No major epidemic had been reported in the quake zones since May 12 when the 8.0-magnitude earthquake struck southwestern China's Sichuan Province, but disease prevention still posed a major challenge, the health ministry said?on Tuesday.

"The quake zones cover a huge area of land with limited access for transportation. The possible overflow of barrier lakes formed after the earthquake could also undermine the progress of disease prevention work," said Mao Qun'an, Ministry of Health (MOH) spokesman.

These threats were amplified by the dense assembly of quake survivors, he said.

Mao said the health ministry had intensified its monitoring and report of infectious diseases in the quake zones, and had sped up emergency inoculation of people susceptible to infectious diseases to help prevent infections such as hepatitis A and encephalitis B.

Health workers had also been dispatched to quake zones to ensure the safety of drinking water and food for the quake survivors.

So far, the number of medical staff sent by the MOH to the quake zones to provide medical treatment and help with disease prevention had topped 10,000, Mao said.

(Xinhua News Agency June 11, 2008)