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A New, Rapid Laboratory Test for Avian Influenza in the Live Bird Market

A strain of avian influenza that has been endemic in live bird markets can now be detected quickly using a new laboratory test developed by an Agricultural Research Service scientist.

ARS veterinary medical officer David Suarez developed the test to quickly identify birds infected with the avian influenza strain H7N2, which has been found among birds in northeastern U.S. markets since 1994. Live bird markets in New York City and other areas sell a broad variety of poultry.

The laboratory test, called the real-time reverse transcriptase-polymerase chain reaction test (RT-PCR), uses a fluorescent probe and produces results in less than 3 hours.

For poultry, influenza infections can range from mild to severe, causing production losses or, in severe cases, sickness and death. The deadly form is called highly pathogenic avian influenza (HPAI). The mild form is hard to differentiate from other, more common health characteristics in a flock. Suarez's test uses the virus's genetic code to identify it.

In Virginia recently, a mild form of avian influenza infected 197 flocks, forcing authorities to humanely euthanize 4.5 million birds as a precaution. The virus remained as a mild strain, but had the potential to mutate and decimate flocks in as little as a week.

Live bird markets in Florida and the northeastern United States serve as central mixing areas for avian influenza viruses. The markets can harbor viruses and act as virus "reservoirs" from which the disease organisms can spread to larger commercial facilities.

The mild form H7N2 virus has been found in commercial poultry operations at least three times in the last five years, causing disease and serious economic losses for the industry. A 1983 outbreak cost $63 million in federal funds and $350 million in increased consumer costs. This new test may aid in identifying the viruses earlier and with more accuracy, therefore helping to control the disease and reduce such economic losses.

Read more about this research in the February issue of Agricultural Research magazine.

ARS is the chief scientific research agency of the U.S. Department of Agriculture.