Currently, most flu strains go undiagnosed, or are identified in a laboratory miles from any doctor’s office. If the strain is diagnosed, the time between a nasal swab and a final read-out can be days if not weeks. Health care professionals need fast, accurate ways to distinguish one flu strain from another. Such tests are especially important to have on hand when new strains of influenza, such as the novel H1N1 strain of 2009, emerge.
Kathy Rowlen, Ph.D., formerly of University of Colorado at Boulder and now CEO of InDevR, is out to help. Dr. Rowlen and her colleagues developed a self-contained kit, smaller than a deck of cards, which can fully characterize an influenza virus in about an hour or so.
The device, called a “flu chip,” is based on DNA microarray technology, a research tool that enables scientists to analyze gene activity in cells and, more recently, to detect pathogens in a sample. Short, specially labeled segments of DNA are robotically placed in rows of microscopic spots on a glass slide. The DNA segments can capture telltale “signatures” of specific flu strains. When the viral RNA from a nasal swab meets up with the DNA spots, individual RNA strands will stick like Velcro to the DNA sequences they complement, causing them to glow bright yellow. The resulting pattern of glowing versus dark spots will reveal if it’s influenza A, B, or C, and, if it’s influenza A, whether the strain is H1N1, H5N2, H7N3, and so on. Such a device could also be used to diagnose SARS and other respiratory diseases.
One of the more important aspects of the flu chip is that it’s being developed to be used anywhere in the world, wherever there’s a potential outbreak. “The current microarray technology is wonderful in the hands of experienced experts in a very clean environment, but it’s not practical for going into the fields in, say, Madagascar,” says Dr. Rowlen. “We’re designing a technology and methodology that can be used in imperfect conditions.”The team, who were funded by a grant from NIAID, tested the chip in labs at the Centers for Disease Control and Prevention (CDC). In 2006, they reported that it was more than 90 percent accurate in detecting a strain of avian influenza, H5N1, and two common human flu strains, H1N1 and H3N2. “This was the first time a version of the flu chip was tested outside of our lab, and it exceeded our expectations,” says Dr. Rowlen.
In May 2009, Dr. Rowlen used a version of the flu chip that tests for the influenza matrix (or M) gene on non-infectious samples of the novel 2009 H1N1 influenza virus that were provided to her by the CDC. The M version of flu chip successfully detected the 2009 H1N1 virus signature in all of six samples tested. Moreover, the flu chip distinguished between the 2009 H1N1 virus and seasonal influenza viruses including human H1N1 and H3N2.
NIAID provided funding to InDevR to develop flu chip test kits for use by the Colorado Department of Public Health and Environment to address diagnostic needs arising from the outbreak of novel H1N1 influenza.
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Last Updated June 24, 2009