(CNN) -- More rain is expected Friday in northwest China's Gansu province, where the death toll from a massive mudslide continues to climb.
By Friday, the toll had risen to 1,156, with 588 still missing, state-run Xinhua news agency said.
Local residents believe that number is higher.
The downpour has been steady, impacting relief work and leading to fears there may be more mudslides.
Torrential rains triggered the mudslides Sunday.
The side of a mountain broke off in the night and tore through remote Zhouqu county, burying homes and ripping others apart. The path of the mudslide is covered in three and four stories of rock and mud.
Local health officials say the spread of disease is now a major public health concern in the county after health facilities and water resources were damaged, Xinhua reported.
A health ministry official told Xinhua that high temperatures can cause corpses and dead animals buried under the mud to decay.
Although wells have been dug up to ensure water supply, the ministry said sterilizing the water takes time.