The death toll from Sunday's earthquake in Yunnan province rose to nearly 600 on Wednesday as a key 72-hour period for rescue work passed.

The magnitude-6.5 quake has killed 589 people and injured more than 2,000 others.

Although the 72-hour "golden period" had passed, rescuers were still trying to find residents buried in rubble.

Deng Zhiping, an army commander, told soldiers not to abandon any opportunity to save lives. Troops will continue to be sent in if residents find and report survivors among the debris, Deng said.

But he said rescuers in rural areas of Longtoushan township, the quake epicenter, had experienced great difficulties.

Workers had to use a helicopter on Wednesday to carry an injured woman from her mountainside home to the township, as the quake had badly damaged the route to her house.

Li Zuocheng, another army commander, said rescuers had to clamber over two mountains to reach the village of Cuiping, about 15 km from the township.

Wang Cheng, a police officer helping with rescue work in rural areas, suggested that provincial authorities designate areas for helicopter landings.

"People who are seriously injured in remote villages only have helicopters to rely on," Wang said.

Major roads to the township have been kept clear and many vehicles carrying relief materials, including food and water, have been allocated to residents.

Li said that food safety, as part of epidemic prevention work, is being highlighted in shelters, adding that disease control has been extended across Ludian county.

The provincial health authority has sent more than 360 workers to improve sanitation and prevent epidemics. At least five members had been assigned by Wednesday to disinfect every village.

Lu Lin, director of the provincial disease control center, said, "The major work is to estimate infectious diseases, ensure the safety of drinking water and give medical knowledge to people."

Colds, hepatitis and diarrhea are common after disasters, so every part of the epicenter must be disinfected, Lu said.

Four disinfecting vehicles have arrived in one community in the township and soldiers have been ordered to help with the work.

Many bodies in the area are rotting and a foul smell is coming from a river in the community, a sign that epidemic prevention work is needed urgently.

The provincial health authority dropped at least 200 manual sprayers by air to help with the work.

Contact the writers at anbaijie@chinadaily.com.cn and guoanfei@chinadaily.com.cn

Cao Yin and Zheng Jinran in Beijing contributed to this story.

(China Daily 08/07/2014 page1)