Marburg Fever a Global Threat, Bats May Play a Role

GENEVA, Switzerland, August 21, 2007 (ENS) - Marburg hemorrhagic fever is a global threat to public health, the World Health Organization says in a new report on the disease.

"Emerging viral diseases such as ebola, marburg hemorrhagic fever and nipah virus pose threats to global public health security and also require containment at their source due to their acute nature and resulting illness and mortality," says a summarized version of the 2007 World Health report due to be released in Geneva tomorrow.

Marburg hemorrhagic fever is a severe and highly fatal disease caused by a virus from the same family as the one that causes Ebola hemorrhagic fever. Both diseases are rare, but can cause dramatic outbreaks with high fatality. These viruses are among the most virulent pathogens known to infect humans. There is currently no specific treatment or vaccine, according to the World Health Organization.

Two cases of Marburg virus infection have recently been reported in Uganda. One of the people, a miner, died in July.

Results of laboratory tests on blood samples from Kampala and Kamwenge performed by the U.S. Centers for Disease Control and Prevention, CDC, have confirmed Marburg virus infection in the mine worker, and in one of his close contacts during his illness.

Contact tracing and monitoring has been carried out to ensure no further transmission of disease, and the extended contacts are coming to the end of their period of observation.

An international team of scientists is working to identify the hosts of the virus and mode of its natural transmission in the environment. They are focusing on bats living in mines near where the miner became ill.

Bats emerge from a mine in the Kitomi Forest Reserve. (Photo by Pierre Formenty courtesy WHO)
On Friday, experts from the CDC, the National Institute of Communicable Diseases in South Africa and the World Health Organization entered a lead and gold mine in a remote forest reserve in western Uganda to search for bats, which are suspected to be the source of the latest Marburg outbreak.

About five million bats live in and around the small mine, which is situated in Kitaka, about 300 km (200 miles) from Uganda's capital Kampala.

Located inside the Kitomi Forest Reserve, the mine is surrounded by hills and banana plantations. The nearest community is five kilometers (three miles) away and there is a miners' camp nearby.

The mine had operated, sometimes illegally, from the 1930s to the 1980s when it was abandoned. Since it legally reopened last January, between 50 and 90 miners dig there for lead and gold ore.

Wearing protective gear, members of the ecological team set up mist and harp nets every night to catch bats as they leave the mine to hunt for food and water. They catch about 100 bats every night and aim to net more than 1,000.

In a scientific lab set up near the mine, researchers look for signs of Marburg virus in captured bats. (Photo by Chris Black courtesy WHO)
The captured bats are taken to a nearby laboratory, established for Marburg research, where scientists there work through the night, taking blood and organ samples to look for Marburg virus antibodies.

The blood and organ samples are preserved in liquid nitrogen and carried to Kampala. They will then be transported to laboratories of CDC in Atlanta, Georgia, and of NICD in South Africa for further analysis.

Illness caused by Marburg virus begins abruptly, with severe headache and severe malaise. Many patients develop severe hemorrhagic manifestations between days five and seven, and fatal cases usually have some form of bleeding, often from multiple sites.

Fatality rates have varied, from 25 percent in the initial laboratory-associated outbreak in 1967, to more than 80 percent in the Democratic Republic of Congo from 1998-2000, to even higher in the outbreak that began in Angola in late 2004.

There is no precise evidence indicating how Marburg virus is transmitted to humans, but the World Health Organization says bats are suspected to play a role.

Copyright Environment News Service (ENS) 2007. All rights reserved.