Hundreds of people stung in Shaanxi province by swarms of giant insects believed to have multiplied over warm summer

Twenty-eight people have died and hundreds have been injured in a wave of attacks by giant hornets in central China, according to reports.

Victims described being chased for hundreds of metres by the creatures and stung as many as 200 times.

Most of the attacks in the past three months were in remote, rural, wooded areas in southern Shaanxi, the province's China Business newspaper reported.

In the city of Ankang alone, 18 people have died from the stings, health official Zhou Yuanhong told Associated Press. People in the cities of Hanzhong and Shangluo have also been injured.

The insects' highly toxic stings can lead to anaphylactic shock and renal failure. An official from Ankang's disease control centre urged people to seek medical help if they received more than 10 stings, and warned that emergency treatment was required for those stung more than 30 times.

One woman in her 50s said she had spent almost a month in hospital and was still incontinent after receiving more than 200 stings. A man from her village died of kidney failure.

The hornet attacks are a recurring problem in the area from May to as late as November. According to Ankang police, 36 people died in the city and 715 were injured by the creatures between 2002 and 2005. But Zhou said the issue had been particularly severe this year, possibly because of weather changes.

Experts have suggested in the past that warmer temperatures in the area have led to hornets breeding more successfully, that labourers have been moving deeper into areas where they may disturb nests, and that the insects are sensitive to chemicals found in food and cosmetics.

Li Jiuzhou, deputy director of the Shaanxi Bee and Wasp Industry Association, said that hundreds or even thousands of hornets could live in a single nest. They attack humans only if disturbed, he added. But they are carnivorous and can quickly destroy bee colonies.

Ankang's fire service has removed over 300 hornet nests this summer, but experts said that the problem was unlikely to end entirely until the temperature drops.

Wang Zhengcai, an official from one of the affected villages, said authorities had warned people to be careful if they enter the woods. Local authorities have also promised to help patients pay for the treatment, because of the heavy cost for the rural poor.

The culprit appears to be the Asian giant hornet or Vespa mandarinia, which grows up to 5cm long with a 6mm sting, although the area is also home to the smaller Asian hornet, Vespa velutina nigrithorax.