Photo taken on Sept 15, 2016 shows giant panda cub Hua Sheng plays with her mother Guo Guo at the Shanghai base of the Chinese Giant Panda Protection and Research Center in Shanghai.[Photo/Xinhua]

A Shanghai zoo has become the target of public anger after the deaths of two of its pandas.

According to a Sina Weibo post by the Shanghai Wild Animal Park on Jan 19, a 21-year-old panda and one of her female cubs had died of acute pancreatitis and intestinal complications respectively in December.

The post has since attracted thousands of comments from netizens, many of whom are questioning why the zoo took close to 20 days to inform the public of the incident.

In its post, the Shanghai Wild Animal Park said that the adult panda Guoguo started to develop symptoms including fever, vomit, diarrhea and abdominal pain on Dec 19. Medical experts had quickly isolated her before administering a series of tests, including B-ultrasound and CT examinations. However, they failed to find the cause of the problem.

Although Guoguo was given anti-infection and anti-viral treatments, the panda died on the morning of Dec 26. The autopsy later revealed that her death was caused by acute pancreatitis and multiple organ failure.

Her 6-month-old cub Huasheng, which means "peanut" in Chinese, developed symptoms of vomit and slight bellyache and was excreting intestinal mucus on Dec 23. On Dec 29, a CT examination discovered that the cub, which weighed about 10 kilograms, was suffering from severe intestinal twist.

The medical team immediately carried out a surgery to cut 80 centimeters of necrotic intestines and performed a blood infusion but failed to rectify the situation. The cub died on Dec 31.

The wildlife park said it had informed the Giant Panda Protection and Research Center of China about the conditions of the two pandas. It added that two veterinarians and one breeder from the center, as well as three zookeepers and other working staff, were involved in the diagnosis and treatment of the animals.

In addition, the zoo had also reached out to a number of experts, including those from the animal disease control and prevention center at the Children's Hospital of Fudan University, to help with the problem.

This is not the first time that the zoo's pandas have died, netizens said. They added that two other pandas died at the park a few years ago.

A Weibo user called "biubiu-AU" commented that the truth behind these incidents has been covered up and that the zoo should not be fit to be called a breeding center for giant pandas.

Other Weibo users expressed their condolences.

"It was such a grand event when these pandas came to the zoo. But now that they're gone, it has been such a hush affair. I hope Huasheng and her mother will rest in peace," said another netizen.

Pan Yixuan contributed to this story.