Hong Kong (CNN) -- Swarms of aggressive hornets, in their fall mating season, are inflicting a deadly toll in a central Chinese province.
Hornets have killed 42 people and injured 1,675 people in three cities in Shaanxi province since July, according to the local government. Thirty-seven patients remain in critical or serious condition.
Over the summer and early fall, hornets have invaded schools full of children and descended upon unsuspecting farm workers in China.
One of them is Mu Conghui, a woman who was attacked in Ankang City while looking after her millet crop.
The hornets were horrifying, she told Xinhua, the Chinese state-run news agency. They hit right at my head and covered my legs. All of a sudden I was stung and I couldnt move.
Even now, my legs are covered with sting holes.
Two months, 13 dialysis treatments and 200 stitches later, Mu still remains hospitalized and unable to move her legs.
The influx of venom to the human body can cause allergic reactions and multiple organ failure leading to death. Patients like Mu have been receiving dialysis to remove the toxins from her body. In photos, patients bore deep dark craters scattered across their limbs, the size of bullet wounds.
Government authorities say these attacks are from a particularly venomous species, the worlds largest hornet, known as the Asian giant hornet or vespa mandarinia.
The giant hornet extends about 3.5 to 3.9 centimeters in length, roughly the size of a human thumb. It has an orange head with a black tooth used for burrowing, according to an animal database at the University of Michigan.
Dr. Wang Xue, director of the intensive care unit at First Affiliated Hospital of Xian Jiaotong University and an expert of the provincial hornet sting treatment guidance unit, warned in a Shaanxi government release that hornets tend to be aggressive and more active during September and Octobertheir breeding season. The hornets do not go into hibernation until December, according to local government authorities.
Local authorities have deployed thousands of police officers and locals to destroy the hives. So far, about 710 hives have been removed and at least 7 million yuan (about $1.1 million U.S.) sent to areas affected by hornets, according to a government press release.
The spate of attacks could be caused by the unusually dry weather in the area, authorities say. The arid environment makes it easier for hornets to breed. Urbanization could also be a contributing factor, as humans move into hornets habitats.
Some experts cited in Xinhua stated additional factors such as increased vegetation and a decrease in the hornets enemies, such as spiders and birds because of ecological changes.
Humans can inadvertently irritate the hornet hives, as most are tucked away in secluded places, such as tree hollows or even underground.
The provincial government has warned residents to wear long sleeves when outdoors, and not to attempt driving away the swarms or removing their hives.
Vespa mandarinia are known as formidable, carnivorous killers, found in eastern and southeastern Asia, especially in Japan.
About 30 to 50 deaths are reported each year in Japan from such attacks, according to Japanese studies. Most of the deaths are due to allergies to the venom, said Shunichi Makino, director general of the Hokkaido Research Center for Forestry and Forest Products Research Institute.
