus, implies that it can cause bleeding, according to an information published in 2018 by Tim Newman of Medical new today, ‘8 out of every 10 people with the virus have no symptoms’. Once this virus hits your vital organs for example the liver, kidneys, or spleen, it can be deadly.

From the history of Lassa fever, it shows that this terrifying fever can occur anytime in the year, even though more cases are recorded during the dry seasons which unvarying take place between November and May.

lassa fever

Hunting and consumption of rats or rats-products should be struck off your menu. Lassa’s fever is a member of the arena virus family of viruses. According to Wikipedia, ‘these viruses infect rodents and occasionally humans; arena viruses have also been discovered in snakes’.

Out of the known arena viruses, at least eight are known to cause human disease. Except from direct bites which is less likely, these viruses can be transmitted to humans from contacts with food or household items contaminated with rodent excreta. Proper food hygiene is recommended especially during outbreaks.


Yes! Just like its counterpart, Ebola virus and Marburg virus, Lassa fever is one of the hemorrhagic fever viruses. Contrary to the like of the Ebola Virus, Lassa fever isn’t that contagious or deadly. So you don’t actually need to move around with sterile gloves or avoid handshakes, Lassa virus is normally transmitted by the urine or feces of Mastomys (Mastomys is a type of rodent in the family Muridae peculiar to Africa) rats to people.

From human to human Lassa fever can be transmitted through direct contact with saliva, blood, bodily fluids, mucous membrane or sexual contact. You still need to be careful of this dreaded virus especially if you’re a medical laboratory scientist or your part of a hospital’s work force. You can become infected through improper infection-control precautions or if you’re an intravenous drug user, you can acquire it through reuse of disposable needles that has been used by an infected person.


No! But If you’re the type that consumes rat and other rodent as a staple food, you might need to control your appetite for bush meats. The main culprit in the Lassa fever virus case is the Mastomys rat, this rodent is common in West Africa, including countries like Benin, Guinea, Liberia, Nigeria, and Sierra Leone. 

According to research published by Am J Trop Med Hyg, ‘other rodents like Mastomys erythroleucus and Hylomyscus pamfi  have been recently recognized as carriers of the Lassa fever virus too, but their contribution to human infection is not known.

Typically, most Lassa fever cases occur in rural communities where rat populations are high, and the hygiene condition and sanitation conditions are generally poor. Since Lassa fever is mostly contracted through direct or indirect human exposure to fluids of the multimammate mouse, such as urine, saliva, and blood.


If you’re the type that thinks all fever is related to malaria, you might want to do a malaria test first to be sure of what you might be dealing with. The beginning of Lassa fever is usually gradual, do not try to self-medicate if you’re having symptoms.

It’s possible to assume you might be suffering from enteric fever, typhoid, malaria or any other common illness which shares similar symptoms. Usually, when your symptoms are not resolving, a smart thing to do is to consult your health care provider. Lassa’s fever might present with combine symptoms which may include but not limited to;

  • Abdominal pain.
  • General body weakness.
  • High grade fever.
  • Muscle pain.
  • Nausea
  • Chest pain.
  • Severe headache.
  • Sore throat.
  •  Un-explainable bleeding from orifices like; nose, anus, vagina, mouth etc.


Depending on the source of the sample, the virus could be cultured in 7 to 10 days. According to CDC, ‘this procedure should only be done in a high containment laboratory with good laboratory practices’. Lassa’s fever is most often diagnosed in the laboratory by using enzyme-linked immunosorbent serologic assays (ELISA); this detects IgM and IgG antibodies as well as a Lassa antigen. A process known as a reverse transcription-polymerase chain reaction (RT-PCR) can be used in the early stage of disease.

Diagnosis can also be made from formalin preserved bodies of Lassa fever victims by Immunohistochemistry.


The time-lapse between an infection and appearance of symptoms of the disease is usually 3 to 21 days. Early identification and treatment might increase your chances of survival.

However, it is possible to discover a case of Lassa fever late, probably because of certain factors like; paucity of diagnostic centers, nonspecific symptoms and knowledge deficit on the part of the clinicians. Bestowing to the aforementioned, your doctor may be tempted to administer antibiotics and anti-malaria to soothe your symptoms. Because of this, the likelihood of Lassa fever diagnosis may be prolonged by another 48 hours after you’ve reported in the clinic.

Early detection is the key to surviving a Lassa fever illness or outbreak, during the early stage of infection. Ribavirin also known as tribavirin, an antiviral medication used to treat other viral hemorrhagic fever, RSV infection, and hepatitis C, has been used with success in Lassa fever patients.

You may also be kept hydrated and your electrolytes balanced through administration of intravenous fluid. Other management may include, oxygenation and blood pressure monitoring, as well as treatment of any other complicating infections.


Survivors are likely to be inflicted with neurological problems which may include but not limited to hearing loss, tremors, and encephalitis.  Without prompt diagnosis and treatment death may occur within two weeks from the time your first symptom appeared. This is largely because of multi-organ failure.  According to CDC, ‘the most common complication of Lassa fever is deafness’


Currently, there is vaccine approved for use in humans as at 2019. But all hope is not lost as researchers in the US have been working hard on a promising vaccine since 2002. According to Wikipedia, they have developed a lookalike and competent vaccine against Lassa fever by way of recombining vesicular stomatitis virus vector which expresses a glycoprotein which is like the one found in Lassa fever.

Wikipedia went ahead to record that  After a single intramuscular injection, test primates survived deadly challenge and didn’t show any clinical symptoms at all.


Your first point of call when it comes to stopping the scourge of Lassa fever is to avoid deliberate hunting and consumption of rats and other rodent called bush meat. Try as much as possible to circumvent transmission of the Lassa virus from its host, especially, if you’re living in the geographic regions where there’s an outbreak.

Awesome tips for prevention of Lassa fever.

  • As a farmer provide proper silos for storage of harvested farm produce.
  • Avoid bush meats.
  • Avoid left over food- if you must leave any food overnight, store it in a better quality container with fitting lids.
  • Be vigilant and look out for Lassa fever signs and symptoms.
  • Do not dry your rice, garri, amala, apku etc on the floor or road sides while processing.
  • Do not litter your environment.
  • Hospital environment should be cleaned and disinfected regularly using the right things and techniques.
  • Keeping the home clean help to discourage rodents from entering homes.
  • Medical waste should be properly disposed or incinerated safely.
  • Properly discard and disinfect items used by Lassa fever patients.
  • Store foods such as grains, leguminous crops, garri etc away in rodent-proof containers.
  • Wash your bowls and utensils immediately after use under running water – especially during evening meals.
  • Standard precautions must be practiced at all times while handling infected patients and body fluids.


The national guidelines for Lassa fever case management and Infection prevention and control are available on the NCDC website for download (


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This Post Has 4 Comments

  1. ExoRank

    Awesome post! Keep up the great work! 🙂

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