New Flu Test Will Expand, Speed Diagnoses

By Charlene Porter
Washington File Staff Writer

Washington – U.S. government and academic researchers have come up with a new method to identify influenza viruses that will speed the identification process and allow more labs to determine where viruses come from and how dangerous they are.

The U.S. Centers for Disease Control and Prevention (CDC) August 28 announced the new test, developed in partnership with scientists from the University of Colorado at Boulder.

The FluChip, a microchip-based test, distinguished among 72 influenza strains – including the H5N1 avian influenza strain – in fewer than 12 hours, according to a CDC press release.

Basic identification of a virus type and subtype can be conducted at many laboratories in the developed and developing world. But only a relatively small number of laboratories have high-level biosafety facilities that can determine if a virus comes from a human or nonhuman source and whether it is related to recognized viruses or is becoming more virulent.

“The ability to quickly and accurately identify strains of influenza would be invaluable to international flu surveillance efforts,” said Dr. Anthony S. Fauci, director of the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, the organization that funded the research.

The limited number of worldwide facilities capable of performing the complete array of complex tests has caused routine delay in confirming human cases of H5N1.

Days can pass as samples from an individual suspected to have H5N1 are transported from sometimes-remote areas to qualified laboratories.

Accurate identification of a particular viral strain can influence other critical health policy decisions, such as quarantine or the distribution of anti-viral drugs to other vulnerable people, so timeliness in diagnosis is important.

The CDC and University of Colorado researchers are attempting further refinement of the methods to produce results in as little as one hour.


The World Health Organization (WHO) is issuing guidelines for medical practitioners to follow while identifying a person who is a suspected, probable or confirmed case of the H5N1 avian influenza strain.

The U.N. health agency took this step August 29 to ensure the use of standardized language for communication among health authorities dealing with the avian influenza outbreaks at different times and in different places.

The guidelines define a suspected H5N1 case as a person who has a fever and respiratory symptoms and also has had close contact with a person known to have H5N1, or contact with contaminated birds, or has consumed raw or undercooked poultry in an area where H5N1 has been confirmed or suspected in recent days.

A probable H5N1 case will meet all the criteria of a suspected case, but also will have evidence of acute pneumonia and respiratory failure.

Laboratory confirmation of the presence of an influenza type A infection, even though the subtype may be unconfirmed by more sophisticated tests, also will be considered adequate evidence to call a case probable, according to the new guidelines.

A case will be confirmed only with proper sample testing at a certified laboratory, according to the WHO guidelines.


The highly pathogenic avian influenza strain H5N1 has been detected in wild and domestic bird populations in more than 50 countries but still has not appeared in the United States.

The U.S. Department of Agriculture (USDA) confirmed August 28 that some wild mute swans tested earlier in the month showed no sign of the dangerous strain that has killed an estimated 200 million birds in the almost three years since it first appeared in Southeast Asia.

The USDA announcement says low-pathogenic strains of bird flu in wild birds are not unusual.

The “low-path” strains are much different from the other types of the virus, do not circulate as rapidly, and frequently have no adverse effects on wild birds.

The USDA and the Department of the Interior are working with state-level agencies to conduct rigorous testing of wild bird populations that are thought to be carriers of the virus.

For ongoing coverage, see Bird Flu (Avian Influenza).