The researchers found that the delta type of coronavirus entered Hong Kong via domestic hamsters. Genetic analysis of viral samples from rodents confirmed that some of these animals, which were in a pet store, were responsible for the spread of the SARS-CoV-2 strain and, therefore, for the outbreak of the disease in humans with 50. infected and slaughtered about 2,000 hamsters at the site.
The most popular model for studying viruses in the laboratory, hamsters are highly susceptible to infection with SARS-CoV-2. However, the Hong Kong study, which was published online and has not yet been peer-reviewed, is the first to show that rodents can become infected outside the laboratory and pass the virus on to other hamsters and humans. In addition, minks also have this ability to transmit the virus to humans. In late 2020, for example, these animals spread Covid-19 in Denmark and the Netherlands, causing panic and mass slaughter of animals.
“A recent survey points to the pet trade as a route for the virus to spread,” says Liu Bun, a virologist at the University of Hong Kong and co-author of the study. “But to be fair to hamsters, people are still more likely to infect each other from pets.”
According to Marion Koopmans, a virologist at Erasmus University Medical Center in Rotterdam, the Netherlands, it is still important to monitor the pet trade. “SARS-CoV-2 can continue to spread in animals, develop in unexpected ways and then return to humans,” the doctor warns. “We don’t need any more surprises with this virus.”
Hong Kong has maintained a strict zero-tolerance approach to Covid-19, so they thought it odd that a pet store employee tested positive for Delta on January 15. For this reason, public health officials have collected more than 100 animals from the pet store and another 500 animals from the warehouse that supplied them. Among them, they detected SARS-CoV-2 viral RNA or antibodies to the virus in 15 out of 28 Syrian hamsters (Mesocricetus auratus), but none were found in dwarf hamsters, rabbits, guinea pigs, chinchillas or mice.
The researchers then analyzed the genetic sequences of samples taken from 12 hamsters and the first 3 infected people, including a pet store employee and a visitor. They all contain a delta variant which, until then, had not previously been discovered in Hong Kong and likely originated from the same source.
The team also noted that there was some diversity in the sequences and concluded that the hamsters were most likely infected for the first time in November, before they reached Hong Kong, and that the virus was spreading undetected among the animals, accumulating some mutations as they walked. Along the way. According to Boone, the pet store employee and visitor have likely been infected on two separate occasions. “The most surprising thing is that even after hamsters breed, the virus can still be transmitted between humans very effectively,” he said.
The rodents were imported from the Netherlands, and further analyzes of the genome, uploaded to a global public database, identified their closest match in sequences collected from people in Eastern Europe. With this finding, Marion said she is convinced that the alternative has been imported into Hong Kong in animals, but Arinjay Banerjee, a virologist at the University of Saskatchewan in Canada, says the researchers cannot rule out the possibility that hamsters were infected for the first time. once by a person in Hong Kong and you will not be responsible for importing the virus. “There are a lot of people who handle hamsters during transport, but although the risk of infection from these animals appears to be low, it is something you should be aware of.”