Ten Things You Should Know About Lassa Fever (A Periodic Epidemic)

What Is Lassa Fever
According to World Health Organisation (WHO), Lassa fever is an acute viral haemorrhagic illness caused by Lassa virus, a member of the arenavirus family of viruses.

History Of Lassa Fever
Lassa fever was first reported in the 1950s. The virus was first described in 1969 as a result of the death of two missionary nurses in the town of Lassa, in Borno State, Nigeria. The virus is named after the town in Nigeria where the first cases occurred.
Lassa fever is relatively common in West Africa including the countries of Nigeria, Liberia, Sierra Leone, Guinea, and Ghana.

The Vector
Humans usually become infected with Lassa virus through exposure to food or household items contaminated with urine or feces of infected Mastomys rats.

Mastomys rats also known as multimammate rat. This is same rats we find around our environs. Mastomys rats breed frequently, and easily colonize human homes and areas where food is stored, these factors contribute to the relatively efficient spread of Lassa virus from infected rodents to humans.

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Transmission 
Transmission of Lassa virus to humans occurs most commonly through ingestion or inhalation.  The infected rodent shed the virus in urine and droppings and direct contact with these materials, through touching soiled objects, eating contaminated food, or exposure to open cuts or sores, can lead to infection.

Also of note its the airborne nature of lassa virus. Contact with the virus may also occur when a person inhales tiny particles in the air contaminated with infected rats excretions. This aerosol or airborne transmission may occur during cleaning activities, such as sweeping.

Person-to-person transmission may occur after exposure to virus in the blood, tissue, secretions, or excretions of a Lassa virus-infected individual.

Contact with body fluids and inhalation are the main causes of infection. Casual contact (including skin-to-skin contact without exchange of body fluids) does not spread Lassa virus.
Lassa virus may be spread in contaminated medical equipment, such as reused needles.

The Vaccine
Till date, no licensed vaccines are available to prevent Lassa virus (LASV) infection.

Preventing Infection
Setting up quarantine units in affected areas to isolate and treat patients who are infected and decreasing contact with mice.
Other efforts to control the spread of disease include having a cat to hunt vermin.
Creating contact tracing systems to find those who might have been exposed to the disease

Lassa Fever Epidemic 
This Epidemic has been reoccurring over time. Unfortunately about 15–20% of hospitalized people with Lassa fever will die from the illness. The fatality rate is estimated to be 1%, but during epidemics, mortality can climb as high as 50%.

The mortality rate is greater than 80% when it occurs in pregnant women during their third trimester. Pregnant mothers are usually adviced to induce or terminate the pregnancy so as to stand a chance of survival.

Sadly a prominent expert in the disease, Aniru Conteh, died from the disease.
Before now, the last epidemic occurred in Nigeria during 2018 and spread to 18 of the states. it was the largest outbreak of Lassa recorded.

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Synptoms
Diagnosis and prompt treatment are essential. Treatment is directed at addressing dehydration and improving symptoms. The incubation period of Lassa fever ranges from 6–21 days. The onset of the disease, when it is symptomatic, is usually gradual, starting with
fever, general weakness, malaise, headache, sore throat, muscle pain, chest pain, nausea, vomiting, diarrhoea, cough, abdominal pain.

In severe cases, facial swelling, fluid in the lung cavity, bleeding from the mouth, nose, vagina or gastrointestinal tract and low blood pressure may develop.

Shock, seizures, tremor, disorientation, and coma may be seen in the later stages. Deafness occurs in 25% of patients who survive the disease. Death usually occurs within 14 days of onset in fatal cases.

Treatment 
For treatment of Lassa fever, administering ribavirin which is an antiviral drug seems to be an effective if given early on in the course of clinical illness. Also Early supportive care with rehydration and symptomatic treatment improves survival.