A joint team from the University of Colorado and the Centers for Disease Control and Prevention (CDC) have developed a microchip-based test that will enable more laboratories across the United States to carry out basic tests to determine the type and subtype of an influenza virus within several hours.

Lead researcher Kathy L. Rowlen, Ph.D., from the University of Colorado, says the FluChip successfully distinguished 72 influenza strains-including the H5N1 avian influenza strain, in less than 12 hours.

Because the FluChip technology is able to be used in lower level biosafety facilities more labs can be used to determine the geographic origin of a newly emergent virus.

It can also tell whether the source is human or nonhuman and how closely related a new virus is to ones that circulated previously.

It is also to able to detect any genetic changes that may signal the virus is becoming more virulent.

The FluChip is something called a microarray or a gene chip, which is made by dropping hundreds or thousands of spots of genetic material onto a microscope slide.

The spots or probes are then exposed to a sample of unknown composition, possibly material taken from a person with an undiagnosed illness.

By analyzing the pattern of captured targets, doctors can diagnose the cause of infection.

Beginning with a pool of nearly 5,000 flu gene sequences, the investigators selected 55 flu RNA sequences for use as probes on the FluChip.

Among them were probes chosen to enable 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.

The CDC provided the flu strain samples which included flu strains that infect humans, horses, birds and swine.

The CDC also shared its technical expertise on influenza and worked alongside University of Colorado staff in CDC laboratories to process the influenza samples, test the FluChip technology and analyze the results.

The promised rapid and detailed diagnosis will mean public health officials investigating a bird flu outbreak will have far more information at hand before they initiate steps to cull flocks of birds or to treat hundreds of potentially exposed people with expensive antiviral drugs.

At present samples are frozen and shipped to a highly secure laboratory where the virus can be genetically sequenced, a process can take more than a week to complete.

NIAID Director Anthony S. Fauci, M.D.says the ability to quickly and accurately identify strains of influenza would be invaluable to international flu surveillance efforts.

CDC Director Julie Gerberding, M.D.has praised the collaboration between governmental and academic researchers.

The research was funded by the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), and appears in the current issue of the Journal of Clinical Microbiology.