A team of disease hunters has announced the discovery of a deadly new virus, found in a remote village in South America. Experts say the virus – named Chapare – is probably limited to a small swathe of Bolivia, but urbanisation and climate change could expand its range.

“These pathogens will markedly increase the risk of outbreaks with significant loss of human life,” says Stefan Kunz, a virologist at Centre Hospitalier Universitaire Vaudois in Lausanne, Switzerland, who was not part of the study.

On 4 January 2003, a young farmer and tailor from the Bolivian village of Samuzabeti developed fever and headache. Over the following days, the 22-year-old’s muscles and joints started throbbing, and he began vomiting and haemorrhaging blood. Two weeks later, he was dead.

Mystery virus

A local doctor, Simon Delgado, had no idea what had killed the patient; tests for known infectious diseases such as dengue and yellow fever turned up negative. As a precaution, Delgado sent specimens to the US Centers for Disease Control and Prevention (CDC) in Atlanta.


There, researchers in the agency’s special pathogens branch unpacked the sample in their most secure laboratory.

“When you suspect hemorrhagic fever, for safety reasons you have to work in a lab with high containment,” explains CDC’s Pierre Rollin. He and his colleagues donned ventilated full-body suits when working on the deadly virus – the same precautions taken to study Ebola.

A new beast

The CDC laboratory confirmed they were dealing with something never seen before. Tests on even the most obscure pathogens all turned up negative, Rollin says. When the researchers squirted the patient’s serum sample onto human cells growing in a Petri dish, a virus started multiplying. Rollin’s team dubbed it Chapare, after the victim’s home province.

Further tests confirmed that this Chapare virus was a new beast, part of a deadly family called arenaviruses. In West Africa, the related Lassa virus infects about 300,000 to 500,000 each year, killing 5000, according to the World Health Organization. The South American forms are rarer, but far deadlier.

“Quite often it’s a severe disease, maybe in 30% of cases you have a fatal outcome,” Rollin says.

There have been no human cases of Chapare virus since. Researchers at CDC hope to identify the virus’s host – probably a rodent – and determine the virus’ prevalence.

Charles Fulhorst, an arenavirus expert at the University of Texas Medical Branch in Galveston, says Chapare is the tip of the iceberg. Many new species of virus lurk in South America – and perhaps North America. “Just when you think you know what’s out there, another one pops out,” he says.

Rollin agrees and calls for more lab and field work to get a handle on Chapare. “There are lot of arenaviruses we don’t know,” he says. “Are they going to be the new pandemic virus that’s going to wipe out the planet? I don’t think so, but they could be a local problem.”

Journal reference: PLoS Pathogens (DOI: 10.1371/journal.ppat.1000047)