Be alert! Dengue fever is not a ＂small cold＂! Typical symptoms and mosquito prevention knowledge must be known →
Annoying mosquitoes are alive!
On June 5, the National Health and Wellness Commission held a press conference to introduce the health-related situation of seasonal solar terms. Liu Qiyong, a researcher at the China Center for Disease Control and Prevention, said that the national mosquito ecological monitoring data showed that the density of vector Aedes mosquitoes (commonly known as flower mosquitoes) in southern provinces of China was in a period of rapid increase, and there was a risk of the spread of dengue fever in some areas such as Guangdong and Yunnan.
Can you get dengue fever if you are bitten by mosquitoes?How to judge whether your symptoms are dengue fever?Do you really have the physique to attract mosquitoes?Can vitamin B1 really repel mosquitoes?How to choose a safe mosquito repellent?Experts will answer for you.
01.Typical symptoms of dengue fever
1. Dengue fever is also called "bone fracture fever"?
Dengue fever patients often have severe muscle, bone and joint pain, and the pain is severe, as if the bone is about to break, so dengue fever is also called "bone fracture fever".
2. Are the typical symptoms of dengue fever different in different age groups (children/adults)?
Children’s symptoms are relatively atypical, which may only be mild fever and rash, and some children may also have gastrointestinal symptoms such as diarrhea and vomiting.
Typical symptoms of adults include high fever (up to 39-40℃), headache, orbital pain, muscle and joint pain, rash (mostly maculopapular rash or measles-like rash), bleeding tendency (nosebleed, gingival bleeding), etc. It is worth noting that the elderly with chronic basic diseases may have other physical complications.
3. How does Aedes albopictus accelerate its reproduction in the hot and rainy environment in southern summer? What is the regularity of their activity time?
Reasons for accelerating reproduction: It is hot and rainy in summer in the south, and rainwater will form small water bodies in various containers, tree holes, bamboo tubes and other stagnant water places, providing a large number of spawning places for Aedes albopictus. However, entering summer is the peak of mosquito reproduction, and the appropriate temperature (generally 25-32℃) is conducive to the rapid hatching of mosquito eggs, and the growth process of larvae is also shorter than other seasons, so the reproduction speed of Aedes albopictus is particularly fast at this time.
Regularity of activity time: Aedes albopictus is mostly active during the day, and the peak of activity is 8-10 am and 4-6 pm.
4. Will dengue fever spread from person to person? How long does it take for symptoms to appear after being bitten by infected mosquitoes?
Mode of transmission: Dengue fever is a vector-borne disease, which must be transmitted through the bite of Aedes mosquitoes.
But not all Aedes mosquitoes carry dengue virus, and only after being bitten by Aedes mosquitoes that have already carried dengue virus can they get dengue fever.
Generally, there is no direct transmission between people, but the virus in patients’ blood can be transmitted to others under certain circumstances (such as blood transfusion).
Incubation period: After being bitten by Aedes mosquitoes carrying dengue virus, the incubation period is usually 3-14 days, and symptoms may appear in about 5-8 days.
5. How do people distinguish dengue fever from the common cold and COVID-19? What tests are needed for diagnosis?
Symptom differentiation ▼
Dengue fever: high fever, headache, orbital pain, muscle joint pain, rash, bleeding tendency.
Common cold: mainly upper respiratory symptoms such as nasal congestion, runny nose, sore throat and cough, with relatively low fever and mild systemic symptoms.
COVID-19: Fever, dry cough, fatigue, some of them have decreased sense of smell and taste, nasal congestion, runny nose, sore throat, etc., which can seriously cause dyspnea and "white lung" lung infection.
Diagnostic test ▼
Dengue fever: serological detection (detection of dengue antibody) and nucleic acid detection (detection of dengue virus nucleic acid).
Common cold: generally diagnosed according to symptoms, and tested for virus antigen when necessary.
COVID-19: nucleic acid detection, antigen detection and serological antibody detection.
6. Is it risky to take antipyretic drugs (such as ibuprofen) by yourself when symptoms of high fever and rash appear? Which groups of people are prone to develop severe diseases?
Risk of self-medication: When high fever and rash occur in diseases such as dengue fever, self-medication of non-steroidal anti-inflammatory drugs such as ibuprofen may increase the risk of bleeding, because such drugs will inhibit platelet function, which is not conducive to hemostasis of dengue patients.
Severe high-risk groups: the elderly, children, pregnant women, obese people, people with basic diseases (such as hypertension, diabetes, heart disease), and people with low immune function.
7. Why are some people particularly vulnerable to mosquito bites?
(1) Breathing out more carbon dioxide: Mosquitoes are sensitive to carbon dioxide, and people who breathe out more carbon dioxide are more likely to be perceived and located by mosquitoes.
(2) High body surface temperature and love sweating: components such as lactic acid in sweat and high body surface temperature will attract mosquitoes, and sweating will make bacteria on the body surface easy to breed, which will also increase the attraction to mosquitoes.
(3) Fast metabolism: pregnant women and children have fast metabolism, produce more calories and volatile substances, and are easy to attract mosquitoes.
(4) Dress color: Black and other dark-colored shirts and trousers are easy to be targeted by mosquitoes, because they are more likely to absorb heat and form a temperature difference with the surrounding environment, and they prefer to stay on dark-colored items.
02.Correlation between climate in southern China and dengue fever epidemic situation
1. How do the persistent heavy rainfall and hot and humid weather in southern summer create a "hotbed" for mosquito breeding? Which stagnant water areas are most easily overlooked?
