Taiwan on Friday said it was investigating whether a mouse bite may have been responsible for a worker at a high-security laboratory testing positive for the coronavirus, the island's first local infection in weeks.
Health officials are scrambling to work out how a female employee at Academia Sinica, Taiwan's top research institute, contracted the virus last month.
Thanks to largely closed borders and strict quarantines, Taiwan has managed to stay comparatively coronavirus-free, including defeating a major local outbreak earlier in this year that began with pilots.
Health officials have confirmed that the positive-testing lab worker had been bitten twice by mice that had been infected with the coronavirus.
But they said they were still trying to work out if that was the cause of the infection or if it was picked up elsewhere in the lab.
"Whether it is from the workplace or community, we believe the possibility of infection from the workplace is higher because we have zero confirmed infections in the community," health minister Chen Shih-chung told reporters.
"As for inside the workplace, whether it is in the office or laboratory, we determined the laboratory has a higher risk. But whether the infection is from the (mouse) bite or the environment, we need to investigate further," he added.
The lab worker had no recent travel history and has been double vaccinated with Moderna. The Academia Sinica lab has the second highest bio-safety security level.
The last confirmed local case in Taiwan was November 5. Nearly 100 close contacts of the lab worker have been traced and placed in quarantine.
Taiwan won global praise early on in the pandemic for the speed with which it sounded the alarm over the emerging deadly disease and managed to stamp it out locally.
It has recorded just over 14,500 domestic cases and 848 deaths, the vast majority during the outbreak earlier this year that was quashed.