COVID-19 is likely to spread from humans to animals and vice versa

Three new studies suggest that the majority of cats and dogs may have obtained COVID-19 from their owners, suggesting that the virus traveled between humans and mink on Dutch farms.

SARS-CoV-2 antibody for dogs and cats

First, small, unpublished Investigation Researchers at the University of Guelph in Ontario, Canada, suggest that the majority of domestic cats and dogs may have obtained COVID-19 from their owners, as evidenced by antibodies to coronavirus in the blood. doing.

The study was presented at the Virtual European Society for Microbial Infectious Diseases (ESCMID) Conference on Coronavirus Disease, September 23-25, and is owned by 17 cats, 18 dogs, and 1 ferret. Included collection of nose, throat, and rectal swabs. Those who have been diagnosed with COVID-19 or who have reported symptoms consistent with the coronavirus in the last two weeks.

After more than two weeks, the pet was tested for antibodies. The results were compared with the results of stored blood samples collected from animals before December 2019.

All animals cause COVID-19 in reverse transcription-polymerase chain reaction (RT-PCR), with the exception of one cat, which showed ambiguous results but was positive for coronavirus antibodies that previously indicated infection. It was negative for the virus SARS-CoV-2. Overall, 7 (88%) of the 8 cats with blood samples had coronavirus antibodies. All cat owners with a definitive COVID-19 test or positive antibody results said they and their pets simultaneously exhibited coronavirus-like respiratory symptoms.

Two of the 10 dogs in the blood sample (20%) had coronavirus antibodies. One dog had previously exhibited respiratory symptoms.

The authors referred to previous reports of SARS-CoV-2 infection in different animal species, but did not identify risk factors or clinical features of the infection.

Dorothy Biensle, DVM, PhD, lead author of the University of Guelph, said in ESC MID news release Blood tests on animals after their owner’s recovery is the best way to assess human-to-animal transmission, as the time frame for identifying the pet’s current transmission is narrow.

Meanwhile, pet owners infected with COVID-19 need to isolate themselves, Bienzle said. “There is ample evidence from multiple studies, including us, to recommend that people infected with SARS-CoV-2 be isolated from humans and animals,” she said.

Viral RNA, same genome of cat

Secondly Investigation, Research letter published yesterday Emerging infectious disease, Hong Kong researchers test respiratory and fecal samples of 50 cats in COVID-19-infected households, or close contact with coronavirus RNA from February 11 to August 11. did.

Six of the 50 cats (12%) were positive for SARS-CoV-2 RNA by RT-PCR and had the same viral genome in one domestic cat pair. All cats were asymptomatic but had lung abnormalities similar to those of infected humans. Researchers were unable to propagate the virus in cell culture.

“Although cat-to-human transmission is theoretically possible, no evidence of this transmission has been found,” the authors said. “The timeline for cat 1 infection and the discovery of the same SARS-CoV-2 genomic sequence in humans in the same household are consistent with human-to-animal transmission. To support these findings, cats I couldn’t access the outdoors. “

Researchers called for broader serological monitoring of cats connected to COVID-19 patients to determine the spread of human-to-cat transmission.

The Hong Kong Ministry of Agriculture, Forestry and Fisheries has isolated pets from infected households and is in close contact with breeding facilities when no other care is available. Pets are isolated until they are negative on two RT-PCRs. COVID-19 infections identified in dogs as part of this test Investigation Published May 14th Nature— First published evidence of this disease in dogs.

Possibility of zoonotic infection from mink

number 3 InvestigationIt will also be announced at the ESCMID conference, which included monitoring of COVID-19 infections on 16 mink farms with more than 720,000 animals in the Netherlands. According to the author, this finding suggests that the coronavirus jumped from human to mink.

Of course, SARS-CoV-2 may have first jumped from animal to human in late 2019, causing a pandemic in Wuhan, China.

In this study, published on the preprint server bioRxiv on September 1, Dutch researchers investigating the outbreak of coronavirus in both animals and humans on mink farms tested and tested to track the source of infection. A whole genome sequence was performed. Of the 97 people living or working on the farm, 66 (67%) were diagnosed with COVID-19 by PCR or antibody testing.

The author said in ESC MID news release They believe that at least two people on the farm were infected with mink. “Unfortunately, we don’t know the total number of people infected with mink because our research can’t draw clear conclusions about the direction of most infections,” they said.

“The virus was originally introduced from humans and evolved in mink farms, reflecting the widespread circulation between minks in the first SARS-CoV-2 mink farms weeks before detection. It is thought that there is. “

Coronavirus was first detected on two mink farms in late April. Some of the farms involved in the outbreak were owned by the same person, but no epidemiological association with other farms could be confirmed.

Genomic sequencing revealed that the SARS-CoV-2 virus was the same virus found in mink and not the same virus found in COVID-19 patients living near farms. Sequences from all infected mink farms are included in one of five different disease groups and show spread across farms.

Currently, COVID-19 is widespread on farms, but despite efforts to combat it, three large clusters of unknown transmission routes have been identified.

“The population size and structure of mink farms is such that SARS-CoV-2 (after introduction) is expected to continue to be distributed,” the authors write. “Therefore, continuous monitoring and cooperation between human and animal health services is important to prevent animals from functioning as reservoirs for continuous human infection.

“Close cooperation between human and animal health departments is essential for early detection and control of SARS-CoV-2 infection,” they added in a news release.