Lassa viral haemorrhagic fever occurs in West Africa and is an acute illness that can last anywhere from 1 to 4 weeks. The disease has been known since the 50’s but was not identified until 1969. The virus that causes Lassa fever is a single-stranded RNA virus.

Other areas have been known to have active cases of the disease including Guinea, Liberia, Sierra Leone and certain parts of Nigeria. There may be cases not reported in other West African countries.

Symptoms of Lassa Fever

Most of the cases of Lassa fever go asymptomatic with the about 20% having severe multi-system symptoms including involvement of the spleen, and kidneys. Incubation period for Lassa fever is from 6 to 21 days. The disease if symptoms are to show will start out gradual with a fever and general weakness and malaise.

A few days later a headache, sore throat, muscle pain, chest pain, nausea, vomiting, diarrhea, cough and abdominal pain will occur. If the case is severe facial swelling, and fluid in the lungs may occur followed by bleeding from the mouth, nose, vagina or gastrointestinal tract and low blood pressure. Lab tests will show protein in the urine.

Severe cases will note shock, seizures, tremors, disorientation and coma in the last stages of the disease. 25% of patients experience deafness, which may be recovered after 1 to 3 months following recuperation from the disease. While the patient is recovering they may notice hair loss or gait disturbance.

Records indicate that there has been as many as 5000 deaths contributed to Lassa fever. The sad news is that the disease severely affects pregnant women in the last trimester with both maternal and fetal death in 80% of the cases.

The tropical disease Lassa occurs in people of all ages, male and female with those living in rural areas at greatest risk especially in areas where there is poor sanitation and/or crowded living conditions.

Barrier nursing procedures and other infection control procedures must be followed or healthcare workers will be at risk for infection.

Lassa fever can be passed from human to human from contact with infected blood, urine or feces and also by touching other bodily secretions of a person who has Lassa fever. If medical equipment is contaminated such as needles that are reused then it can be transmitted that way too. There have also been reported cases of sexual transmission of Lassa fever.


It is difficult to diagnose Lassa fever because the symptoms are varied and some are non-specific especially in the early stages of the disease. There are many diseases with the same symptoms such as malaria, typhoid fever, yellow fever and other viral haemorrhagic fevers.

To make an exact diagnosis testing must be done in specialized laboratories and specimens must be handled with extreme care so as not to infect lab workers. There are Lassa antigen, and anti-Lassa antibodies that can be identified in a laboratory setting to make the diagnosis.


Ribavirin, a antiviral drug is used to treat Lassa fever if it is caught in the early stages.

Prevention Measures:

The best way to prevent Lassa fever is to practise good community hygiene, which will discourage rodents from entering homes. Foodstuffs and grains need to be stored in rodent-proof containers and garbage should be disposed of away from homes. The presence of cats and keeping homes clean are two more good preventatives.

Good protective techniques should be used when treating any patient that is suspected of having Lassa fever to help prevent the spread of the disease. This includes wearing protective clothing such as face shields, gloves, gowns and masks. All contaminated equipment must be sterilized before using again.

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