Uganda is reporting that an outbreak of the rare but deadly Marburg virus has killed one person and infected one more at a remote gold mine near the border with the Democratic Republic of Congo. Nick Wadhams has more from our East Africa bureau in Nairobi.

The man died on July 14 and blood tests conducted by the Atlanta-based Centers for Disease Control (CDC) confirmed that he had been infected with the Marburg virus.

Uganda's health ministry said a miner who was believed to have been infected first has survived. Because of the mine's remote location, deep within the Kakasi Forest Reserve, officials believe that the outbreak has not spread.  About 40 other miners and family members of the two infected people are being checked.

Marburg, which is closely related to the Ebola virus, is spread via bodily fluids such as blood and vomit, and there is no known cure.  The death rate is estimated at about 25 percent, and can occur with devastating speed, within two days.

Ugandan health ministry spokesman Dr. Sam Okware says doctors were concerned from the start about the man's symptoms. He says the government will wait until August 5, three weeks after the man died, to declare the outbreak over.

"The good thing about this particular variant is that you really need very close contact especially during burial," he noted.  "Fortunately the last patient who died, we were very suspicious and he was buried in a body bag and nobody touched the body. So we don't expect a lot of secondary contact."

The Marburg virus gets its name from the town in Germany where it was first reported, in 1967, and killed seven people. The virus was apparently carried by monkeys that had been brought to the town for blood tests as part of research on a polio vaccine.

The virus causes hemorrhagic fever and is notorious for its most ghastly symptom, severe bleeding from most bodily orifices. But that is actually quite rare and more common symptoms are fever and stomach pains.

A spokesman for the World Health Organization, Gregory Hartl, says the gold mine where the virus was contracted had been reopened only recently and was extremely dirty. He also says there is much about the deadly virus that is not understood.

"There have only been a little less than 400 cases and the outbreaks have been quite rare, so we really haven't had much chance to study the disease," he explained.  "There are ideas that it could either be bats or primates which houses the disease. We know that the area where these people contracted the disease there are apparently up to five million bats. This obviously could be a source of the disease."

The worst recent outbreak of Marburg occurred in 2005, when the virus swept through a children's ward in Angola and killed at least 200 people. Otherwise, it has largely been limited to the Democratic Republic of Congo and Uganda.