A virus that killed two teenagers in Congo in 2009 is a completely new type, related to rabies but causing the bleeding and rapid death that makes Ebola infection so terrifying, scientists reported on Thursday. They’re searching for the source of the virus, which may be transmitted by insects or bats.
The new virus is being named Bas-Congo virus, for the area where it was found. Researchers are finding more and more of these new viruses, in part because new tests make it possible, but also in the hope of better understanding them so they can prevent pandemics of deadly disease.
The virus infected a 15-year-old boy and a 13-year-old girl in the same village in Congo in 2009. They didn’t stand a chance, says Joseph Fair of Metabiota, a company that investigates pathogens. Fair is in the Democratic Republic of Congo now, under contract to the U.S. Agency for International Development (USAID) to help battle an ongoing Ebola outbreak.
“They expired within three days,” Fair said in a telephone interview. “It was a very rapid killer.”
A few days later a male nurse who cared for the two teenagers developed the same symptoms and survived. Samples from the lucky nurse have been tested and it turned out a completely new virus had infected him, Fair and other researchers report in the Public Library of Science journal PLoS pathogens.
The DNA sequences went to Dr. Charles Chiu, of the University of California, San Francisco.
“We were astounded that this patient had sequences in his blood from a completely unknown and unidentified virus,” Chiu said. They weren’t expecting that.
“Congo is very much known for having Ebola and Marburg outbreaks. Yet about 20 percent of the time we have hemorrhagic fever outbreaks that are completely negative, which means unknown causes and they are not Ebola.”
The sequencing puts this new virus on its own branch of the bad virus family tree -- somewhat related to Ebola and the virus that causes Lassa fever, another horrific killer, and most closely related to the rhabdoviruses. This family usually only infects animals with one notable exception -- rabies.
But rabies is not known to cause hemorrhaging. It’s plenty horrible on its own, of course, killing virtually all patients if they aren’t vaccinated soon after infection.
A nurse who took care of the first infected nurse had antibodies to the new virus. It doesn’t look like the teenagers infected one another, says Fair, but they probably infected the first nurse, who probably infected the second. Tests of other villagers have found no more evidence of the virus, however, which is good news.
“Although the source of the virus remains unclear, study findings suggest that Bas-Congo virus may be spread by human-to-human contact and is an emerging pathogen associated with acute hemorrhagic fever in Africa,” the researchers wrote.For more on this new virus, see NPR's health blog Shots, MedicalXpress, and ScienceNow.