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CAHFS Virologists Must Keep up with New and Changing Diseases

March 24, 2015

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Dr. Beate Crossley uses real-time PCR for Avian Influenza diagnostics

Behind the scenes of the California Animal Health and Food Safety (CAHFS) Laboratory System, scientists are helping to protect animal health, public health and the food supply by rapidly detecting and responding to catastrophic and emerging livestock and poultry diseases.

Through a screening process using sensitive detection technology called PCR – or polymerase chain reaction - CAHFS Virologist Dr. Beate Crossley and her team are able to quickly and reliably identify a potentially dangerous virus. Rapid identification helps limit an infectious animal disease that could have devastating effects on both animals and humans.  

Limiting the spread of avian influenza

In January 2015, Dr. Crossley and her team diagnosed a highly pathogenic H5N8 avian influenza strain detected in a turkey from Stanislaus County, California.  The samples submitted were identified as high risk for avian influenza by astute diagnosticians working in the Turlock Branch Laboratory, one of four CAHFS laboratory facilities situated in California’s animal producing regions.  In February, a second flock was also identified from samples submitted to the CAHFS Tulare Branch Laboratory.  

Avian influenza is an example of a virus that can move over great distances in migratory waterfowl. Rather than mutating from a local virus, the origin of this highly pathogenic strain travelled from Southeast Asia to California in wild waterfowl. Because a highly pathogenic strain spreads quickly among birds and is difficult to contain, it poses a high risk to backyard poultry flocks and commercial operations, with devastating animal health and economic consequences. While this strain of avian influenza is not known to be a threat to public health, some strains can be transmitted to people, highlighting CAHFS’ important role in regularly monitoring these viruses in animals.

Early and rapid detection by CAHFS - designated as one of the core labs in cooperation with USDA and the National Animal Health Laboratory Network (NAHLN)) - is critical to limiting the spread of rapidly moving disease like avian influenza. As the only designated diagnostic lab to protect the state from foreign and emerging animal diseases, CAHFS routinely tests more than 20,000 samples each year specifically to detect avian influenza as early as possible.

Developing new tests for changing diseases

Outbreaks like avian influenza demonstrate the complexity of quickly diagnosing and controlling fast-moving viral diseases. Viruses can mutate very quickly to form new strains, which is why it is critical for CAHFS to have the resources to regularly evaluate the effectiveness of existing tests in order to assure a rapid diagnosis.

Until recently, available test methods focused on detecting viruses common to a region.  In order to stay on top of changes in avian influenza and because regulatory agencies rely on CAHFS, developing new tests is critical for responding to both foreign and domestic viruses.

“We must continuously develop new ways to detect emerging strains and genetic recombination in organisms with potentially serious consequences for human health,” said CAHFS Director Dr. Richard Breitmeyer.  

In the past, the team at CAHFS has been successful in quickly devising effective methods for responding to several high-profile animal health emergencies.  In 2001, a new test provided rapid detection of Exotic Newcastle Disease in backyard chickens, which led to a multimillion- dollar joint USDA/CDFA disease eradication effort. CAHFS performed more than 110,000 tests for the disease in ten months and shortened the time to reopen international markets and reduced the overall cost of the outbreak.  In 2008, they detected a very virulent form of infectious bursal disease virus in a commercial layer flock not previously documented in the United States.

As new diseases emerge, innovations in genetic diagnostic testing can help CAHFS differentiate between the wide spectrum of viruses. They can assist with detection and with efforts to effectively respond to outbreaks.

“There is so much out there we don’t know of yet.” said Dr. Crossley. “Detecting dangerous pathogens - like the recent highly pathogenic H5N8 avian influenza virus - serve as an important warning that these viruses must be constantly monitored for changes that could affect animals and humans.”