(AP) H1N1 flu is running wild in the Southern Hemisphere and is spreading rapidly through Europe. The virus is even showing signs of rebounding in Mexico.

World Health Organization Director-General Margaret Chan and health ministers from around the globe huddled Thursday in Cancun for a two-day summit to design strategies for battling the pandemic. Nations attending include the United States, Canada, China, Britain and Brazil.

"As we see today, with well over 100 countries reporting cases, once a fully fit pandemic virus emerges, its further international spread is unstoppable," Chan said during opening remarks.

Mexican officials wanted the meeting held in the Caribbean resort city of Cancun — where tourism has plunged — to highlight the country's success in controlling its epidemic with a five-day national shutdown of schools and businesses in May.

But Mexico is starting to see an increase in H1N1 flu cases in isolated areas. In southern Chiapas state and the state of Yucatan — adjacent to Quintana Roo state, where Cancun is located — cases have jumped more than 50 percent in a worrying sign that the country may see a resurgence, especially when its winter flu season begins in November.

In the space of a week ending Tuesday, the number of cases in Yucatan state jumped from 683 to 1,362, and in Chiapas from 492 to 1,079, Mexico's Health Department said. During the same week, Quintana Roo reported 102 new cases.

Yucatan and Chiapas officials blamed the spike on outbreaks in schools, which they closed a few weeks early for summer break.

"Unfortunately we let our guard down, especially after classes started, and the outbreak is unstoppable," Yucatan Health Secretary Alvaro Quijano told local news media.

Mexico has confirmed a total of 10,687 cases to date, including 119 deaths.

Source: Associated Press