Flu activity rises across Northern Hemisphere

The World Health Organization recently said that many countries in the Northern Hemisphere, from North America to Asia, are experiencing rising influenza activity.

Meanwhile, the number of cases in the rest of the world has waned. The WHO's most recent biweekly update reported a drop in actual virus detections, but attributed it to the holiday season occurring in many countries. Nonetheless, most Northern Hemisphere countries with temperate regions are reporting increased flu activity, according to CIDRAP News.

Influenza activity in the United States continues to increase, and while Influenza A/H3N2 viruses predominated in both Canada and the United States, influenza B was more common in the United States.

In Canada, the consultation rate for influenza-like illness increased to 6.6 percent, up from four percent two weeks ago. Canada also reported 127 new outbreaks in the last two weeks, up from 22 in the last report.

Europe's virologic pattern contrasts dramatically with North America's. 2009 H1N1 (pH1N1) viruses made up 72 percent of type A isolates over the last two weeks, while approximately 98 percent of recent US and Canadian type A isolates were H3N2, CIDRAP News reports.

In Asia, flu levels are much lower, but they have increased over the last five weeks. Chinese public health officials recently announced the beginning of flu season. South Korea and Japan both report low activity with some small increase.