University of California, Davis
February 1, 2006
A new test that promises a speedier, more accurate diagnosis of a highly contagious form of influenza in dogs has been developed by researchers at the University of California, Davis, who say it is now available to veterinarians throughout the state.
The new test, based on polymerase chain reaction, or PCR, technology, can provide results within 24 to 48 hours, according to researcher Christian Leutenegger, who created the new test at UC Davis' School of Veterinary Medicine. With current testing techniques, it can take several days for a diagnosis.
The University of California has applied for a patent on the new test, which is being used today for diagnosing canine influenza at UC Davis' Lucy Whittier Molecular and Diagnostic Core Facility.
"By analyzing the RNA collected on a swab from the dog's throat, this test provides the quickest and most accurate test for canine influenza now available," said Leutenegger, who directs the diagnostic facility. "We have alerted veterinarians throughout California that the test is available." He notes that swab samplings should be taken within 72 hours after the dog exhibits symptoms of the illness.
The PCR method is an extremely sensitive test that can detect small amounts of the virus's genetic material in the sample collected on the swab. The PCR process uses an amplification technique that multiplies the existing DNA or RNA so that it can be identified more easily.
Prior to development of this test, veterinarians relied on serum antibody tests to diagnose canine influenza. The drawback of such blood tests is that they cannot detect the disease until the dog begins to produce sufficient antibodies to the virus, which may be several days after symptoms appear.
Canine influenza is an upper respiratory disease, first reported in January 2004 in racing greyhounds at a Florida racetrack. To date, antibodies to canine influenza virus have been detected in dogs in animal shelters, adoption groups, pet stores, boarding kennels and veterinary clinics in 19 states.
The viral disease, which appears in mild or severe forms, is an H3N8 type of flu that is closely related to influenza in horses.
Veterinary researchers report that it is spread much the way other influenzas are spread -- through exposure to droplets of fluid that are dispersed by coughing. Dogs can also catch the virus from saliva or mucus on shared toys or food dishes.
There is no evidence that canine influenza can be passed to humans.
Because this virus is just now emerging, dogs have no natural immunity to it. All dogs exposed will become infected, and about 80 percent of the infected dogs will develop symptoms of the illness.
Dogs with a mild case of the disease will likely have a persistent cough that sometimes mimics the bacterial disease known as "kennel cough" and may also have a thick nasal discharge.
In more severe cases of canine influenza, dogs may develop high fevers and pneumonia. The disease appears to kill 5 to 8 percent of the infected dogs.
There is currently no vaccine available for canine influenza; veterinarians treat infected dogs with supportive care so that their immune systems can fight off the disease. Antibiotics may be given to deal with secondary bacterial infections, and fluids may be administered to prevent dehydration.
More information about UC Davis' new PCR test for canine influenza is available online at <http://www.vetmed.ucdavis.edu/vme/taqmanservice/>.
* Christian Leutenegger, School of Veterinary Medicine, (530) 754-5342, firstname.lastname@example.org
* Jane Sykes, School of Veterinary Medicine, (530) 752-1393, email@example.com
* Pat Bailey, UC Davis News Service, (530) 752-9843, firstname.lastname@example.org