January 1, 2007 Biochemists have developed a new tool that can identify a strain of influenza in hours, instead of the usual days or weeks, potentially speeding up the development of new vaccines. A sample of the infected patient's nasal or throat culture is deposited on a DNA microarray, where the flu's RNA binds to human DNA like a lock and a key. The match is then imaged using a fluorescent solution, and the entire procedure lasts less than seven hours.
BOULDER, Colo. -- Each year Americans rush to get their flu shots before they get sick. But what if the "bug bites" before the vaccine works?
A genetic revelation in science could save you from getting sick. Biochemists can now diagnose, treat, and develop vaccines against new strains of flu faster than ever before -- bioscience that could benefit people around the world.
"Last year ... of the human influenza viruses that were infecting people in U.S., 90 percent of them became resistant to an entire class of antiviral drugs that were very popular," Erica Dawson, of University of Colorado, Boulder, tells DBIS.
There, biochemists have developed a diagnostic tool that can identify a strain of influenza in hours, instead of the usual days or weeks. A robot carefully drops microscopic dots of human DNA on slides. The slide is then washed with a sample of the infected patient's nasal or throat culture.
Dr. Dawson says, "Where the influenza matches the sequence of DNA that is on the slide, we will get (clap) a sticking event" ... Fitting like a lock and key. "The third step in this process is the detection step, and that is when we take a solution," she says.
The pink florescent solution makes the DNA/virus match visible, and a computer identifies human or bird flu strains faster than ever before. Start to finish ... Seven hours.
Dr. Dawson says, "If something like the Flu Chip were to get in hands of epidemiologists and public health laboratories around the world, we could keep a better handle on what flu was, when and where."
And she says that tiny speck of information on a slide could help prevent flu pandemics worldwide.
The University of Colorado hopes to decrease the time it takes to perform the Flu Chip test by more than half. The goal is to make it possible for doctors to test, diagnose and prescribe for flu, in a one-hour office visit.
BACKGROUND: Scientists at the University of Colorado, Boulder, have developed a new flu-detector chip that can quickly determine the genetic signatures of specific influenza strains in samples taken from patients. The analysis can be completed within 11 hours, compared to other tests that take four days. While existing commercial rapid tests can detect the presence of influenza within an hour, those don't provide useful genetic information for identifying strains. The chip could also be easily reconfigured to test for the avian flu virus, as well as any other virus whose genes are encoded as RNA instead of DNA -- including SARS, measles, HIV and hepatitis C.
HOW IT WORKS: The flu chip fits on a standard microscopic slide and has rows of dots -- five in all, with three dots in each -- containing a specific sequence of DNA. During processing, RNA fragments from a "wash" of influenza gene fragments taken from a patient binds to specific DNA segments to indicate a match, much like a key perfectly fitting a lock. That RNA is then labeled with another DNA sequence containing a fluorescent dye that lights up when the chip is inserted into a laser scanner. The chip is currently about 90 percent accurate and is now being tested against standard testing methods used by the Center for Disease Control and Prevention. The Boulder scientists hope to make the process even faster by amplifying the telltale fluorescent signal, thereby shortening the test to as little as two hours. They also hope to downsize the technology into a handheld portable device the size of a cell phone or PDA.
PANDEMIC PANIC: Being able to determine the specific influenza strain in a sample may help world health officials combat future flu epidemics and pandemics. Strain identification is critical for tracking emerging strains and determining which flu strains are most likely to infect the population the following year in order to develop annual preventive vaccines. Historically, flu pandemics occur when a new strain of the flu virus emerges that is particularly contagious. They can cause millions of deaths worldwide, ranking a flu pandemic among the top four global risks listed by the World Economic Forum.
The American Meteorological Society contributed to the information contained in the TV portion of this report.
Editor's Note: This article is not intended to provide medical advice, diagnosis or treatment.