XI'AN/CHENGDU, Jan. 14 -- Veterinarians are racing to treat another critically ill giant panda after a measles-like virus recently killed two pandas in captivity in northwest China's Shaanxi Province.

Results of daily medical tests on five-year-old Feng Feng showed serious heart, liver, kidney and lung damage from canine distemper virus (CDV), a highly contagious and fatal disease, according to a spokesman for the Shaanxi provincial wildlife rescue, breeding and research center.

Feng Feng tested positive for CDV on Dec. 26 and began to show neurological symptoms on Jan. 2. Experts have been conducting antiviral therapy on the animal.

Cheng Cheng and Da Bao, both eight years old and living at the center, died from CDV infection on Dec. 9 and Jan. 4 respectively, despite efforts to save them. A fourth infected panda, 14-year-old Zhu Zhu, is in stable condition.

CDV, which affects a wide variety of animals, including dogs, primates and large cats, targets the gastrointestinal and respiratory tract, as well as the spinal cord and brain.

Infected animals usually have symptoms such as high fever, eye inflammation, coughing, vomiting, diarrhea, and lethargy. The virus commonly spreads through contact with infected body fluids or contaminated food and water.

Prior to the epidemic, the center was home to 25 giant pandas. After the outbreak, the center sent its healthy pandas to nature reserves elsewhere in the province.

CDV is called the "number one killer of giant pandas." It is the second time a mass infection has broken out among giant pandas after a previous outbreak in east China's Nanjing City many years ago, according to Hu Jinchu, a panda researcher.