Introduction

Lassa fever (LF) is a viral disease that causes hemorrhagic fever, a life threatening illness that affect the clotting ability of blood and it is frequently shown by immunosuppression. It is zoonotic disease (that is transmitted from animal to humans). The causative agent is Lassa virus (LV). Lassa virus (LV) is an enveloped, single stranded RNA virus in the family of Arenaviridae.

The virus was discovered in 1969 in Nigeria in a village called Lassa in Borno State. It first manifested by a missionary nurse Laura wine, after attending to an obstetrical patient in Lassa village. Two other people were killed by the virus (the missionary nurse that cared for the index case and a technician from the lab that the virus was isolated). Jordi Casals and his team isolated the Lassa virus for the first time at University of Yale. Since then, the virus has been an endemic disease in parts of West African countries including Nigeria. Nigeria had the highest outbreak in the year 2018.

Transmission

Lassa virus is transmitted from “Multimammate rat ” (Mastomys natalensis) to humans. The vector shed the virus via urine and faeces. The humans becomes infected by direct contact with the shed urine and faeces of the rodent via consuming foods, contact with infected surfaces and contact with open cut wounds. Human to human transmission is possible via contact with blood or body fluids of an infected person. The incubation period is 1-3 weeks after exposure to the virus. Lassa virus gains entry into the host cell by receptor-mediated endocytocis.

Prognosis is good when treatment is commenced early.

Diagnosis

Diagnosis is by using enzyme-linked immunosorbent serology assay (ELISA).

Signs/Symptoms

The onset of the disease may mimic Malaria fever, making it difficult to identify. It affects most of the body tissues. Its signs/symptoms may include the following :

* Fever

* Headache

* Malaise

* Cough

* Sore throat

* Body weakness/pains

* Gastrointestinal tract manifestations e. g. diarrhea, bloody stool.

* Tinnitus (ringing in the year)

* Mucosal bleeding

Management/Treatment

There is no vaccine yet but ribavirin has been successful in the treatment of Lassa Fever.

Other Management includes:

* Oxygenation therapy

* Fluid and electrolytes therapy and

* Blood pressure monitoring

Complications

* Hearing loss

* Hemolytic anaemia

* Spontaneous abortion can occur in infected pregnant woman

* Bleeding disorders e.g. Disseminated intravascular coagulation (DIC).

Prevention

* Early detection and treatment.

* Public sensitization/Education, this creates awareness of the existence of the disease thereby alerting the public to be vigilant and take immediate precautions to prevent the disease.

* Good community/home hygiene to prevent the breeding and invading of the rodent into our communities and homes respectively.

* Proper storage of food to prevent food being contaminated with the urine and faeces of the rodent.

* Maintaining universal precautions e.g hand washing, use of personal protective equipments (PPE) by people caring for infected patients.

* Observing infection control measures in the hospital settings, this results in proper handling of harmful and infected wastes and proper disposal of fluids and wastes from infected persons.