Authorities will cull some 2,000 hamsters and other small animals because of an untraceable outbreak of the Covid-19 Delta variant linked to a Causeway Bay pet shop, health officials said on Tuesday, adding that they “cannot rule out the possibility” of animal-to-human transmission despite a lack of empirical evidence internationally.
Speaking during a coronavirus press briefing on Tuesday, Leung Siu-fai, the director of the Agriculture, Fisheries and Conservation Department (AFCD), told reporters that two shipments of hamsters imported from the Netherlands on December 22 and January 7 were suspected to be carrying Covid-19, and could be related to an untraceable Delta outbreak.
A 23-year-old woman who worked at the Little Boss pet shop in Causeway Bay tested preliminary positive for the virus on Sunday and was confirmed to be carrying the Delta variant the following day.
Chuang Shuk-kwan, head of the Communicable Disease Branch of the Centre for Health Protection (CHP) said during the same briefing that a 67-year-old woman, who had visited the pet store on January 8, was also infected.
She had visited Little Boss with her daughter to replace the cage and get food for a hamster they had bought four days earlier. Chuang said the two customers had spent 10 or so minutes in the store and had chatted with the shop staff at a distance, all while wearing masks.
The daughter has not developed any symptoms but the husband of the patient tested preliminary positive. Remaining family members have been sent to quarantine.
The Controller of the CHP, Edwin Tsui, said authorities saw two possible sources for these infections: that the virus spread from the pet shop employee to the customer, which is “the most common method of Covid-19 transmission”; or that the humans might have been infected by animals.
Leung said the AFCD had tested 125 samples from 78 animals at the Little Boss branch in Causeway Bay and 11 samples had tested positive, all of which were hamsters.
The AFCD and CHP also collected 511 samples from a warehouse at Tai Po where the pet shop, which has 14 branches under the franchise, stored the hamsters and other small animals, such as chinchillas, guinea pigs and rabbits. Leung said the testing was still underway but they have detected multiple positive results from environmental samples, like on animal cages.
Leung announced that approximately 1,000 animals collected from the concerned store and storage unit will be euthanised after further Covid-19 testing. As environment samples had seen positive results, there was still a risk keeping the animals there, despite their individual test results, he said.
The AFCD will also round up all hamsters currently for sale in pet shops in the city for testing and euthanasia. Leung estimated that 1,000 hamsters will be collected from around 34 sellers in Hong Kong.
Leung added that after consulting experts, the AFCD believed the risk of transmission from the two shipments of hamsters since December 22 was relatively high. “We strongly advise that if citizens bought hamsters from pet shops in Hong Kong on December 22, 2020, or later, they should hand them over to the AFCD for mercy handling,” Leung said.
According to Thomas Sit, the AFCD’s assistant director who oversees inspection and quarantine, the decision to euthanise the animals was made out of “public health concerns” and “with caution.”
When reporters questioned the scientific basis behind the decision to cull more than 2000 animals, Sit said there were studies showing that hamsters can be infected with Covid-19 and are able to spread the disease to other hamsters.
However, Sit said there was no evidence of Covid-19 infection among hamsters outside of a laboratory setting. “According to my knowledge and the information I have, this case will be the first, the first time in the world,” he said.
The Netherlands has not recorded any Covid-19 infections in animals in the past 12 months, Sit said, as they were required to report immediately to the World Organisation for Animal Health if any cases were found.
On Tuesday, the CHP reported 18 new confirmed cases, of which 11 were locally infected, and more than 10 preliminary positive cases.
As of Tuesday, the total number of Covid-19 cases in Hong Kong was 13,066, while the death toll stood at 213.