A Japanese school in German western city of Duesseldorf has reported 30 cases of A/H1N1 flu, German authorities confirmed on Thursday, reports Xinhua.
This is the most concentrated outbreak of the flu cases so far in Germany, the most populous country in Europe.
The majority of the cases at the Japanese school in the city were detected on Wednesday evening, said Kathrin Rebbe, a spokeswoman for the health ministry in the state of North Rhine-Westphalia.
The school has closed until next week and the infected children are now in quarantine, she added.
Duesseldorf is home to a large Japanese community in Germany, the biggest economy of Europe.
Prior to the collective outbreak in the school, Germany had 86 confirmed cases of the flu, according to the Robert Koch Institute, the country's federal agency for infectious diseases.