After close dealings with two people infected with Lassa fever, three British nationals were repatriated from Sierra Leone to the UK for medical examination.

The two infected persons were both Dutch nationals working in Sierra Leone, one of whom has died from the virus.

Public Health England have informed that 15 British nationals may also be at risk. Health officials say the move is a precautionary measure.

However, there is a very low risk to the broader population. Lassa fever has not been reported in the UK. Public Health England says the situation is being closely watched.

Unlike Ebola, Lassa fever can be transmitted by contact with infected people’s body fluids (blood, saliva, urine, or semen).

It is also possible for humans to get it through contact with the urine or faeces of contaminated animals carrying the disease.

The illness usually causes signs of fever and flu. Most people are going to completely recover, but the disease can be deadly.

Described as Ebola’s cousin, Lassa fever is prevalent in eastern Sierra Leone, but there have been cases reported over the past five years in northern and southern parts of the country.

It is also prevalent in Liberia, Guinea and several other West African countries. There is presently no vaccine that can be used to prevent it, but antiviral drugs can help in its treatment. The doctor who passed on, developed signs of Lassa fever after conducting a Caesarean section.

According to Dr. Jake Dunning, from Public Health England, “It’s important to emphasize that Lassa fever doesn’t spread easily among people, and the potential risk to the public is very small,”.

“PHE and NHS have well-established and robust infection control procedures for dealing with cases of imported infectious disease and these will be followed strictly,” he said. Imported occurrences of Lassa fever in the UK are very uncommon.

Since 1980, just a handful of confirmed cases have been imported and without evidence of further transmission.