USDA: NC pug never contracted COVID-19

The United States Department of Agriculture, which oversees the NVSL, said a series of tests were conducted over several weeks after Duke researchers positively identified SARS-CoV-2 -- the virus that causes COVID-19 -- in Winston's oral swab.

"While there was a weak detection from the original oral sample, it did not meet the case definition for a positive, and all other testing was negative," said Lyndsay Cole, a spokesperson for the USDA's Animal and Plant Health Inspection Service.

“No virus was isolated, and there was no evidence of an immune response using the available test," said Cole.

The dog and all four members of the McLean family were tested on April 1 at their home in Chapel Hill as part of Duke University's Molecular Epidemiological Study of Suspected Infection (MESSI).

Heather McLean, a doctor at Duke, said she and her husband, a doctor at UNC, tested positive for COVID-19 in March. They found out through the study that their son also contracted the virus.

The McLeans found out about Winston's positive results in late April.

"We weren't really sure either way. We were curious just like everyone else," said Heather McLean, when finding out about Winston's negative results. "Did he have the infection or did he just have the virus in his mouth?"

McLean said it's possible the detection in Winston's original swab test was caused by the dog coming in contact with an infected surface or family member.

The USDA said additional samples, including swabs and a blood test, were taken from Winston on April 30. The McLean's second dog and cat were tested on May 13. Those results came back negative.

The NVSL has only confirmed SARA-CoV-2 in four pets nationwide, including two cats, a lion and tiger.

Elizabeth Petzold, program manager for Duke's MESSI, said researchers detected COVID-19 in two of the McLeans dogs but serology testing found neither of the animals developed an antibody response.

"It seems more likely that the virus was picked up by the animals via environmental contamination from the surfaces in the home. Going forward, we will begin collecting a small blood sample on all animals in the study to see if we can detect any animals with antibodies.  We hope to learn more as the study progresses.”