Exterminating rodents overnight and attracting mosquitoes in midsummer, revealing the secrets of vector prevention and control in Tiananmen area during the centennial celebration of the founding of the Communist Party of China. The
release of rodenticides lifted more than 4,200 manhole covers
In June this year, Zhang Yong (first from right) inspected the mosquito traps near Tiananmen Square with his colleagues.
Photo courtesy of the interviewee
On June 22, disease control personnel carried out rodent control in the Tiananmen area.
Photo courtesy of the interviewee
On the same day the tourists dispersed in the Anmen area, and night fell, a group of special security personnel began to enter the venue, counted how many flies got in the cage, and even opened the manhole cover.
In February of this year, the prevention and control of vector organisms in the Tiananmen area has begun. After a series of monitoring and prevention, the vector density in this core area reached the lowest level on the eve of the Party's Centennial Conference.
On July 3, a reporter from the Beijing News talked to Zhang Yong, deputy director of the Beijing Municipal Center for Disease Control and Prevention of Disinfection and Pest Control, and revealed the security work behind the celebration of the centennial of the party.
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In July, we will kill mosquitoes to catch up with the peak of mosquitoes
Beijing News: Tell us about the security work you are responsible for this time.
Zhang Yong: Our office is mainly responsible for the control of disease vectors, that is, the prevention and control of mosquitoes, flies, cockroaches, and mice, including Tiananmen Square and the surrounding Zhongshan Park, Working People's Cultural Palace, Changpu River Park and other areas.
In February of this year, we formulated a safeguard plan. In April, we conducted a vector biological hazard risk assessment. After that, we conducted multiple monitoring and guidance and control to ensure that the celebration activities were not affected by vector organisms.
Beijing News: These are relatively common creatures in daily life. Why do they attach so much importance to prevention and control?
Zhang Yong: The prevention and control of disease vectors is an important part of guaranteeing large-scale activities, and its necessity mainly involves several aspects.
The first is the health of the population. We have to consider the risk of infectious diseases that large crowds may face.
Mosquito-borne infectious diseases have been widespread worldwide in recent years. Dengue fever and Zika virus disease are all mosquito-borne infectious diseases, including the first cases of yellow fever and Rift Valley fever in Asia discovered in Beijing in recent years.
The epidemic Japanese encephalitis in Beijing is also transmitted by mosquitoes, and it is more common in summer and autumn.
If a mosquito carrying the corresponding virus bites a person, the person may be infected with disease.
Second is the issue of the operation of the conference.
Large-scale activities require a lot of electrical equipment, and often a lot of cables and wires are temporarily laid.
Rats have the habit of grinding their teeth. They often live in underground tube wells and are prone to bite the cables. The resulting accidents such as power outages and fires have occurred before. This risk needs to be considered.
In addition, if the density of mosquitoes is too high, it will bite and harass the audience, cast and crew, and other staff present. Too many flies will also affect the environment of the area.
Therefore, we need to intervene in advance to ensure that similar situations do not occur that day.
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Carbon dioxide mosquito trap for mosquito killer
Beijing News: Is there any difference between the guarantee for this event and the guarantee for previous large-scale events?
Zhang Yong: It's really different.
In previous years, the Tiananmen area was mainly guaranteed for National Day. The time was October, and mosquitoes and flies were no longer at their peak.
This year’s celebration of the centennial of the founding of the party was held on July 1st, which is equivalent to midsummer. Monitoring data for decades in Beijing shows that the most mosquitoes in Beijing are in mid-to-late July. July 1st is the time when the mosquito density is high, so it will be difficult. bigger.
The Beijing News: How to carry out the work?
Zhang Yong: On the one hand it is monitoring, on the other hand it is prevention.
Beginning in late May this year, the Tiananmen area has carried out 4 large-scale vector monitoring tasks, once every 10 days, with the purpose of finding out the density of vector organisms in this area, including mosquitoes, flies, mice, and cockroaches.
Different organisms have different monitoring methods.
