Introduction.
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Lassa Fever is an acute viral illness that occurs in West Africa.
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It was first discovered in Lassa, Borno State Nigeria in 1969 when two missionary nurses died of the disease while in Nigeria.
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Infection linked to exposure to food contaminated by the animal vector for Lassa Fever- the multimammate rat “Mastomysnatalensis” very common in West Africa and Nigeria.
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The disease is endemic in some parts of Sierra Leone, Liberia, Guinea and Nigeria.
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One of hemorrhagic viral fevers – similar to Ebola.
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The incubation period is usually between 6 – 21 days, with the development of an acute illness as well as multi – organ involvement.
Risk of exposure.
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Those who live in or visit endemic regions- Sierra Leone, Guinea, Liberia and Nigeria other countries where exposure to the multimammate rat- Mastomys is high.
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Hospital staff.
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Close friends or family members of infected patients.
Transmission.
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The reservoir or host of Lassa virus is the rat known as the “multimammate rat” (Mastomysnatalensis).
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The rat is found commonly in the savanna and forests of West, Central and East Africa and commonly produces larges number of offspring and infected many households and areas where food is stored.
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Once infected, the rat excretes the virus in its urine and droppings.
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Infection is by ingestion of contaminated food, touching soiled objects or exposure of the rate’s urine and dropping to open wounds and cuts or inhalation.
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Direct transmission can also occur from eating the rat as done in some communities.
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Airborne transmission is via inhalation of tiny particles in the air contaminated with infected urine or droppings of the rat- may occur during cleaning activities such as sweeping.
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Person-to-person transmission can occur with direct exposure to blood, secretions, tissue and excretions of an infected individual.
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Skin-to-skin contact does not spread Lassa virus.
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Infection is common in healthcare settings from contaminated equipment and lack adequate protective equipment when nursing infected patients.
Signs &Symptoms
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Slight fever.
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General body weakness.
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Headache.
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Bleeding in the gums, eyes, and nose.
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Respiratory distress.
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Repeated vomiting.
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Facial swelling.
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Chest, back and abdominal pain.
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Shock.
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Hearing loss.
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Tremors.
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Encephalitis.
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Death may occur in 2 weeks due to multi-organ failure.
Management.
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Treatment is supportive with emphasis on nutrition, oral and intravenous rehydration.
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Strict barrier isolation- all body fluids contains infectious virions and should be handled with great care.
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Ribavirin, an antiviral drug has been used with success when given early.
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No vaccine is available yet.
Prevention.
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Avoid contact with the Mastomys rodents (rats).
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Putting away food in rodent-proof containers and keeping the home clean to discourage rats from entering the home.
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Avoid consumption of rats.
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Rodent fumigation and regular use of mouse traps/ gum can help reduce rat population around the home.
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Avoid contact with secretions (blood, excretions and other body fluids) of known patients.
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All caregivers to patients must take strict precautions and use specified protective clothing(face masks, goggles, gown, and proper sterilization).
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Barrier nursing and isolation of known patients.
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Educating people on high risk areas and reduction/control of rodent population.
say no to rats