Questions have been raised about the Shaanxi Rare Wildlife Rescue and Breeding Research Center in Xi'an, Shaanxi province, which has been earning money by displaying rescued pandas - some of which later became sick and died.

The Paper reported on Thursday that the center saved eight seriously injured pandas in the wild and then put them on display in a cage at the center. They charged ticket prices of 30 yuan ($4.80) in peak season and 20 yuan in the off-season.

The report said that the pandas should be sent back to the wild after they recovered and questioned whether the center is suitable for keeping wild animals.

An 8-year-old female panda at the center named Cheng Cheng was diagnosed on Dec 6 with distemper and died on Dec 9. From Dec 24 to 30, another three pandas in the center were diagnosed with the virus, according to Han Xueli, director of the center's general office.

Distemper is a highly contagious virus that mainly infects canines and felines. The mortality rate can be up to 80 percent.

On Jan 4, an 8-year-old female panda named Da Bao, one of the three diagnosed pandas, died of the disease after days of treatment.

Another of the three pandas was in critical condition and the other was in stable condition after treatment by 30 experts from around the country, Han said on Thursday.

Han confirmed that the center kept 25 pandas before the epidemic, eight of which - including Cheng Cheng and Da Bao - were rescued by the center from the wild after they were seriously injured.

But Han said that the rescued pandas were treated and were to be sent back into the wild after they recovered.

malie@chinadaily.com.cn