What Is Lassa Fever? Symptoms And How It Spreads

British health authorities are investigating whether Lassa fever, a viral illness with symptoms similar to Ebola, may have spread to the UK. The UK Health Security Agency (UKHSA) confirmed that a person who travelled to England from Nigeria while infected with Lassa fever was diagnosed after returning to Nigeria. The UKHSA is now working to identify individuals who may have come into contact with the affected person during their stay in the UK.

Lassa fever is transmitted through direct contact with the blood, urine, or faeces of infected rodents, or from person to person through bodily fluids. Authorities are continuing to monitor the situation and take necessary precautions to prevent further spread. As UK authorities monitor for potential Lassa fever cases, it's important to understand the symptoms and how the virus spreads.

What Are the Symptoms of Lassa Fever and How Does It Spread?

How it spreads

According to the UK Health Security Agency, Lassa fever, the disease caused by the Lassa virus, was first described in the 1950s. The virus was identified in 1969 after 2 missionary nurses died from the disease in the Nigerian town of Lassa. Lassa fever is endemic (meaning it is regularly found) in parts of West Africa, particularly Guinea, Liberia, Nigeria and Sierra Leone. The Lassa virus is carried by a particular type of rodent, the Mastomys rodent, which occurs in high numbers in these countries.

The most common way for people to catch Lassa virus in these affected countries is through eating contaminated food or breathing in the virus. People can also be infected from the droppings of infected rodents, for example, on floors, home surfaces, or in food or water. Some people eat Mastomys, and they may catch Lassa virus when catching and preparing these rodents for eating.

Lassa virus does not spread easily between people. It can be spread from one person to another if they have contact with the body fluids of someone who has Lassa fever, such as blood, saliva, urine or semen.

Symptoms of Lassa fever

According to the UK Health Security Agency, most people who get Lassa fever have mild symptoms and make a full recovery. However, in some cases the virus can cause more severe illness and death.

• Mild symptoms of Lassa fever include:
• fever (high temperature) and shivering
• feeling tired and weak
• headache
• generalised pain
• sore throat
• More serious symptoms include:
• bleeding
• difficulty breathing
• vomiting
• facial swelling
• pain in the chest, back and stomach

Symptoms usually occur between 1 and 3 weeks after having contact with the Lassa virus.

Pregnant women are at higher risk of getting seriously ill if they catch Lassa fever, particularly in the third trimester. Catching the virus in pregnancy increases the chance of stillbirth and miscarriage, as well as serious complications and a higher chance of death for pregnant women.