On Nov. 1, 2021, for the first time in the U.S., the transmission of COVID-19 from pet parent to pet was documented genetically as part of a study by the Translational Genomics Research Institute (TGen), an affiliate of City of Hope.

The published findings from the ongoing study appear in the journal One Health. This is one of five pilot studies nationwide examining COVID in animals. The TGen study, however, is the only one to include genomic sequencing of the virus from both pet and human samples. This level of testing resulted from TGen’s overall efforts to monitor the virus and its potentially more-dangerous variants by sequencing as many positive human samples of the virus as possible.

TGen’s COVID animal study is conducted under a grant from the Arizona Department of Health Services (ADHS). As with the other pilot studies, the funds come from the U.S. Centers for Disease Control and Prevention (CDC) in coordination with the Council of State and Territorial Epidemiologists (CSTE).

In the Arizona case study, the pet owner, cat and dog all were infected with the identical strain of coronavirus: B.1.575, an early and unremarkable version of SARS-CoV-2, the virus that causes COVID. Fewer than 25 documented cases exist of Arizonans infected with this strain, according to information drawn from the COVID variant tracking dashboard that TGen maintains for the CDC and ADHS. To date, more than 46,000 positive samples of Arizonans with COVID have been sequenced.

Researchers deduced that the virus spread from the pet parent to either the dog or cat, or both. The animals were confined to an apartment and therefore had little-to-no opportunity to be exposed to the virus, and so it was highly unlikely that the pets infected their owner. Plus, in each case examined in the study, it was the pet parent who exhibited COVID first. Worldwide, there is no documented case of COVID transmission from a pet to its pet parent.