Lassa Fever – Causes, Symptoms, Treatment

Lassa fever is one of the many viral haemorrhagic fevers like Rift Valley fever. It is endemic in west Africa but with air travel and the movement across borders, there is always a concern that there may be outbreaks in other parts of the world. The recent outbreak in Nigeria (2010) just before the Soccer World Cup tournament in South Africa has raised questions about it spread, but like most haemorrhagic fevers, infection is not as easily transmitted as the seasonal flu or even the swine flu.

Causes of Lassa Fever

The virus is spread by the Mastomys rodent, a type of rat, that is found in many parts of west Africa. The droppings (faeces) and urine contains the virus and if this contaminates food or is touched with bare hands and then allowed entry through the mouth, a person can become infected. Hygiene is therefore essential in preventing this disease.

It may be possible to acquire the infection through airborne particles of rat faeces and through human-to-human contact by coming into contact with the blood or secretions of the infected person. However, transmission through skin-to-skin contact is highly unlikely without the presence of body fluids.

Signs and Symptoms

Most cases of Lassa fever are asymptomatic and since it is an acute viral infection, an infected person may recover with little or no medical treatment.  However, as with any infection, HIV/AIDS patients are at risk, especially if their CD4 count is low.

The incubation period is 6 to 21 days meaning that you may only notice signs and symptoms of Lassa fever up to 3 weeks after coming into contact with the virus.

Some of the signs and symptoms may include :

• Fever.
• Sore throat.
• Cough.
• Chest pain or breastbone pain.
• Abdominal and/or back pain.
• Vomiting.
• Diarrhoea.
• Conjunctivitis (pink eye).
• Swelling of the face.

The signs and symptoms of Lassa fever infection is similar to other viral infections and the diagnosis may be missed. However, if the signs, symptoms and complications (below) arise, your doctor may have to have to conduct blood tests to confirm a diagnosis of Lassa fever.

• Bleeding from the mouth, nose or even eyes.
• Hearing loss (this can be permanent).
• Tremors.
• Encephalitis (brain swelling).
• Spontaneous abortion in pregnant women.
• Acute respiratory distress syndrome (seen as flaring of the nostrils, shortness of breath, paleness).

Treatment of Lassa Fever

Antivirals are the main treatment option for Lassa fever in conjunction with supportive treatment for the signs and symptoms present. In the early stages of the diseases, vomiting and diarrhoea can quickly lead to dehydration, further complicating the case. The focus should be on prevention, which includes proper hygiene and dealing with any rat infestation.