GENEVA, Aug 3 (Reuters) - Ugandan health officials have collected blood samples from dozens of people who may have been exposed to Marburg haemorrhagic fever and others were being monitored, the World Health Organisation (WHO) said on Friday.

The rare but highly fatal disease killed a 29-year-old gold miner in Uganda's western Kamwenge district in mid-July.

A 21-year-old who accompanied the victim to the hospital fell ill, but has since recovered. Tests have not yet confirmed whether he had caught the fever which is caused by a virus from the same family as the one causing Ebola and can lead to bleeding from multiple orifices.

Three other cases of mine workers who took ill in mid-June were also being investigated as a "matter of priority", the United Nations health agency said in a statement.

"Case investigations, including extensive contact tracing and contact monitoring are underway at the mine, at the health care facilities that cared for the men during their illness and within the community," it said.

WHO said a national task force enjoying strong political support has set up quarantines and put in place infection control measures to monitor future cases and to encourage safe burial practices among the population.

Gregory Hartl, a WHO spokesman, said relatives of the survivor, who is now in Kampala, were being checked in the capital and Wakiso and Kayunga districts as a precaution.

Ugandan health officials were also going to Luwero district where the dead gold miner was buried to see if any relatives had had contact with the body.

Close contact with a severely ill patient and certain burial practices are common routes of infection for the disease, which spreads through blood or other body fluid.

There is no vaccine or specific treatment for the fever which begins with a headache followed by severe debilitation.

Officials will have to wait two incubation periods, or a total of 20 days, before determining whether the virus has been contained, Hartl said.

Despite years of research, no animal reservoir or other environmental source of the virus has been identified although bats and monkeys have been investigated.

A major outbreak occurred among gold miners in the Democratic Republic of Congo between 1998 and 2000, causing 128 deaths among 154 infections. An outbreak in Angola in 2004-05 killed 150 out of 163 cases.

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