Summer is hot, rainfall increases,
Mosquito vectors are gradually active,
The spread risk of mosquito-borne infectious diseases also increases.
Today we will treat dengue fever.
13 questions that you care about most,
Make it clear at once.
What kind of disease is dengue fever?
Dengue fever is a viral infectious disease caused by dengue virus and mainly spread by the bite of Aedes mosquitoes. It is the most widespread insect-borne infectious disease in the world and is prevalent in more than 100 countries in tropical and subtropical regions.
Dengue virus belongs to flavivirus genus in flaviviridae, and there are four serotypes, which are mainly transmitted by the bites of Aedes aegypti and Aedes albopictus. Clinical manifestations range from asymptomatic to severe dengue fever that may be fatal.
In recent years, with the climate warming, the acceleration of globalization and urbanization, and the change of ecological environment, the global dengue fever epidemic situation is on the rise rapidly.

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Is dengue fever prevalent in China?
In China, dengue fever has not yet formed a stable endemic epidemic, which is mainly characterized by local transmission caused by import, and the epidemic scale is affected by the global dengue fever epidemic. This year, the dengue fever epidemic in China is mainly concentrated in Guangdong, Yunnan, Guangxi and other provinces. At present, there is still the risk of dengue fever transmission in southern China, but as the weather gets colder and the precipitation decreases, the risk of dengue fever transmission will gradually decrease.
What are the characteristics of dengue fever epidemic in China?
In China, dengue fever has not yet formed a stable localized epidemic focus, but mosquito vectors that can transmit dengue virus are widely distributed. In the summer and autumn mosquito breeding season, dengue virus has the potential to spread rapidly after being imported, and local transmission epidemics caused by import occur every year. All endemic areas of dengue fever may be imported into China, but mainly to Southeast Asian countries such as Indonesia, Thailand, Myanmar and Cambodia, and the risk of importing depends on the frequency of people coming and going.
The local epidemic mainly occurred after June, and peaked in August-October. People of all ages can be infected, mainly young and middle-aged, especially those who are active in cross-border exchanges and their related groups.
Is the clinical manifestation of dengue fever serious?
After being infected with dengue virus, it usually takes 5-9 days to get sick, and the symptoms are mostly mild, and some infected people may have no symptoms.
Typical clinical manifestations include sudden fever (up to 39℃), which may be accompanied by obvious fatigue, anorexia, nausea, severe headache, posterior orbital pain, muscle and joint pain (usually called "three pains"), flushing on face, neck and chest (namely "three reds"), and sometimes accompanied by rash and bleeding (nosebleeds and gingival bleeding)
The vast majority of patients can recover within 1-2 weeks, and a few patients progress rapidly after onset, and may have bleeding, shock or even death. Early treatment, early treatment and mosquito isolation can effectively avoid the aggravation of the disease and infect people around you. If you suspect that you are infected with dengue fever, you must take the initiative to see a doctor as soon as possible.

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Which areas are at risk of dengue fever?
Dengue fever is prevalent all the year round in many tropical and subtropical regions, and it is a common and frequently-occurring disease, mainly including South America, Africa, the Middle East, South Asia, Southeast Asia and Pacific island countries. Nearly half of the world’s population (about 4 billion people) live in areas at risk of dengue fever. Large-scale dengue fever outbreaks often occur in Caribbean, Brazil, Costa Rica, Cuba, Guatemala, Honduras, Mexico, Myanmar, Cambodia, Indonesia, Thailand, Laos, Malaysia and Pacific islands. In China, local dengue fever epidemic caused by import often occurs in Yunnan and Guangdong.
Under what circumstances should we consider?
You may have dengue fever?
If you have stayed in countries or regions where dengue fever is prevalent in the past two weeks, or dengue fever has occurred in communities, streets or even cities where you live and work, you should consider the possibility of contracting dengue fever when the above-mentioned suspected dengue fever symptoms suddenly appear. At this time, we should take measures to prevent mosquitoes as soon as possible, such as spraying repellent and wearing long-sleeved underwear, go to the hospital for medical treatment, and take the initiative to explain our travel history to the doctor so as to get a diagnosis and treatment as soon as possible.
How to treat dengue fever?
At present, there is no specific medicine for dengue fever, and support and symptomatic treatment measures are mainly taken, including rest, drinking more water and cooling down.
The fever of dengue fever is mainly reduced by physical cooling. Those with high fever can use acetaminophen and other antipyretic drugs, and avoid using drugs with anticoagulant properties, such as aspirin and other non-steroidal anti-inflammatory drugs (such as ibuprofen). People with deficiency of erythrocyte glucose -6- phosphate dehydrogenase should avoid using antipyretic and analgesic drugs to prevent hemolysis.
Mild patients, such as home treatment, should do a good job of mosquito prevention and isolation, kill adult mosquitoes in the room, avoid family aggregation infection, closely observe symptoms, and see a doctor in time when the condition gets worse.
Can dengue fever be transmitted to family and friends?
After getting dengue fever, you are bitten by Aedes mosquitoes during the infection period (usually lasting until 5 days after the onset), and the virus in your blood can infect mosquito vectors. After 8-10 days of proliferation, mosquitoes are contagious and can transmit the virus to others through bites. Family cluster infection is a frequent event, and mild patients should take effective measures to prevent mosquito isolation during home treatment (for example, using mosquito nets, wearing long-sleeved underwear, using mosquito repellent products, etc.). We should avoid infecting family members with dengue fever and protect their health.

