A British soldier who recently returned from duty in west Africa has been diagnosed with the potentially fatal Lassa fever.

The man, who has not been named, is now in a stable condition at the high security infectious diseases unit at Coppetts Wood Hospital in north London.

He was working in the jungle in Sierra Leone when he became ill and was originally suspected of having malaria.

This is the sixth case of Lassa fever to have been imported to the UK since 1976.

The soldier was initially flown to Birmingham Heartlands Hospital, then transferred to London's Royal Free Hospital in Hampstead and finally to Coppetts Wood.

Lassa fever is caused by a virus that is found in west Africa and is excreted in rat urine.

The disease symptoms range from mild fever with a sore throat to chest pain and later bleeding.

In rural African villages it is spread either by contact with the rat urine directly or on food or clothes.

Lassa fever can be spread within hospitals by contact with infected blood and body fluids, but no such transmission has occurred in the UK.

There have been no cases in the UK of it being spread from patients to health workers or other people with whom they have come into contact.