A suspected outbreak at a pet store in January led to a hamster cull in Hong Kong.Credit score: Chan Lengthy Hei/Bloomberg/Getty
Pet hamsters most likely carried the Delta variant of SARS-CoV-2 into Hong Kong and sparked a human COVID-19 outbreak, in response to a genomic evaluation of viral samples from the rodents. The analysis confirms earlier fears {that a} pet store was the supply of the outbreak, which has thus far contaminated about 50 folks and led to the culling of some 2,000 hamsters throughout town.
The seek for animals harbouring coronavirus — and why it issues
Hamsters are extremely vulnerable to SARS-CoV-2 and so are a well-liked mannequin for finding out the virus. However the Hong Kong examine — posted on-line as a preprint1 and but to be peer reviewed — is the primary to point out that hamsters can grow to be contaminated exterior the laboratory, and that they will move the virus on to each different hamsters and people.
Hamsters are solely the second animal identified to have the ability to infect folks, after mink. In late 2020, small outbreaks of COVID-19 in folks in Denmark and the Netherlands had been linked to farmed mink, sparking panic and mass culls.
The most recent examine factors to the pet commerce as a route for viral unfold, says co-author Leo Poon, a virologist on the College of Hong Kong. However “to be truthful to the hamsters”, persons are nonetheless more likely to be contaminated by one another than by pets, he says.
New route for viral unfold
Nonetheless, you will need to monitor the pet commerce carefully, says Marion Koopmans, a virologist on the Erasmus College Medical Middle in Rotterdam, the Netherlands. SARS-CoV-2 might proceed to flow into in animals, evolving in surprising methods, after which spill again into folks, she warns, including that “we don’t want extra surprises with this virus”.
Hong Kong has maintained a strict zero-tolerance strategy to COVID-19, so when a 23-year-old pet-shop employee examined optimistic for Delta on 15 January, Poon says it was “a bit weird”. The final time town had seen Delta in the neighborhood was in October.
Inside days, public-health officers had swabbed greater than 100 animals on the pet store and one other 500 on the warehouse supplying it. They detected SARS-CoV-2 viral RNA or antibodies towards the virus in 15 of 28 Syrian hamsters (Mesocricetus auratus), however in not one of the dwarf hamsters, rabbits, guinea pigs, chinchillas or mice.
The researchers then analysed genomic sequences of samples collected from 12 hamsters and the primary 3 contaminated folks, together with the pet-shop employee and a customer to the store. The entire samples contained a variant of Delta that had not beforehand been detected in Hong Kong and possibly originated from the identical supply.
The staff additionally seen some range within the sequences, and concluded that the hamsters had been most likely first contaminated in November, earlier than their arrival in Hong Kong, and that the virus had been spreading undetected among the many animals, accumulating just a few single-nucleotide mutations alongside the best way.
Leaping between species
The pet-shop employee and customer had been most likely contaminated on separate events, and Poon says there might have been extra jumps. Most stunning, he says, was that even after replicating in hamsters, the virus might nonetheless “transmit between people fairly successfully”.
The warehouse imported the animals from the Netherlands, and additional evaluation of genomes uploaded to a public world database recognized their closest match in sequences collected in folks in Japanese Europe.
Did the coronavirus bounce from animals to folks twice?
Koopmans says she is satisfied by the evaluation and its conclusion that the variant was imported into Hong Kong within the animals. It will likely be essential to trace down the supply of the an infection in hamsters, she says.
However Arinjay Banerjee, a virologist on the College of Saskatchewan in Saskatoon, Canada, says the researchers can’t rule out the chance that the hamsters had been first contaminated by an individual in Hong Kong and weren’t accountable for importing the virus into the nation. “There are such a lot of folks dealing with hamsters throughout the technique of them being transported.”
Finally, he says, the danger of an infection from hamsters nonetheless appears low, however is “one thing to pay attention to”.
