A pet dog in the US has tested positive for coronavirus.

The pooch, a pug called Winston, was assessed for the virus through a study at Duke University, in North Carolina, after three members of the same family all tested positive for COVID-19.

Dr Chris Woods, principal investigator of the Duke study, said he believes it is the first known positive case in a dog in the country.

The family's mother, Heather McLean, who is a paediatrician at Duke and also came down with the virus, said the dog was experiencing mild symptoms.

Winston the pug is the first dog to test positive for coronavirus. (iStock)

"Pugs are a little unusual in that they cough and sneeze in a very strange way. So it almost seems like he was gagging, and there was one day when he didn't want to eat his breakfast, and if you know pugs you know they love to eat, so that seemed very unusual," she said.

"(The dog) licks all of our dinner plates and sleeps in my mum's bed, and we're the ones who put our faces into his face. So, it makes sense that he got (coronavirus)," Ms McLean's son, Ben, said.

The McLeans have four pets: two dogs, a cat and a lizard. The family said the dogs and cat were tested and only Winston tested positive.

They took part in the Molecular and Epidemiological Study of Suspected Infection (MESSI) research study on April 1.

"They all came out to our house and did blood samples," Ms McLean said.

"For the humans, they swabbed our noses as well as our mouths, and for the animals they did oral swabs for both dogs and the cat."

The McLean's daughter, Sydney, was the only member of the family not to test positive for COVID-19. The family's father, Samuel, works in the emergency room at UNC Hospitals.

The family said Winston was only sick for a few days and is doing much better.

"Hopefully we'll learn more through the research study, and I think because there's not a lot of studies and sampling pets, we just don't know yet. My advice is just not to get too worried about it," Ms McLean said.