For mosquitoes, we use carbon dioxide mosquito traps, and Beijing is also the only city in the country that uses such mosquito traps on a large scale.
As you all know, carbon dioxide is an important factor in attracting mosquitoes. This device emits carbon dioxide gas quantitatively, which is equivalent to the amount of carbon dioxide exhaled by an adult. It can attract mosquitoes accurately and sensitively. Unlike attracting mosquitoes, it may attract moths, etc. Other insects; fly traps for flies, sticky ratboards for rodents, sticky paper for cockroaches, etc.
After monitoring, corresponding prevention and control will be carried out. For example, on June 22, under the unified deployment of the Municipal Health Commission, we instructed professional companies to carry out a comprehensive and unified rodent control in the Tiananmen area.
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The amount of rat poison is increased by 3-5 times than usual
The Beijing News: Is it easy for rats to hide in the underground and move away?
Zhang Yong: Deratization is still very difficult.
Generally, rats move in underground tube wells, but the role and environment of each tube well are different.
Some are drainage and sewage, some are telecommunications, communications, some pipe wells are relatively dry, some are damp, and some are very deep.
The rodenticides we are going to administer cannot be exposed to water, so we must administer them one by one according to the actual situation.
Dry tube wells can be used to put rodent poison directly. If there is water, they must be pierced and tied, and hung in a place where there is no water for rats to eat.
Underground tube wells generally have a higher rodent density. We use saturated dosing, which increases the dose by 3-5 times compared to usual to ensure that it can be maintained for a long time.
Beijing News: What is the most difficult situation?
Zhang Yong: Some tube wells are densely packed and difficult to run; some only have dry sides; some tube wells are very deep, more than ten meters in length.
Time is tight, we can't go down, we can only use a flashlight to investigate the situation, or if we encounter a dry tube well, the security personnel will go down, and we will understand the situation through communication.
The workload that day was also very heavy, starting from 7:30 in the evening until two or three in the morning, 32 groups, each with 6-7 people, put rodenticides into more than 4,200 tube wells.
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Staggered work "human flesh" mosquito trap
Beijing News: When does your work generally start?
Zhang Yong: Every time it starts in the afternoon and ends in the early morning.
There are too many tourists in the Tiananmen area, and there are also many people in the surrounding park. It is impossible to carry out work. The park will not start until the tourists have dispersed.
Beijing News: What is the final effect?
Zhang Yong: The effect is obvious.
In the beginning, there were more than 200 flies in a cage, and then only a few were left in individual cages; the mosquitoes were originally 5-6 in a mosquito trap, and it was already 0 before the activity.
Because the manhole cover cannot be opened, the number of rats cannot be counted, but during the entire activity period, there were no accidents such as biting cables.
The national standards for vector density control levels are divided into three levels: A, B, and C. Before the conference, the vector density control level in Tiananmen area reached the highest level A. This is very difficult. Chuangwei generally only requires level C. Only a few areas can reach A level.
This level can ensure that there is no spread of diseases, no bites and harassment, and no rodents can bite cables and cause accidents.
The Beijing News: What is the most curious thing about people around you in the work of vector protection?
Zhang Yong: The most curious thing is how do we know whether there are more or less mosquitoes.
On the one hand, it is the carbon dioxide lamp, on the other hand, it is the trapping method. We will move a small chair, pick a place with many mosquitoes, and expose one side of the leg to trap mosquitoes.
We took an electric mosquito sucker, and when the mosquitoes stopped, we sucked it away, classified, counted, counted, analyzed, and tested the viruses carried by the mosquitoes in the laboratory.
Beijing News: How are the test results?
Are the mosquitoes still clean?
Zhang Yong: It's quite clean, and none of them carry the virus.
Beijing News: Are you very agile and will not be bitten?
Zhang Yong: You still have to be bitten. You stare at this mosquito, and the mosquito bites you. The flower mosquito moves very fast. It is inevitable to be bitten by more than a dozen packets.
Beijing News reporter Dai Xuan