SARS-CoV-2 likely first jumped from animals to humans in late 2019, sparking the pandemic in Wuhan, China. The findings suggest that the coronavirus jumped back and forth between people and mink, in the first known published case of animal-to-human, or zoonotic, transmission, according to the authors. The third study, which will also be presented at the ESCMID conference, involved monitoring COVID-19 infections at 16 mink farms with more than 720,000 animals in the Netherlands. COVID-19 infections identified in dogs as part of this testing were reported in a study published on May 14 in Nature-the first published evidence of the disease in dogs. The pets are isolated until they test negative on RT-PCR on two occasions. The Agriculture, Fisheries and Conservation Department of Hong Kong quarantines and tests pets from infected households or their close contacts in a holding facility if other care is not available. The researchers called for broader serologic surveillance of cats connected to COVID-19 patients to determine the prevalence of human-to-cat spread.
In support of these findings, the cat had no outdoor access." "The timeline of infection in cat 1 and the finding of an identical SARS-CoV-2 genome sequence in a human from the same household is consistent with human-to-animal transmission. "Although feline-to-human transmission is theoretically possible, we did not find any evidence of this transmission," the authors said. The researchers were unable to grow the virus on cell culture. All cats were asymptomatic but had lung abnormalities similar to those of infected humans. Six of the 50 cats (12%) tested positive for SARS-CoV-2 RNA on RT-PCR, and virus genomes from one owner-and-cat pair were identical. In the second study, a research letter published yesterday in Emerging Infectious Diseases, researchers in Hong Kong tested the respiratory and fecal samples of 50 cats from COVID-19–infected households or their close contacts for coronavirus RNA from Feb 11 to Aug 11. "There is sufficient evidence from multiple studies, including ours, to recommend that SARS-CoV-2 infected persons should isolate from people and animals," she said. In the meantime, Bienzle said, pet owners infected with COVID-19 should isolate themselves. Lead author Dorothee Bienzle, DVM, PhD, of the University of Guelph, said in an ESCMID news release that blood testing the animal after the owner recovers is the best way to assess human-to-animal transmission because the window of time to identify current infections in pets is narrow.
The authors noted previous reports of SARS-CoV-2 infections in different animal species, but none have identified risk factors for or clinical characteristics of infection. One dog had previously had displayed respiratory symptoms. Two of 10 dogs with blood samples (20%) had coronavirus antibodies. The owners of all cats with inconclusive COVID-19 tests or positive antibody results said they and their pets had displayed coronavirus-like respiratory symptoms at the same time. Overall, seven of eight cats with blood samples (88%) had coronavirus antibodies. The results were compared with those of stored blood samples collected from animals before December 2019.Īll animals tested negative for SARS-CoV-2, the virus that causes COVID-19, on reverse transcription polymerase chain reaction (RT-PCR), except for one cat, which had ambiguous results but tested positive for coronavirus antibodies, indicating previous infection. If more than 2 weeks had passed, the pets were tested for antibodies. The study, which will be presented at the Sep 23 to 25 virtual European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Conference on Coronavirus Disease, involved collecting nose, throat, and rectal swabs from 17 cats, 18 dogs, and 1 ferret owned by people diagnosed as having COVID-19 or reporting symptoms consistent with the coronavirus in the previous 2 weeks.
The first, a small, unpublished study from the University of Guelph in Ontario, Canada, suggests that a large proportion of pet cats and dogs may have gotten COVID-19 from their owners, as evidenced by antibodies against the coronavirus in their blood. Three new studies suggest that high proportions of cats and dogs may have acquired COVID-19 from their owners and that the virus jumped back and forth between humans and minks on farms in the Netherlands.