The new Omicron coronavirus variant kept spreading around the world on Sunday, with 13 cases found in the Netherlands and two each in Denmark and Australia.
It came even as more countries tried to seal themselves off by imposing travel restrictions.
The Dutch health minister said the 13 cases of the variant were found among passengers who were on flights from South Africa that arrived in Amsterdam on Friday.
Authorities had tested all of the more than 600 passengers on those two flights and had found 61 coronavirus cases, going on to test those for the new variant.
First discovered in South Africa, the variant has now been detected in several countries around the world from Germany to Australia to Israel.
Last week Omicron was dubbed a "variant of concern" by the World Health Organization.
It's sparked worries around the world that it could resist vaccinations and prolong the nearly two-year COVID-19 pandemic.
Omicron is potentially more contagious than previous variants, although experts don't know yet if it will cause more or less severe COVID-19 compared to other strains.
However, the chair of the South African medical association, Angelique Coetzee (cutziah), said in her experience, its symptoms were mild. (edit 7008)
"Currently there is no reason for panicking as we don't see severely ill patients... It might change going forward, but the hype that's being created in the media worldwide does not correlate with the clinical picture."
Countries have imposed a wave of travel bans or curbs on southern Africa to try to stem the spread.