In front of Bird's Nest, the National Stadium, fully-armed workers launched a new war on Friday against the capital's rats, flies, mosquitoes and cockroaches.
Such pests were dubbed the "Four Harms" in 1950s by late Chairman Mao Zedong, and later turned into a long-term national campaign to enhance public awareness of disease prevention.
The disparity between the strength of the two sides was apparent as a spray machine of the latest technology blasted a piece of grassland with tiny fog tablets, two or three of which could trap mosquitoes and flies immediately after contact.
Liu Zejun, Beijing Patriotic Sanitation Movement Committee office director, said the machine could spray the pest-killing fog over an area of 12 square km each hour.
"The spray uses water as a solvent which does no harm to plants. The killing effect can last three days to a week."
On Friday, the country launched a new drive aiming to eradicate the larva of vermin pests prior to the their appearance en masse. Sun Xianli, the committee director, said the activity was an important one before the August Games.
The exercise covered the whole city, especially Olympic venues, training facilities and areas surrounding them within a 2,000-meter radius.
Zeng Xiaofan, a Beijing Center for Disease Control and Prevention official, said mosquitoes would get no closer than two km to the areas adjacent to the Olympic venues and fields after the mass killing.
"Mosquitoes can affect athletes' performance and disturb their rest."
Workers also put a foreign-brand pesticide, called "Anbei" in translated Chinese, in pools and waterways surrounding stadiums. It was recommended by the World Health Organization (WHO).
It could immediately kill mosquito larva bred in water and was safe to both fish and humans. The effect could last 15 to 20 days.
Zeng said the humid environment, affecting both the water and grass, in the public area surrounding the stadium was suitable for pests to live.
"The stadium was built on a previously-deserted place or farmland, which could breed pests more easily than age-old residential areas."
Geng Yanling, an official in charge of the environment and landscape of the Olympic Park, said the water area of 180,000 square meters and greenbelt of 500,000 square meters and sewers within the Olympic Park, adjacent to the Bird's Nest and the Water Cube, the National Swimming Center, would receive a large scale pests extermination.
The Four Harms can spread diseases such as malaria and plague and the West Nile Virus. Zeng said Beijing's major mosquito type was different from that which caused the West Nile Virus outbreak in the United States in 1999, though they were both culicine mosquitoes.
"Mosquito diseases are few in Beijing. So far, we have not found any West Nile Virus in Beijing's mosquitoes, according to monitoring results. Most worries come from annoyance and sting from the pesky insects."
The government has made a control plan of the Four Harms. Olympic stadiums and fields have to meet the highest standards in pests control. The Beijing CDC Center has employed special pest clean-up companies, ranked class-A in an official certification, for pest-killing in the venues.
One of the Four Harms, rats, was a headache for the Olympic host as their chewing of cable lines in venues had resulted in massive power failures over the Games' history. Rat's teeth, which grow all the time, are hard enough to destroy building materials.
But Zeng was not worried about that, saying time-old remedies such as using rodenticide proved effective.
He said a German-made rodenticide was popular with Chinese CDC workers. The rat extermination drug was added into a bitterness agent and a means that could prompt vomiting.
"If a man mistakenly takes it, the drug can be spit out upon the effect of the agent. It's safe to people and the environment," Zeng said, adding rats die immediately after taking it even in 2008 -- the Year of the Rat.
The CDC has conducted various tests on rodenticides and pesticides. Zeng said the ultimate product should be environment-friendly, efficient and non-poisonous.
It also set up a "citywide surveillance network," consisting of 360 monitoring stations. It has evaluated the outcome in preventing and controlling outbreaks of pests.
A pest-control expert since 1985, Zeng said people's awareness in preventing pest-related diseases was greatly improved compared with 20 years ago.
The city's CDC has spent 10 million yuan (1.4 million U.S. dollars) on relevant facilities, such as GPS monitoring instruments, Zeng said, adding laboratories and spray facilities were most advanced which enabled researchers to observe pest's drug-resistance via a gene chip during molecule studies.
He said he hoped the Olympic Games could boost the city's disease prevention level. "In Mao's era, we merely mobilized the masses to kill harms. But now we use a more scientific way; pest control has developed into a specialty."
Zeng's team was mainly in charge of Olympic constructions. As for the vast urban area, a massive "patriotic sanitation movement" was underway.
The Beijing Patriotic Sanitation Movement Committee on Thursday sent 3 million cell phone messages to residents, calling on every family to move to clean trashes and kill baneful insects. The committee handed out 450,000 promotion papers and 40 tonnes of pesticides.
"A unified action is necessary as cockroaches cannot be exterminated effectively if a neighbor was not willing to cooperate," a sanitation official, surnamed Zhang, said in the eastern Chaoyang District, an area which contained 25 of the city's 31 Olympic venues.
Zhang said cockroaches could easily run to other corners of a building so the entire building should move to kill.
"Since SARS broke out in 2003, people have begun to pay attention to public health. Some southern cities began to clean up streets and kill masked civets and harmful pests."
In the 1950s, Chairman Mao launched the Four Harms Eradication campaign to get rid of pests, which originally were rats, flies, mosquitoes and sparrows. In the absence of sparrows, locusts consumed many crops, which later became disastrous.
Mao instructed in 1960 that sparrows should not be included in the kill list, which, instead, changed one of the four harms to bedbugs.
Another war against the "New Four Harms" was also in its peak in the city now, targeting spitting, swearing, queue-jumping and smoking in public places.