The first dog in the US to test positive for COVID-19 has passed away.

Buddy, 7-year-old German Shepherd started to show symptoms mid-April when he began struggling to breathe, and was tested positive for COVID-19 six weeks later.

His owner, Robert Mahoney from Staten Island, New York, believes his pooch caught the virus from him, but it is unclear whether Buddy died from complications of the coronavirus or whether he died from a type of cancer.

Buddy’s medical records were reviewed by two veterinarians who were not involved with his treatment, and declared that he might had lymphoma, a type of cancer.

The veterinarians believe that the findings would explain the symptoms Buddy suffered from before he passed away.

Mahoney was not aware that lymphoma was being considered as the probable cause of his dog’s demise until the day of his death, when additional bloodwork was done and confirmed it.

This puzzled the experts more, as it is unclear whether cancer made Buddy more susceptible to contracting the coronavirus, or if the virus made him ill, or his entire ordeal is a case of a coincidental timing.

Buddy’s unfortunate fate, like many who struggles with the effects of the coronavirus around the world, left many questions but few answers.

Meanwhile, Buddy’s younger brother, Duke, is also believed to have contracted the virus.

Duke tested negative for the virus and had not shown symptoms, but antibodies against the pathogen was found in his bloodwork, which indicates that he had been previously infected.

When Mahoney suspected Buddy had contracted the virus, it took them a while before finding a veterinarian who would test him and confirmed Mahoney’s suspicion.

“You tell people that your dog was positive, and they look at you (as if you have) ten heads,” Mahoney’s wife, Allison said in an interview.