Dozens of Dutch tourists are spending their holiday in Macedonia in the bathroom rather than at the pool or the beach. A mysterious virus from the nearby Skopje has two-thirds of the Dutch tourists in the Izgrev Spa & Aqua Park in Ohrid stuck in their hotel rooms.

The hotel has room for about 700 guests, 332 of them are Dutch tourists who traveled through travel agency Corendon. So far only about 20 people reported to the company that they were sick. All of them were treated for diarrhea. CEO Atilay Uslu told the Telegraaf that the virus has to do with “something in the pool. But I’m not a doctor.”