People warned about severe heat wave

Health authorities in many Chinese cities warned residents not to work long hours outdoors to avoid heatstroke as several people have died in the furnace-like weather sweeping across the country, particularly in the Yangtze River Basin.

More than 90 Chinese cities issued red alerts on Wednesday for temperatures that are expected to reach 40 C and above in the coming 24 hours.

As of Wednesday noon, cases of siriasis－the most severe form of heatstroke－had been reported in five provincial-level regions across the country, such as Jiangsu, Zhejiang and Sichuan, and at least two people have died so far.

Yu Wenkui, director of the department of critical care medicine at Nanjing Drum Tower Hospital, said human cells will not function if a person is exposed to high temperatures for a long time, and this could cause multiple organ failure.

"Awareness in preventing siriasis is very important, especially for infants, the elderly and some outdoor workers," said Yu. "We suggest people avoid exposure to high temperatures and take a rest and drink water in cool places every 30 to 40 minutes."

"Tools to block sun rays should be prepared if you have to go outdoors," he added. "More vitamin C and water should also be taken to boost the body's vitality."

The hashtag #Heatstroke was trending on social media platform Weibo, with more than 2 million views so far. The heat index of most cities in Jiangsu province reached 42 to 48 C on Wednesday, according to the Jiangsu Meteorological Center.

The core temperatures of people hit by siriasis surges above 40 C, damaging the central nervous system and causing problems in several organs, the Nanjing Emergency Center said.

A decoration worker surnamed Zhang, was Nanjing's first diagnosed siriasis patient. The 37-year-old felt dizzy and vomited several times after working for four hours under the searing sun. His temperature rose to 39.9 C, his blood pressure dropped to 78/56－the normal level is around 120/80－and he was sent to a hospital.

Nanjing, capital of Jiangsu province, issued its first red alert for heat in five years on Tuesday, with its temperature rising above 39.2 C, the highest since July 1961. Its Lukou residential community experienced a record-high temperature of 42.6 C, the city's meteorological station said.

Hospitals in Wenzhou, Zhejiang province, received nine siriasis patients as of Wednesday. The neighboring city of Lishui reported at least three cases in a week, and one of those patients lost consciousness and developed a temperature of 42.5 C. The 70-year-old woman suffered from multiple organ failure and is still undergoing treatment.

West China Hospital in Sichuan province received three people diagnosed with siriasis on Sunday. One patient suffered from organ failure, respiratory problems and cardiac arrest before being pronounced dead.

Temperatures have been constantly rising in Shanghai since July 5. The current heat wave, which has also plagued much of the country, is in its ninth day.

As of Wednesday morning, cities in Zhejiang have issued 49 red alerts for heat, covering two-thirds of the province's total area. The scorching heat in some areas of Central China's Henan province recently rose to 41 C.

Lin Shujuan and Guo Jun contributed to this story.