An outbreak of the deadly Ebola virus has killed 13 people in Uganda.

The World Health Organisation has said that efforts are under way to contain the hemorrhagic fever.

There is no treatment and no vaccine against Ebola, which is transmitted by close personal contact.

Depending on the strain, it can kill up to 90% of those who contract the virus.

WHO's representative in Uganda Joaquim Saweka said suspected Ebola infections emerged in early July in Kibale district, about 170km west of the capital, Kampala.

Mr Saweka said there are a total of 20 people suspected to have contracted Ebola and 13 of them have died.

He said the origin of the outbreak had not yet been confirmed, but 18 of the 20 cases are understood to be linked to one family.

Kibale is near the Democratic Republic of Congo (DRC) where the virus emerged in 1976, taking its name from the Ebola River.

The symptoms include sudden onset of fever, intense weakness, muscle pain, headache and sore throat, followed by vomiting, diarrhoea, rashes, impaired kidney and liver function and both internal and external bleeding.

Ebola was last reported in Uganda in May last year when it killed a 12-year-old girl.

The country's most devastating outbreak was in 2000 when 425 people were infected, more than half of whom died.