Bas-Congo virus after the province where it was found just west of Kinshasa, the teeming capital of the Democratic Republic of Congo. The discovery was announced today in the journal PLoS Pathogens. So far only three people in the remote village of Mangala are known to have contracted Bas-Congo hemorrhagic fever, two of whom died. One was a health care worker who cared for the other two villagers, which means it can apparently be transmitted from person to person, although no one knows how easily. But the small number of known cases is actually one of the important things about this finding. It signifies that scientists may have found an emerging disease very soon after it made its jump from whatever species it came from into humans. We’ll come back to its most likely origins a little later. The reason for thinking Bas-Congo only recently began infecting humans is that researchers have run blood tests on people throughout the DRC and found no evidence of antibodies that would indicate any of them has been exposed to the new virus. “It doesn’t appear to be widespread throughout the Congo,” study co-author Charles Chiu of the University of California San Francisco told Shots. He says the team is planning to do more blood tests on people in the DRC and neighboring countries, such as Congo-Brazzaville right next to Bas-Congo province. “I would say we caught it fairly quickly,” said another study author, Joseph Fair, in a telephone interview from the other side of the DRC, where he’s helping to track down the origin of an ongoing outbreak of Ebola hemorrhagic fever that has so far afflicted 51 people and killed 20.
“This wasn’t HIV, where we’re 15 years into a pandemic before we actually find that we have a pandemic,” says Fair, who’s with a group called Metabiota that contracts with governments and health agencies to track disease outbreaks. The three known cases of Bas-Congo fever actually occurred three years ago. But tissue samples from the victims languished in a laboratory freezer in Kinshasa until an astute doctor called the cases to Fair’s attention. That time lag, along with the inability to keep some tissue samples from thawing out, has hampered the researchers’ ability to track the virus through other possible cases in Mangala village. There are some other striking things about the new virus. It doesn’t belong to any of the four families of previously known hemorrhagic viruses – Arenaviridae, Bunyaviridae, Filoviridae and Flaviviridae. These families harbor such notorious bugs as Ebola, Marburg, Lassa fever, Crimean-Congo hemorrhagic fever, dengue fever and Rift Valley Fever. Instead, Bas-Congo belongs to the Rhabdovirus family, which has never been known to include human hemorrhagic fever viruses, although it does contain one that affects fish. “That in itself is astonishing,” Chiu says, “but even within the rhabdovirus family, it’s very divergent.” That is, it doesn’t resemble any other rhabdovirus.