Reasons for creating "hotbeds": Heavy rainfall makes all kinds of small containers, pits and basements accumulate water, and hot and humid weather (suitable temperature and high humidity) is conducive to the hatching of mosquito eggs and the growth and development of larvae, providing an ideal breeding environment for mosquito vectors.
Areas easy to ignore water accumulation: flowerpot trays, idle tires, air-conditioning trays, tree holes, water accumulation in bamboo tubes, water accumulation pits in construction sites, school toilets or water storage tanks in unit canteens, etc.
2. In recent years, the cases of dengue fever in Guangdong, Fujian and other places have fluctuated. Is it related to climate warming or urbanization?
Related to climate warming: climate warming makes the temperature in southern China rise, the winter warms, the wintering limit of Aedes mosquitoes moves northward, the living range is expanded, the warm season is prolonged, the number of ant-borne generations is increased, and the chances of virus transmission are also increased.
Related to the process of urbanization: urbanization makes the population dense, and the drainage system is imperfect and there are many sanitary dead corners caused by urban construction, which is easy to form stagnant water and is also conducive to mosquito breeding; At the same time, the frequent movement of people after urbanization increases the risk of dengue fever transmission.
3. After extreme weather events such as typhoon and flood, how should the community quickly carry out mosquito vector prevention and control?
(1) Environmental management: Organize to clean up all kinds of accumulated water in the community, including dumping flowerpot trays, abandoning containers for accumulated water, dredging sewers, and burying potholes.
(2) Chemical control: put slow-release bags in the stagnant water that is difficult to clean up to kill mosquito larvae, and reasonably spray pesticides in mosquito habitats (such as dark corners) to kill adult mosquitoes.
(3) Publicity and education: publicize the knowledge of mosquito control and killing to residents, improve their awareness of self-protection, and encourage residents to take the initiative to clean up the accumulated water around their homes (rooftops, etc.).
03.Personal protection and misunderstanding of dengue fever
04.Policy and public health
1. How to warn the outbreak of dengue fever by monitoring the "Bretu Index" implemented in many southern provinces? How do ordinary residents participate?
Early warning principle: the Brett index is calculated by checking the number of indoor and outdoor small water containers and the breeding situation of Aedes mosquitoes. The higher the index, the higher the density of Aedes mosquitoes and the greater the risk of dengue fever transmission. Generally, if the index exceeds 5, there is a risk of transmission, and if it exceeds 20, there is an outbreak risk.
Residents’ participation: take the initiative to clean up the indoor and outdoor water; Feedback to the community on the situation of mosquitoes breeding in stagnant water; Cooperate with the community to carry out mosquito monitoring and prevention and control work.
In order to facilitate the public to inquire about mosquito vector density and further expand the audience of mosquito vector map, on May 30, 2024, in the drop-down menu of Guangzhou CDC I Health WeChat official account, healthy Guangzhou-mosquito vector map can inquire about the mosquito vector density in 11 districts of Guangzhou in the past half month, and residents can search the mosquito vector density of the whole city, different districts and towns in different monitoring periods to understand the changing trend of mosquito vector density. It also puts forward targeted mosquito vector control measures for different departments and individuals, which provides guidance for individuals and group units to participate in the action of reducing mosquito vector density.
Method for that public to inquire about mosquito density:
① Pay attention to "Guangzhou CDC I Healthy WeChat official account";
② Click on the menu bar "Healthy Guangzhou";
③ Click on "Mosquito Vector Map" to find out the density of mosquito vectors in Guangzhou.
2. What is the current progress of dengue vaccine research and development?
Progress in research and development: There are four serotypes of dengue fever. Different serotypes are prone to cross-reaction and lead to antibody dependence enhancement (ADE) effect, which will aggravate the disease. Therefore, it is the biggest obstacle to the current vaccine research and development to effectively prevent the infection of different dengue serotypes and avoid cross-reaction.
After years of research by scholars from all over the world, some dengue vaccines are currently in the clinical trial stage, and some vaccines have been approved for use in some countries, but the effectiveness and safety of vaccines still need to be continuously evaluated and optimized. At present, there is no approved dengue vaccine available to the public in China.
05.Summer vacation travel reminder
In summer, residents’ travel opportunities increase. Which countries have a high incidence of dengue fever? What should we pay attention to when traveling? What should I do if I have a sudden fever after traveling to Southeast Asia?
High-incidence countries of dengue fever: Dengue fever is mainly prevalent in tropical and subtropical areas, with high incidence in tropical and subtropical countries such as Southeast Asia (such as Thailand, Malaysia and the Philippines), South America (such as Brazil and Colombia) and the Caribbean (such as Haiti and Dominica).
Precautions for travel: Before leaving the country, you can check the official website of the World Health Organization, the health tips issued by the local embassy of China or local news reports to understand the dengue epidemic situation at the destination; Remember three points of personal protection: long-sleeved clothes to prevent bites, mosquito net isolation+mosquito repellent double protection, and avoid going to mosquito-populated areas at dawn and dusk; If fever, headache, rash and other symptoms appear, seek medical advice in time and take the initiative to inform the doctor of his travel history.
Treatment of fever after returning to China: seek medical advice in time and actively inform the doctor of his recent overseas travel history so that the doctor can quickly investigate mosquito-borne infectious diseases such as dengue fever; Personal protection should be done during medical treatment to prevent mosquitoes from spreading to others after biting themselves.
Coordinator: Yang Yang and Lai Bixia
Author: Liang Xueying
Editor: lee Jenrya
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