A giant panda research base in Shaanxi province has closed the panda living and entertainment areas to visitors to protect the endangered species from the risk of H1N1 flu infection.

The Shaanxi Wild Animal Rescue and Research Center, one of the country's four giant panda bases, stopped recruiting volunteers and made a 2,000-sq-m area off-limits to visitors last week after a heavy snowfall brought sudden temperature drops and a rise in the number of H1N1 flu patients, said Wang Gang, a zoo worker at the center.

The center, located in Zhouzhi county at the foot of the Qinling mountain range, is home to 21 giant pandas, including three cubs born this year, and other species including golden monkeys, takins and crested ibis.