Giant pandas are one of the world’s most endangered species. But, as we said earlier, three pandas have died from canine distemper virus, or CDV, in the past month. Another one is still in critical condition. Questions are being raised about the Shaanxi Rare Wildlife Rescue and Breeding Research Center in Xi’an, Shaanxi province, where the four infected pandas once lived.

Shanghai’s The Paper reported that the center saved eight seriously injured pandas in the wild and then put them on display in a cage. They charged 30 yuan — or about $5 — to see them during peak season, and 20 yuan in the off-season. It’s now being questioned whether it’s legal to charge for tourism purposes, and the close contact between the giant pandas and the public may have increased the chances of infection.

The Paper’s report also revealed that pandas should be sent back into the wild after they have recovered and it questioned whether the center is suitable for keeping wild animals. The center is located in a densely-populated area where stray animals may bring contagious diseases to the pandas.