Dogs first discovered coronavirus SARS-CoV-2. Their infected hosts

In Hong Kong, two dogs whose owners were hospitalized with COVID-19 assays detected RNA of the coronavirus SARS-CoV-2, and antibodies to it. This is the first recorded case of transmission from man to dog. Infection in animals is asymptomatic; the second dog, which lived in the same house with one of the dogs, not infected. It is not clear whether dogs can infect humans or other canines. Article accepted for publication in the journal Nature.

There are known cases of transmission of the coronavirus SARS-CoV-2 from human to cats, ferrets and tigers. However, until now there was not a single case of infection of dogs, although their receptor ACE-2, which is necessary for the virus to get into cells, similar to human.

Scientists from Australia and China under the leadership of Malik Peiris (Malik Peiris) from the University of Hong Kong, took samples from 15 dogs whose owners have been hospitalized with COVID-19. Animals were quarantined, they were taken care of, the staff of the Department of agriculture, fisheries and conservation Hong Kong. Two dogs in the analyses by polymerase chain reaction with reverse transcription (RT-PCR) detects the RNA of the coronavirus SARS-CoV-2.

When RT-PCR enzyme shaped transcriptase builds on the matrix of RNA corresponding to the DNA sequence, and then DNA polymerase repeatedly reproduce (amplificare) this molecule. Reverse transcriptase “sees” only those RNA which are complementary sit them primer — a short nucleotide chain. Scientists choose primers that are specific for viral RNA. In the end, there DNA copies we need (viral) portion of the RNA, and after amplification they become enough to determine the presence of viral genes in the sample.

First affected dog was a 17-year-old Spitz. His mistress of 12 February 2020 the symptoms, and on 24 February confirmed COVID-19. After that, all members of the family, including the dog, were isolated. On February 26 the animal took swabs from the nose, mouth and anus, and stool sample. In this and subsequent analyses, from the nose detected the RNA of SARS-CoV-2; to select the whole virus into the culture failed because of a weak viral load. Two days after returning to the family of Spitz died. The hostess did not give permission for post-mortem, but scientists speculate that the cause of death was one of the side diseases that developed in dogs to illness of the owner.

The young German shepherd positive for SARS-CoV-2 were tests that took 18 March, a day after the owner of the dog was diagnosed with COVID-19. Viral RNA was found not only in smears from the nose and mouth, but also from the anus. The second dog, which lived in the same house, not contracted.

Both dogs for the duration of the quarantine showed no symptoms of infection. In the blood serum of dogs found antibodies to the SARS-CoV-2 (a Spitz — in the analysis of the third of March, a German shepherd — 19, 23 and 30 March); the second dog, which lived with a dog, antibody test March 30 was negative. The sequence of the viral genome, which was sequenced from both dogs and their owners, were identical in each pair of the dog owner. But between the different families of the genomes of SARS-CoV-2 was distinguishable.

The authors emphasize that the obtained data are insufficient to judge whether the virus can be transmitted from dog to another dog or back to the person. However, this probability is, therefore, necessary to isolate and test not only of people who had contact with sick COVID-19, and Pets.

A month ago we were told about the experiment, in which the coronavirus tested a range of Pets: cats, dogs, ferrets, pigs, chickens and ducks. The animals were infected with the virus and tested it, multiply it. In this study all tested animals susceptible to SARS-CoV-2 was only cats and ferrets, what these animals were able to transmit the virus to each other

Alice Bahareva

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