Don’t blame it on the sunshine. Don’t blame it on the moonlight. Don’t blame it on good times. Blame it on the yodel. Channel News Asia reports that a yodeling event in the rural Schwyz canton is believed to have made one of Switzerland’s cantons a new coronavirus hotspot.

Over 600 people attended the Swiss yodeling concert in late September, and although audience members were asked to maintain proper social distancing, masks were not required. Since then, there has been an explosion of cases in the region, from 500 in mid-September to over 1200. On Wednesday, 94 people tested positive, twice as many as the day before.

“There’s an extremely high rate of positive tests. We’ve gone from 30 to 50 per cent,” says Franziska Foellmi, chief of the overloaded cantonal hospital. “It’s time we reacted,” chief doctor Reto Nueesch added in a post online. “The explosion in the number of cases in Schwyz is one of the worst in all of Europe.”

“We can’t do anything about what happened with this yodeling group. We found out nine days after the performances that several people from the group were infected,” says Beat Hegner, who organized the concert. In response, local authorities have increased restrictions, making masks compulsory at all events with over 50 people and whenever proper distancing can’t be maintained.