Lassa fever, also known as Lassa hemorrhagic fever (LHF), is a type of viral hemorrhagic fever caused by the Lassa virus. Lassa fever is an animal-borne, or zoonotic, acute viral illness. It is endemic in parts of West Africa including Sierra Leone, Liberia, Guinea and Nigeria.

The illness was discovered in 1969 and is named after the town in Nigeria where the first cases occurred.

Lassa fever is a zoonotic disease, meaning that humans become infected from contact with infected animals. The animal reservoir, or host, of Lassa virus is a rodent of the genus Mastomys, commonly known as the “multimammate rat.” Mastomys rats infected with Lassa virus do not become ill, but they can shed the virus in their urine and faeces.

CAUSES OF LASSA FEVER
Once a Mastomys rat is infected with the virus, it can excrete the virus in its feces and urine, potentially for the rest of its life.
As a result, the virus can spread easily, especially as the rats breed rapidly and can inhabit human homes.

The most common method of transmission is by consuming or inhaling rat urine or feces. It can also be spread through cuts and open sores.
The rats live in and around human habitation, and they often come into contact with foodstuffs. Sometimes people eat the rats, and the disease can be spread during their preparation.

Person-to-person contact is possible via blood, tissue, secretions or excretions, but not through touch. Sharing needles may spread the virus, and there are some reports of sexual transmission.
Lassa fever can also be passed between patients and staff at poorly equipped hospitals where sterilization and protective clothing is not standard.

SYMPTOMS
Onset of symptoms is typically 7 to 21 days after exposure. In 80% of those who are infected little or no symptoms occur. These mild symptoms may include fever, tiredness, weakness, and headache. In 20% of people more severe symptoms such as bleeding gums, breathing problems, vomiting, chest pain, or dangerously low blood pressure may occur. Long term complications may include hearing loss. In those who are pregnant, miscarriage may occur in 95%.

Approximately 15%-20% of patients hospitalized for Lassa fever die from the illness. However, only 1% of all Lassa virus infections result in death. The death rates for women in the third trimester of pregnancy are particularly high. Spontaneous abortion is a serious complication of infection with an estimated 95% mortality in fetuses of infected pregnant mothers.

TRANSMISSION
Humans usually become infected with Lassa virus from exposure to urine or faeces of infected Mastomys rats. Lassa virus may also be spread between humans through direct contact with the blood, urine, faeces, or other bodily secretions of a person infected with Lassa fever.

There is no epidemiological evidence supporting airborne spread between humans. Person-to-person transmission occurs in both community and health-care settings, where the virus may be spread by contaminated medical equipment, such as re-used needles. Sexual transmission of Lassa virus has been reported.

PREVENTIONS
Prevention of Lassa fever relies on promoting good “community hygiene” to discourage rodents from entering homes. Effective measures include storing grain and other foodstuffs in rodent-proof containers, disposing of garbage far from the home, maintaining clean households and keeping cats. Because Mastomys are so abundant in endemic areas, it is not possible to completely eliminate them from the environment. Family members should always be careful to avoid contact with blood and body fluids while caring for sick persons.

TREATMENT
Health organizations hope that current work on vaccine development will be successful.
Rehydration and treatment of symptoms can improve the chances of survival if there is an early diagnosis.
Prescribed early, the antiviral drug ribavirin has proven useful in fighting Lassa virus, but how it works remains unclear.

However, access to ribavirin in the areas worst affected by the Lassa virus is limited.

Additionally, ribavirin may be toxic and teratogenic, meaning it can cause mutations. For this reason, it is not a perfect solution.
Ribavirin is not useful for preventing Lassa fever before it occurs, and there is currently no vaccine for this disease.

However, work on a vaccine is underway, and some drugs are showing promise.

Cases of Lassa fever have been discovered in Kebbi State with 1 death recorded and as such the corp members and general public should be careful.