Students wearing masks attend a class at the National Autonomous University of Mexico (NAUM) in the Mexico City May 7, 2009. [Xinhua/David De la Paz]

Countries around the world are continuing to take preventive measures to try and keep the outbreak of A/H1N1 influenza at bay.

Mexico late Wednesday lowered its alert level for the flu in Mexico City from orange to yellow, which indicates medium risk

All places of business -- including sports arenas, dance halls, movie theaters and restaurants -- were allowed to reopen Thursday after a government-ordered shutdown that began last week.

The government took the measure as the epidemic remained stable in the capital city, the region hit hardest by the deadly new virus outbreak.

A student wearing a mask browses the bookshelf at the National Autonomous University of Mexico (NAUM) in the Mexico City May 7, 2009. [Xinhua Photo]

However, Health Minister Jose Angel Cordova Villalobos stressed the importance of remaining vigilant against the virus even though the epidemic appears to be waning.

He said Mexico's preventive measures have been actually equal to those prescribed by the highest alert level of the World Health Organization.

Meanwhile, in the American state of Illinois, the number of confirmed cases of A/H1N1 flu surged to 225, the Illinois Public Health Department said Wednesday.

According to department officials, the dramatic climb in the number of cases was attributed to the fact that state labs were no longer backlogged with tests.

Chicago remains the epicenter of the flu outbreak in Illinois, with 93 confirmed cases.

ASEAN nations, China and Japan began a special two-day health ministers' meeting in Bangkok on Thursday to coordinate efforts against the epidemic.

Officials from the U.S. Centers for Disease Control and Prevention via video conferencing briefed participants on their experiences in dealing with the outbreak.

South Korea on Thursday confirmed a third case of A/H1N1 flu. The patient's symptoms have already disappeared and he was expected to leave a hospital later in the day. Health authorities confirmed that all people who had close contact with the patient had been checked and no suspected cases were found.

Meanwhile, the Mongolian General Authority for Emergency Management cancelled the quarantine of 104 of 109 people who had been on a flight Wednesday from Russia to Mongolia.

Five passenger who had close contact with the suspected patients will remain in quarantine.

No case of A/H1N1 flu has been reported in Mongolia but the Health Ministry has advised citizens to avoid public places and be more careful of personal sanitation.

African countries are also on vigilance of the flu. Tanzania has set up checkpoints at major air, marine and land access locations and has dispatched doctors to monitor visitors.

(Xinhua News Agency May 8, 2009)