The Centers for Disease Control and Prevention and the University of Colorado at Boulder have developed a microchip-based test that distinguishes between flu strains and can even help trace the strains back to their origins.
The FluChip can be used to identify 72 influenza strains—including the H5N1 avian influenza strain that is currently of such concern—in fewer than 12 hours.
This technology can be used to make sophisticated influenza diagnostic capabilities more widely available to labs around the globe, not just concentrated with the CDC and a few major international laboratories.
"The ability to quickly and accurately identify strains of influenza would be invaluable to international flu surveillance efforts," said National Institute of Allergy and Infectious Diseases director Anthony Fauci.
The FluChip is a microarray, commonly called a gene chip. Microarrays can be made by using a robotic arm to drop hundreds or thousands of spots of genetic material—DNA or RNA—of known sequence onto a microscope slide.
The spots, called probes, are then exposed to a sample of unknown composition—for instance, material taken from a person with an undiagnosed illness.
Probes that match gene sequences of bacteria or viruses present in the sample result in capture of the target gene. By analyzing the pattern of captured targets, doctors can diagnose the cause of infection.
Researchers started with nearly 5,000 flu gene sequences, and then they used the data mining process to select 55 flu RNA sequences for use as probes on the FluChip.
The probes included ones to enable the detection of two of the most common flu strains currently circulating in humans, the H1N1 and H3N2 strains, as well as the avian flu strain H5N1.
Results after two rounds of tests showed that the FluChip led to the correct information about both type and subtype in 72 percent of samples.
Full information on type and only partial information on subtype was garnered for 13 percent of samples, while 10 percent of samples could be identified by type only with no information about subtype.
It took about 11 hours to conduct the tests.
"This state-of-the-art research is vital to our efforts to protect the nations health, and it may provide a new tool in our toolbox in the fight against influenza," said CDC director Julie Gerberding.