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How is dengue fever spread?
Dengue fever is a mosquito-borne infectious disease, which is mainly transmitted by the bite of Aedes mosquitoes, and generally does not occur from person to person. After Aedes mosquitoes bite dengue fever patients or latent infected people, the virus can spread to others through bites after 8-10 days of proliferation in their bodies.
People in China are generally susceptible to dengue fever, and they may get sick after 5-9 days of infection. Some infected people may not get sick (called recessive infected people), but after infection, they will cause viremia, which is contagious. Perinatal infection of pregnant women can spread vertically and lead to infant infection. Dengue virus can be transmitted through blood through organ transplantation, blood transfusion or the use of blood products. Although there are reports of breastfeeding and sexual transmission, it is extremely rare.
What kinds of Aedes mosquitoes can spread dengue fever?
When is the high incidence of dengue fever?
Aedes mosquitoes of dengue fever are mainly Aedes albopictus and Aedes aegypti, commonly known as "flower mosquitoes", which belong to domestic mosquitoes and mainly breed in places where human beings live and often move. The incidence of dengue fever is seasonal, and the high incidence period is the active period of Aedes mosquitoes. The high incidence season of dengue fever in most parts of China is summer and autumn (August-October), and the local epidemic can start in June or even earlier. In parts of Hainan, Guangdong, Guangxi and Yunnan with warm climate, the high incidence season can be May-November.

Image source: Yunnan CDC
How to prevent dengue fever in daily life?
The best way to prevent dengue fever is to protect yourself from mosquito bites. Use mosquito-repellent incense or electric mosquito-repellent incense liquid in rooms and offices, and at the same time use screen doors, screens and mosquito nets to prevent mosquitoes. Develop good hygiene habits, regularly remove all kinds of accumulated water in families and units. Terraces, potholes, tree holes, bamboo tubes and other places that are prone to accumulated water need to be dredged and leveled regularly, and ditches should be dredged, silt and weeds on the shore should be cleaned, and small containers of garbage should be removed to prevent mosquitoes from breeding. When going to parks, green belts and other places, you should wear long-sleeved clothes and trousers, and apply mosquito repellent drugs to exposed skin and clothes.

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What is the breeding ground of Aedes mosquitoes?
How should it be removed?
The breeding ground is the place where adult mosquitoes lay eggs and mosquito larvae mature and grow. After clearing the breeding ground, Aedes mosquitoes can’t reproduce, which is conducive to blocking the spread of dengue fever. The larvae of Aedes mosquitoes like clean water. Except for adults, the development of the other three stages of the whole breeding cycle is inseparable from water. Therefore, it is an effective means to put containers such as pots and cans upside down to avoid stagnant water and clean up all kinds of useless stagnant water in the home and surrounding areas in time. Aedes mosquitoes can also breed in the accumulated water in a bottle cap or eggshell-sized container, so when clearing the breeding ground, be sure to check carefully and don’t let go of the garbage in the corner.
It is necessary to keep the home and surrounding environment clean and tidy, and remove all kinds of sanitary corners and garbage. Drinking water containers for people and livestock or other useful water containers should be completely changed once a week. Reduce the cultivation of aquatic plants at home, and it is recommended that the containers that have been cultivated be completely changed once a week. Ornamental fish or local species of mosquito-eating fish can be stocked in homes and surrounding landscape waters. Tires should be neatly stored indoors or in rain-proof places, covered tightly with rain-proof cloth outdoors, and discarded tires outdoors should be perforated. For tires with accumulated water that are difficult to remove, you can use phosphorus dichloride to kill young mosquitoes. The vegetation around the home can be used to kill Aedes mosquitoes.
When traveling abroad,
How to prevent dengue fever?
Know the incidence of dengue fever in the destination in advance. The epidemic peak of dengue fever in tropical and subtropical areas is during and after the rainy season.
When going out, you should wear long-sleeved underwear, try to choose light colors, and use mosquito repellent and other mosquito repellent products on bare skin to avoid being bitten by mosquitoes.
When going to areas with high incidence of dengue fever, you can carry foldable mosquito nets with you; During your stay in the local area, close the screen doors and screens; Mosquito-repellent incense and mosquito-repellent aerosol can be used in hotel rooms. Note that Aedes mosquitoes may exist indoors in any type of hotel, so pay attention to mosquito control and mosquito killing.
If you have suspicious symptoms during your stay, you should see a doctor in time and take the initiative to explain the bite.
After returning to the local area, if you have fever within 2 weeks, you should see a doctor in time and explain your travel history. In order not to spread the disease to your family, please cooperate with the local health department and be hospitalized for mosquito isolation treatment. /health science popularization

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Laiyuan | China CDC
Author | Chen Qiulan, Ren Qian, Infectious Diseases Department of China CDC.
Lu Liang, Institute of Infectious Diseases, China CDC
Li Jiandong, Institute of Virology, China CDC
Audit | Infectious Diseases Department of China CDC, Zhang Yanping
Figure source | Yitu. com
Edit | Hu Die
Shengming | Part of the material source network is only used for popular science publicity, such as invasion and deletion.
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Original title: "13 questions about dengue fever that you are most concerned about, make it clear at once"
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