WSU laboratory begins limited testing for COVID‑19 virus

WADDL's laboratory where testing will occur.

PULLMAN, Wash.— The Washington Animal Disease Diagnostic Laboratory (WADDL), on the Washington State University campus in Pullman, has begun limited testing of animal samples for the SARS-CoV-2 virus, the causative agent for COVID-19.

Currently, the test is only available for agencies and academic institutions.  The current testing was not developed with, and does not use, human health testing resources. No additional personal protective equipment (PPE) is necessary for the testing program as designed in a coordinated effort with the nation’s animal disease diagnostic laboratories.

So far WADDL has tested two cats. Both results were negative for the COVID-19 virus.

The first was a cat necropsied and tested at the request of another state’s agency that lived with a human diagnosed with COVID-19.  This cat’s death was unrelated to the COVID-19 virus.  Necropsy revealed the animal had a common feline heart disease that causes abnormal thickening of the organ’s walls (hypertrophic cardiomyopathy).  When this condition occurs, the heart labors to pump blood easily and eventually fails. WADDL tested 23 tissues and the cat’s feces.  All tests were negative for SARS-CoV-2 by testing known as real time polymerase chain reaction (RT-PCR), which was specifically developed for the project by WSU.

The second case tested at the request of a state agency is a cat that is living with no signs or symptoms of disease.  The cat was quarantined with its owner who was diagnosed with COVID-19.  Nasal and throat swabs from this cat tested negative for SARS-CoV-2 by RT-PCR; similar results were obtained from USDA’s National Veterinary Services Laboratory (NVSL) with further tests pending.

WADDL developed and validated the specific laboratory test at the request of federal, state, and county animal and public health agencies.  WADDL is assisting in the response to this disease by testing certain animals upon request of agencies responding to the emergency.

A second and perhaps more important goal for the current WADDL testing is to begin collecting valuable scientific data for further study especially if animals are determined to be carriers for SARS-CoV-2.

The question of infection in animals is important because in a study done in 2003 with the previous SARS outbreak, domestic cats and ferrets could be infected with the SARS (severe acute respiratory syndrome) coronavirus and could pass it to other cats and ferrets.  Disease experts would like to know if this is a possibility for the current virus causing COVID-19, which has added to the reasoning for testing pets for agencies by WADDL.

The WADDL test identifies the COVID-19 virus without cross-reacting with other common, naturally occurring respiratory viruses in dogs and cats. Coronaviruses, named for the crown-like spikes found on their surface, carry their genetic material in single strands of RNA (rather than DNA).

The WADDL test uses a technique called a real time polymerase chain reaction test (real time PCR) to detect the presence of a unique fingerprint of COVID-19 virus RNA.  The process transforms very small quantities of the RNA from the virus into very large amounts of DNA which can then be easily detected using specialized equipment. WADDL also performs targeted genetic sequencing to verify the real time PCR results and further increase the accuracy of the overall testing plan.

Testing first involves securely collecting swabs from around the external openings of the animal’s nose and from the back of the mouth near the throat by qualified veterinarians as approved by the State Veterinarian.  Once securely collected, samples are securely packaged according to federal regulations for biological materials shipment and transported to WADDL. Testing currently is done twice weekly however WADDL has the capacity to scale up if necessary, potentially even turning emergency sample results within two hours.

The testing plan, real time PCR and targeted genetic sequencing, will accurately identify COVID-19 virus genetic material, but does not determine whether or not the virus is alive.

WADDL is a Level 1 laboratory in the USDA National Animal Health Laboratory Network (NAHLN) and any animals identified positive for SARS-CoV-2 by WADDL will be confirmed by the USDA-NAHLN national reference laboratory. Positive results for SARS-CoV-2 in animals will be reported to the submitting party and the State Veterinarian where submitting party resides since any COVID-19 virus identified in animals is reportable to the World Organization for Animal Health (OIE). In this way, information regarding any COVID-19 virus identified in animals can be shared around the world for combatting the global COVID-19 pandemic.

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