New virus causes South American fever

WASHINGTON (Reuters) - Scientists have identified a new virus that causes bleeding and shock and killed at least one man in a remote area of Bolivia.

It appears to be highly deadly and, like other related viruses, is carried by rodents, the researchers report in Friday's issue of the Public Library of Science journal PLoS Pathogens.

They have named the new virus the Chapare arenavirus, and say it is related to the viruses that cause Lassa fever and other rare viruses such as Junin, Machupo, Guanarito, and Sabia viruses. They have about a 30 percent fatality rate.

But it is genetically distinct.

"It is quite a unique virus and we are suggesting that it be considered as a new species of arenavirus," Stuart Nichol of the U.S. Centers for Disease Control and Prevention, who helped study the virus, said in a telephone interview.

The 22-year-old man was one of several who died of hemorrhagic fever near Cochabamba, Bolivia. A team of Bolivian health authorities and U.S. Navy health experts from Lima, Peru, got the samples.

Nichol said the virus has almost certainly been around for some time. "This is not something that suddenly mutated into this new virus," Nichol said. "This one is newly discovered."

Doctors at first thought the patient had dengue fever or yellow fever -- caused by two unrelated viruses that can also cause hemorrhagic fevers.

"He went on in a few short days from a kind of fairly flu-like illness with headache, fever and muscle aches and deteriorated rapidly into ... the shock and bleeding," Nichol said.

Usually the bleeding is not dramatic at first -- marked by so-called petechia or the breaking of small blood vessels in the skin and eyes. "You'll start seeing bleeding from the nose and mouth and gums," said Nichol.

But it is never so severe as fictional accounts and films about viruses, Nichol stressed.

The new virus is likely carried by a rodent, as most are, and does not pose a widespread threat.

Nichols said he wanted to alert clinicians in the affected area to make sure they are on the lookout. "We are probably missing a lot of these sorts of infections that are going on in these communities," he said.

It has not been easy trying to find out more about the virus. "There was a team that went out to the local area where this person had been affected," he said.

They sampled several rodents but could not find any infected with the virus.

"There's a lot of political problems. This is one of the major coca growing areas of Bolivia," added Nichol.

South American countries have been battling outbreaks of several viruses, including mosquito-borne dengue and yellow fevers. Dengue has killed at least 87 people in the region and sickened more than 93,000 this year, and at least 17 people have died of yellow fever in Brazil and Paraguay.

The new virus is named after the Chapare River in the eastern foothills of the Andes.

(Editing by Philip Barbara)