This article first appeared on RTL.de.

In a hospital in Aalen in Baden-Württemberg it is not possible to operate - and that because of uninvited guests. Fruit flies have paralyzed the central operating room, five operating rooms are affected. A special company had to move in to fight the invaders, but the plague has not yet been banned. Where did the flies come from anyway?

There has been no sterile environment in the Ostalb Clinic in Aalen in the past few days. The surgical instruments have to stay where they are in five rooms, because flying visitors have made themselves comfortable in the hospital. Fruit flies of the genus Drosophila melanogaster have made themselves at home in the day room and in the corridor of the central operating theatre. Nothing has been going on there since last Saturday. Normally 25 surgeries take place here on weekdays.

This "abnormality" was noticed by the clinic staff through a control system that checks the air for purity. The central operating theater was then closed immediately and operations were cancelled. Emergencies are transferred to other clinics.

"Particularly high hygiene requirements apply in this very sensitive area of ​​the central operating room. We will not take any risks or compromises here," says CEO Prof. Ulrich Solzbach in a press release. In order to get the problem under control, a cleaning team thoroughly disinfected the rooms in the central operating room.

The insects should be identified with fog cans. Gases are designed to eliminate the fruit flies. A few flies held up well.

Ralf Mergenthaler, spokesman for Ostalb-Klinikum Aalen, was puzzled for a long time. He speculated on food left in the recreation room that might have attracted the fruit flies. It could also not be ruled out that they got to the hospital via the ventilation system.

The reason is a clogged roof drain. A few weeks ago there was water ingress on the flat roof of the operating theater building. This is said to have attracted the tormentors.

The leaking spot was thoroughly cleaned again today. Now the health department has to release the premises so that surgery can take place again. In the best case, this should be in a few days.