in 2009, two teenagers in the Democratic Republic of Congo showed up at
their village health clinic, vomiting and with blood in their noses and
mouths — hemorrhagic symptoms of the notorious Ebola viruses. In three
days they were dead.
Yet it took three years for researchers to unmask the likely culprit: a brand-new virus called Bas-Congo, which is not related to Ebola or any other virus known to cause severe hemorrhagic fever.
It can take weeks or months to identify a novel virus, and
much longer if the sample must be sent to a specialized lab, as the
Bas-Congo virus was. Such lags are too long, says virologist Charles
Chiu, director of the Viral Diagnostics and Discovery Center at the
University of California in San Francisco.
Deciphering a virus’s genetic code is the critical first
step in determining how fast it might spread, identifying possible
treatments and even finding vaccines. Viruses like the one that killed
the Congolese teens can quickly go global, and traditional methods for
identifying viruses, which only test for one pathogen at a time, could
mean sacrificing untold lives.
But Chiu and his colleagues have found a way to speed up virus identification — a method
they hope will one day help health care workers in remote areas
identify new viruses as soon as they appear, as long as they are able to
access the Web.
The team conducted a proof-of-concept test in which they eventually identified the Congolese virus.
Typically, it takes three months to piece together a
complete viral genetic code. The new process can identify an unknown
virus in less than two hours, and Chiu’s team can put together the
entire genetic code of a virus in a single day.
Chiu’s colleagues are working to get more DNA sequencers —
and expertise to use them — into the hands of health care workers in
potential virus hotbeds. Meanwhile, Chiu and his team hope to put their
virus-identifying system on the Web so health workers anywhere can
Chiu’s vision: When patients show up at a clinic with an
unknown pathogen, health care workers could take swabs and run DNA
sequences onsite, then use smartphones or laptops to feed the results to
an online network that would deliver results in minutes.
[This article originally appeared in print as "The Race to Peg a Virus."]
1. Starting with a sample of the Bas-Congo virus, Chiu and colleagues
first grew the virus in culture, then extracted its genetic material
and made millions of copies.
2. Next, they put the samples into an instrument called a DNA
sequencer — which automatically analyzes genetic material — to read
short viral gene fragments millions or even billions of times.
3. Finally, they ran the results through a software program that
combed through many gene sequences simultaneously, comparing each one
with the sequences of known viruses stored in online databases. This
process allowed them to home in on the identity of the virus.