Fifty dogs, 28 cats, and one rabbit in Spain were tested for COVID-19 during their owners’ quarantine between December and March. None displayed symptoms, and only a tenth tested positive, researchers wrote in the study, published Wednesday to research preprint site medRxiv. In those who tested positive, viral counts were low, making the pets less likely to spread the sometimes deadly virus.

Other studies have found that other COVID variants like Alpha and Delta were more easily transmitted to household pets, that infected pets were more likely to show symptoms, and that higher viral loads were detected in the pets.

With new COVID variants come concerns about potential transmission from humans to other species, like household pets, in which the virus could evolve and mutate in to a more dangerous strain.

The study’s findings on Omicron in household pets contrast with a study on Omicron in minks published earlier this year. It found rampant spread of Omicron among minks, many of whom had symptoms and some of whom developed lesions. White-tailed deer have also been found to be highly susceptible to Omicron, though their contact with humans is infrequent, the study said.

COVID has been found in wild leopards, hyenas and hippos at zoos, and pet ferrets and hamsters, and spreads rapidly in some species such as minks and white-tailed deer. A broader swath of animals may be susceptible to Omicron, which has been found in turkeys, chickens, and mice, when compared to previous COVID variants, according to Nature.

COVID is thought to have originated in bats before being transmitted to humans via civet cats: nocturnal creatures related to the mongoose that live in Europe, Asia, and Africa. MERS, another coronavirus first identified a decade ago, is thought to have originated in camels, according to a 2021 paper published on the U.S. National Institutes of Health’s National Library of Medicine website.