when the virus emerged , he said . The virus is also becoming more active in Europe and Central and Western Asia , Fukuda said . Health officials this week reported an outbreak of cases in Ukraine , which now has more than 250,000 cases of influenza-like illness , with 235 patients requiring intensive care , the WHO said . Activity is picking up in East Asia , Fukuda said . Mongolia reported `` a number '' of cases over the past week , he said . `` East Asia is one of the parts of the world where seasonal influenza viruses have remained in reasonably high circulation , '' Fukuda said . `` But even in that part of the world , the pandemic virus is becoming dominant . '' More cases are being reported from a number of Caribbean countries such as Cuba and Haiti , he said . In Central America and the Southern Hemisphere , however , activity levels have dropped as those regions enter the summer season , Fukuda said . `` There are several regions in the world -- North America , Europe , Northern and Central Asia -- where we are clearly seeing
-LRB- CNN -RRB- -- The H1N1 virus has now become the dominant influenza virus around the globe , with high levels and an increase of activity in many regions , the World Health Organization said Thursday . In a weekly update , the WHO 's point person on the H1N1 virus , Dr. Keiji Fukuda , also warned the public not to treat the virus like just another flu . Like seasonal flu , H1N1 is more active in the winter than in the summer , and a majority of infected people get better on their own , Fukuda said . H1N1 also is as transmissible and infectious as seasonal flu , he said . But unusually for influenza , Fukuda said , H1N1 continues at high levels over the summer months , and many of the serious illnesses and deaths are concentrated in people younger than 65 . Seven months into the pandemic , the virus commonly known as swine flu remains at high levels and continues to increase in North America , Fukuda said . Mexico , for example , has seen more cases from September to November than they saw in the preceding months from April ,