Human SARS-CoV-2 infections from imported hamsters in Hong Kong: A first-and-only event?

On Jan. 28, 2022, a highly-respected senior research group from the University of Hong Kong posted a preprint reporting that Syrian hamsters (Mesocricetus auratus) imported from the Netherlands were the likely source of human infections with the Delta variant of SARS-CoV-2 (see italicized quotes below). It should be anticipated that potentially similar past events (unrecognized), as well as potentially similar future events, related to such hamsters will be hypothesized.

By coincidence, some of the same senior University of Hong Kong researchers were uniquely qualified to discover this recent 2022 outbreak in this species of hamsters. The reason is that they had coauthored a paper in Nature early in the pandemic (May 14, 2020) demonstrating in laboratory studies that Syrian golden hamsters (Mesocricetus auratus) were susceptible to SARS-CoV-2 infection and transmission.

The Jan. 28, 2022, manuscript by Yen et al., however, is the first time that pet hamsters of this species were reported to be infected with SARS-CoV-2, as they state below:

Over 50% of individually tested Syrian hamsters in the pet shop (8/16) and warehouse (7/12) were positive for SARS-CoV-2 infection in RT-PCR or serological tests …

SARS-CoV-2 viral genomes deduced from human and hamster cases in this incident all belong to Delta variant of concern (AY.127) that had not been circulating locally prior …

The viral genomes obtained from hamsters are phylogenetically related with some sequence heterogeneity and phylogenetic dating suggest infection in these hamsters occurred around 21 November 2021 …

Two separate transmission events to humans are documented, one leading to onward household spread …

Importation of infected hamsters was the most likely source of virus infection …

It also suggests that the pet animal trade may be a pathway that can facilitate the movement of SARS-CoV-2 across national borders.