Americans are not the only ones under siege by influenza. The flu is now widespread in at least 10 European countries, and a growing number are reporting an increase in cases.

At least 16 European countries are reporting increasing flu activity, with much of it in the northwestern part of the Continent, according to the latest weekly surveillance report from the European Center for Disease Prevention and Control in Stockholm.

Norway appears to be hardest hit. So far it is the only nation on the Continent reporting “high intensity” flu transmission. As of this week, about a dozen other countries, including France, Germany and Ireland, were experiencing more moderate levels, up from four in the last week of 2012, the center said.

As in the United States, the flu arrived early in Europe. But experts there say that although activity is increasing, they do not expect the flu season overall to be much worse than normal.