Shen said a system for reporting infectious diseases will soon be established to beef up epidemic surveillance in areas hit by Saturday's magnitude-7 quake centered in Ya'an.

　　He Xiong, deputy director of the Beijing Center for Disease Control and Prevention, said epidemic prevention specialists are working in, or heading to, the quake zone.

　　He, the leader of an anti-epidemic team of about 30 experts, said the team will start working in Lushan county on Tuesday.

　　Infectious disease prevention efforts mainly target makeshift shelters, He said, usually where there is a high density of people but living conditions are poor.

　　"We'll first carry out risk assessments for the main factors, including safe and clean water and food surveillance, basic public health conditions, insects that might spread disease to humans, and waste disposal around the shelters," he said.

　　Based on the assessments, targeted measures such as routine disinfection and emergency vaccination programs will be introduced, he said.

　　Strengthened epidemic surveillance has to be performed, particularly for problems like intestinal infections and insect-borne diseases, he said.

　　The team is the second committed to epidemic prevention and control to be dispatched by the National Health and Family Planning Commission.

　　The first, comprising experts from the Academy of Military Medical Sciences, arrived in Ya'an on Sunday night.

　　In the meantime, routine disinfection work has already been performed in the affected areas, according Shen Ji, the Sichuan health chief.

　　Medicine needed

　　Residents of Lushan urgently need antibiotics to treat alimentary and respiratory infections, said emergency doctors in the county.

　　"Victims have access to only instant noodles, bread and cold water, which has led to many cases of alimentary tract infections," said Fu Xuetao, a local pharmacist. "Also, it's easy for them to catch cold, staying overnight in the tent in the rain. The cases we have discovered include cough and pneumonia."

　　Rain fell on Sunday night in the areas surrounding Lushan and Baoxing counties.

　　Tang Weige, president of the 42nd Hospital of Chengdu Military Command, which sent a medical team to the quake zone, said colds may be prevalent in the days to come.

　　"People were very nervous for the first three days after the quake, but that enhanced their immunity. Their level of immunity will drop greatly on the fourth day when they feel relaxed, and many will get colds or even fevers," he said. "That was the case in the Wenchuan earthquake five years ago."

　　The Sichuan health department has prepared medicine to treat 30,000 people for colds.

　　Rescuers are racing against time in the search for survivors. On Monday, more than 300 soldiers from Chengdu Military Command searched villages in Lushan, the epicenter of the quake.

　　Almost all houses in Hexing village were damaged, which added difficulty to carrying out rescue work, especially with the constant aftershocks.

　　"The walls of these houses are fragile and they may collapse at a touch," said Wu Luzheng, who is in charge of rescue in the village.

　　"Besides the rescue, we also help villagers move valuable property out of their houses," he said.