A giant panda research base in northwest China's Shaanxi Province has closed panda living and entertainment area to visitors, in order to protect the endangered species from the risk of A/H1N1 flu infection.

Shaanxi Wild Animal Rescue and Research Center, one of China's four giant panda bases, stopped recruiting volunteers and made a 2,000-square-meter area off-limits to visitors last week after heavy snowfall brought sudden temperature drops and a rise in the number of A/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 monkey, takins and crested ibis.

Only the five panda carers and two vets were allowed to enter the panda living quarters, said the center's deputy chief Jin Xuelin. "For safety considerations, they have to wear masks and gloves before entering the panda houses."

The zoo workers' temperatures are taken twice a day and those with flu symptoms are also banned from approaching the animals, said Jin.

"It's still not certain whether pandas are susceptible to A/H1N1 flu, but we need to be careful," he said. "Seasonal flu cases were reported several times at the giant panda research base in Sichuan's Wolong in the past."

Shaanxi Province reported its first A/H1N1 flu death on November 20and at least 13 were critically ill with the epidemic as of Monday, the provincial health department said.

Jin said the center would open to tourists again after the flu season. "Hopefully in spring."

Before it reopened, panda enthusiasts could catch a glimpse of the bears on the center's website www.qlpanda.org, which has photos and video clips.

A visit to the center, founded in 1987, costs 35 yuan.

All the pandas at the center are unique to the Qinling Mountain Range and belong to a new, and more endangered sub-species of pandas.

Pandas were first spotted in Qinling Mountains in 1964, a century after the bears were first reported in Sichuan, home to most of China's pandas.

Compared with their peers in Sichuan, Qinling pandas are smaller in population -- approximately 300 compared with more than1,300 other pandas living elsewhere in China.

These pandas also have smaller skeletons, larger cheek teeth and traces of brown instead of the typical black-and-white for other pandas.

(Xinhua News Agency November 24, 2009)