After the first phase of rescue work, the top priority has shifted to the prevention of epidemics. CCTV reporter Han Bin, along with cameraman Zhong Rui, followed one of the key medical teams from the PLA to the quake-hit areas to see how they carry out this mission. As they found out, the work has been extremely challenging.

After the first phase of rescue work, the top priority has shifted to the prevention of epidemics.

A blast at Xuankou Middle School, a dangerous building in Yingxiu. This marks the start of the clearing work. After two weeks of rescue efforts, there are no more signs of life. People are buried here. And it's time for the anti-epidemic forces to play a key role.

Li Feng is asking the soldiers to change their masks everyday. He's the commanding officer for the anti-epidemic campaign in Yingxiu. Li Feng has taken part in previous anti-epidemic missions after floods and during the SARS crisis. But he says the current task in Yingxiu is the toughest he has faced.

Li Feng, senior colonel of Military Academy of Medical Sciences, said, "The current priority is to save lives, that's to say, facing this complicated situation, we must protect the environment as much as possible, by changing and controlling the situation."

Since Yingxiu sits on the upper reaches of the Mingjiang River, preventing contamination of the river further downstream has been the doctors' top priority. Water tests are carried out twice a day, checking for 13 factors including chemicals, heavy metals, poisonous germs and microbes.

Waste and rubbish have been burned to curb pollution.