Lassa fever is an acute viral haemorrhagic illness caused by Lassa virus, a member of the arenavirus family of viruses. It is a deadly viral disease which claims hundreds of lives annually in west Africa. The threat of this rampant as it is transmitted to humans through contact with rodents of the genus and Mastomys which carry the Lassa virus.
Humans usually become infected with Lassa virus through exposure to food or household items contaminated with urine or faeces of infected Mastomys rats. The disease is endemic in the rodent population in parts of West Africa.
Lassa fever is known to be endemic in west Africa countries like Benin, Ghana, Guinea, Liberia, Mali, Sierra Leone, Togo and Nigeria, but probably exists in other West African countries as well with the outbreaks occurring during the dry season.
According to the World Health Organization About 80% of people who become infected with Lassa virus have no symptoms. 1 in 5 infections result in severe disease, where the virus affects several organs such as the liver, spleen and kidneys.
The virus could be caused by several means, it is often called Zoonotic disease as lassa fever is transmitted from animals to humans. Rodent reservoir which is the multimammate rat, a rodent commonly found in the west Africa can be transmitted through direct contact with human as they can be infected through Ingesting food or household items contaminated with rodent urine or feces, Inhaling dust particles contaminated with rodent urine or feces.
Human to human transmission/spread between humans could be through direct contact with the blood, urine, feces, or other bodily fluids of an infected person, healthcare settings with unsafe injection practices, such as reusing needles, can also facilitate transmission of the deadly disease.
Study reveals that the virus endemic to West Africa, has found that it infects 2.7 million people a year, ten times more than health agencies had assumed.
As of February 23, 2025, Nigeria has reported 2,492 suspected Lassa fever cases, with 506 confirmed and 6 deaths, with Bauchi, Edo, and Ondo states reporting the majority of cases.The overall case fatality rate is 1% but observed case fatality rate among patients hospitalized with severe diseases of Lassa fever is 15% and above.
The Symptoms of Lassa fever can range from mild to severe, with the incubation period being 2 to 21 days after infection. Mild symptoms include fever, fatigue, headache, and sore throat, while severe cases can involve bleeding, difficulty breathing, and facial swelling, respiratory distress, hemorrhaging, and even death.
To add to, the disease was first recognized in Nigeria in 1969 as Humans contract Lassa virus (LASV) primarily through contact with contaminated excreta of the rodent Mastomys natalensis, which is the natural reservoir. As of March 2, 2025, Nigeria has recorded 535 confirmed cases and 98 deaths from a total of 2,728 suspected cases across 14 states, Ondo, Bauchi, Edo, Taraba, and Ebonyi account for 91% of all reported cases, with ten local government areas—Owo, Akure South, and Akoko South-West among them—contributing to 68% of the outbreak
Recently a report has it that a case happened in Ogun State where a 25-year-old female NYSC member who fell ill in Ondo State was brought to a secondary health facility in Ijebu North LGA but was later reported dead.
Moreover, inadequate health and surveillance systems,Genetic diversity of the virus,Inadequate health infrastructure, socio-economic factors such as poverty and lack of access to healthcare perpetuate the disease and hinder /Limits disease surveillance and response.
Diagnosis and prompt treatment are essential. The overall case-fatality rate is 1%. Among patients who are hospitalized with severe clinical presentation of Lassa fever, case-fatality is estimated at around 15%. Early supportive care with rehydration and symptomatic treatment improves survival. The lack of a licensed vaccine and effective treatment exacerbates the disease’s impact.
However, to combat Lassa fever, a multi-faceted approach should be emulated like; Collaborative research for medical countermeasures and tailored public health policies, Addressing the interconnection between animals, humans, and ecosystems, Enhancing disease surveillance, diagnosis, and treatment, people of all age groups who come into contact with the urine, faeces, saliva, or blood of infected rats, as well as those living in rat-infested environments, are at risk of contracting Lassa fever.
Agency should create awareness on keeping the environment rodent-free and cleaning ones homes, markets and surroundings regularly to eliminate conditions that encourage rat infestation or reduce breeding grounds for rats. Also, process or prepare rats (bushmeat) properly before consumption, store food items such as rice, garri, beans, and maize in tightly sealed containers to prevent contamination, avoid open drying of foodstuff outside or on roadsides, and cover your dustbins and properly dispose of refuse or waste to limit rodent access.
Proper hygiene by washing your hands frequently with soap and running water should be maintained, especially after handling food or waste or using hand sanitizers when necessary, eliminating rats in homes and communities by setting rat traps and other appropriate and safe means.
Additionally, bush burning and deforestation should be as these can destroy the homes and food sources of rodents, driving them to migrate from the bushes to human residences to find food.
