The Ministry of Health has called for measures stepped up to be in the earthquake zone in Northwest China's Qinghai province to prevent an outbreak of marmot plague after Himalayan marmots were detected in the area.

The marmots were found in the Horse Racing Ground, a temporary settlement for quake survivors in Gyegu township of the Yushu Tibetan autonomous prefecture in Qinghai, the ministry said.

So far no outbreak of major epidemics, including the plague, has been reported, but epidemiological experts said the challenges in averting and controlling an outbreak of marmot plague in the quake-hit area were considerable.

The marmots, a type of ground squirrel indigenous to the region, have woken from hibernation, increasing the possibility of an outbreak of the fatal disease among quake survivors, the ministry said on Monday.

The plague is particularly virulent because it can be passed to other people via coughing. If left untreated, mortality rates range from 50 to 90 percent, according to the World Health Organization.

The ministry has been closely monitoring marmots' activities in a 600-hectare area in the quake zone, which has a record of plague outbreaks.

In the past five decades, Yushu has seen 20 outbreaks of human-to-human transmission of plague, the latest in 2004 claiming six lives, according to Yu Dongzheng, a researcher specializing in epidemic prevention with the Chinese Center for Disease Control and Prevention (China CDC).

To help raise public awareness, China CDC has so far delivered 80,000 bilingual disease prevention brochures in Chinese and Tibetan, and 10,000 plague prevention leaflets to the quake zone, with more on the way.

More than 3,000 people, including medical experts and monks, were trained on how to control and prevent marmot plague.

"It's necessary, as lots of quake relief workers were dispatched from non-plague areas, so they must be quickly familiarized with the disease for the sake of early detection," said Ni Daxin, an epidemiologist with China CDC in charge of epidemic risk evaluation in the quake zone.

Some locals also hunt marmots for fur and meat. "They must be warned against that," he said.

"Those developing symptoms of fever, coughing or swelling glands need to be scanned for plague," he said.

Ni also warned of other epidemic hazards in the quake zone, like rabies.

Although Yushu has reported no rabies outbreaks in recent years, many dogs are wandering the streets and some dog bites have been reported, Deng Ershou, deputy director of Qinghai CDC, told China Daily on Monday.

"Thanks to ongoing educations, most of those who were bitten have been vaccinated, which were provided free of charge at designated makeshift medical centers," he noted.

"So far no human rabies has been reported here."