Three Britons have been brought back to the UK from Sierra Leone for medical assessment after coming into close contact with two people who have been diagnosed with Lassa fever.One of the two Dutch nationals who contracted the virus - which has symptoms similar to Ebola - has since died.Public Health England confirmed that the three Britons have now been repatriated by the government and will be given treatment if required.The agency has got in touch with 15 other Britons who had contact with the Dutch Lassa fever cases to monitor them.Dr Jake Dunning, head of emerging infections and zoonoses at PHE, said: "It is important to emphasise that Lassa fever does not spread easily between people and the overall risk to the public is very low."There are no confirmed cases of Lassa fever in the UK."PHE is monitoring those who have had close contact with the foreign national to assess them as necessary and provide advice."PHE and the NHS have well established and robust infection control procedures for dealing with cases of imported infectious disease and these will be strictly followed."Symptoms of Lassa fever, for which there is no vaccine, start as a fever with aches and pains and can progress to headaches, vomiting and diarrhoea.The World Health Organisation says severe cases can cause victims to bleed from the mouth and nose.Lassa fever, like Ebola, can be spread through contact with the bodily fluids of sick people.It can also be contracted by humans through eating food that has been tainted by the urine or faeces of rodents.Most people with Lassa fever make a full recovery, although severe illness can occur.