Outbreaks of infectious diseases have not been detected in China's quake zone 15 days after a 7.0-magnitude earthquake jolted Sichuan province killing 196 people, local health authorities said.

Health authorities are exterminating pests, monitoring drinking water and preventing any potential outbreak of diseases at relocation sites, according to the health bureau in the city of Ya'an, the quake's epicenter, on Sunday.

In a high school in Ya'an, which has been transformed into a major relocation site, sterilizing fluids could be smelled, rubbish bins were placed orderly and posters about disease control were on the wall, according to a Xinhua reporter.

"We are optimistic about disease control in the quake zone," said Yuan Zhengquan, who heads a disease control team working in Ya'an.

Yuan, a public health expert with the Academy of Military Medical Sciences, said his team has been focusing on disease control in remote villages.