No Sustained Spread of Swine Flu Globally

The World Health Organization announced an increase in the number of confirmed cases of swine flu on Saturday, but said there was no evidence of sustained spread in communities outside North America, which would fit the definition of a pandemic.

“At the present time, I would still propose that a pandemic is imminent because we are seeing transmission to other countries,” Dr. Michael J. Ryan, the director of the World Health Organization global alert and response team, said in a teleconference from Geneva. “We have to expect that phase 6 will be reached. We have to hope that it is not.”

Phase 6, the highest level in the organization’s health alert system, is a pandemic. But Dr. Ryan emphasized that the word pandemic describes the geographic spread of a disease, not its severity. There can be a pandemic of a mild disease. The current level, phase 5, means that the disease is spreading in communities — not just within households or in returning travelers — in two countries in one of the World Health Organization’s six regions, in this case the United States and Mexico. To move up to phase 6, community spread would have to occur in at least one other country in another region.