Dengue fever is an acute infectious disease caused by a mosquito-borne virus, primarily transmitted through bites from infected mosquitoes. This viral disease is widespread in tropical and subtropical regions around the world, especially prone to outbreaks during the rainy season or in hot and humid environments. According to statistics from the World Health Organization, approximately 100 million people are infected with this disease globally each year, with the number of cases showing an increasing trend year by year.
The virus is transmitted through bites from Aedes aegypti and Aedes albopictus mosquitoes. After humans are infected, they may exhibit various clinical symptoms, and in severe cases, it can lead to bleeding phenomena or shock syndrome. Although the vast majority of patients experience mild symptoms, the mortality rate for severe cases can exceed 20%, which is why public health authorities take this disease very seriously.
The pathogen of dengue fever is the dengue virus, which has four serotypes numbered from 1 to 4. After replicating in the mosquito, the virus enters the human bloodstream through its saliva. When a mosquito bites an infected person, the virus completes a 7-10 day incubation period within the mosquito before it becomes capable of transmission. This biological characteristic makes epidemic control extremely challenging, as mosquitoes can become long-term carriers of the virus.
Risk factors are mainly related to geographical environment and personal behavior. Living in or traveling to endemic areas, lack of mosquito prevention measures, and having many stagnant water sources in the living environment (such as flower vases and discarded containers) all increase the risk of infection. Individuals with weakened immune systems (such as young children and the elderly) or those who have previously been infected with other types of dengue virus may experience more severe hemorrhagic dengue fever if they are reinfected with a different serotype.
After infection, there is usually an incubation period of 3-14 days, followed by the acute phase of the disease. Typical symptoms include high fever (39-40°C), severe headache, retro-orbital pain, muscle pain, and rash. About 5%-20% of patients may experience a "dengue symptom complex," which may be accompanied by lymphadenopathy and a decrease in white blood cell count.
A small number of cases may progress to severe forms, presenting with bleeding tendencies (such as gum bleeding and subcutaneous bruising), hypotension, and signs of shock due to inadequate organ perfusion. This progression often occurs after the fifth day of fever, known as the "critical phase," during which viremia subsides but the immune system overreacts, leading to vascular leakage.
According to the World Health Organization classification, symptoms can be divided into:
Clinical diagnosis primarily relies on symptom assessment and epidemiological history inquiry, including recent mosquito bite history and travel history to endemic areas. Laboratory tests include complete blood count (to observe thrombocytopenia), viral RNA testing, and antibody testing. NS1 antigen testing during the acute phase can facilitate early diagnosis, while serology during the recovery phase is used to confirm IgM/IgG antibody conversion.
Differential diagnosis must exclude other febrile illnesses, such as influenza, malaria, or the differences between dengue and chikungunya virus infections. During an outbreak, rapid antigen test strips can effectively classify suspected cases, but confirmation still relies on precise laboratory testing.
The diagnostic process typically includes:
Currently, there are no specific antiviral drugs available, and treatment is primarily supportive. Patients with high fever require physical cooling and fluid replacement, while those with severe dehydration need intravenous fluid therapy to maintain blood volume. Pain management uses acetaminophen instead of non-steroidal anti-inflammatory drugs, as the latter may exacerbate bleeding tendencies.
Severe patients need to be admitted to intensive care for monitoring of blood pressure and organ function, and may require platelet transfusions or fresh frozen plasma. The latest therapies include experimental treatments with monoclonal antibody drugs (such as Tocilizumab) for cytokine storms, but these are not yet widely used. Traditional antiviral drugs like Takhminavir are currently in phase III clinical trials.
Treatment principles can be summarized as follows:
Prevention strategies mainly focus on interrupting the mosquito transmission cycle. Environmental control includes removing stagnant water containers, using insecticides to treat reservoirs, and regularly spraying adulticides in high-risk areas. Personal protection involves wearing long-sleeved clothing, using mosquito repellent containing DEET, and installing mosquito nets indoors.
Regarding vaccination, the Tetravalent Dengue Vaccine (TDV) has been approved in several countries, but age restrictions for vaccination and vaccine efficacy vary by serotype. It is recommended that a physician assess infection history and immune status before vaccination to avoid exacerbating the condition due to the "antibody-dependent enhancement" effect.
Community prevention measures include:
If the following symptoms occur, seek medical attention immediately: high fever lasting more than three days, unexplained bruising or bleeding spots, persistent vomiting, worsening abdominal pain, shortness of breath, or changes in consciousness. These signs may indicate a worsening condition leading to the bleeding phase or pre-shock.
Individuals who have previously been infected with dengue should pay special attention to changes in symptoms if they are reinfected with a different serotype. Pregnant women or patients with chronic diseases should seek medical evaluation as soon as possible, even if symptoms are mild. During an outbreak, if typical triad symptoms (facial flushing, conjunctival injection, and neck flushing) appear, they should be regarded as high-risk signs.
The following situations require immediate medical attention:
The symptoms of dengue fever, such as fever, headache, and muscle pain, are similar to those of a cold, but dengue fever is often accompanied by retro-orbital pain, skin rash, and severe pain in the limbs and joints (commonly referred to as "breakbone fever"). If persistent high fever lasts more than 3 days, frequent vomiting, or subcutaneous bleeding occurs, seek medical attention immediately, as these are warning signs that are clearly different from a common cold.
What dietary or activity restrictions should be observed during the recovery period after a dengue infection?During the recovery period, excessive activity should be avoided, as the virus may affect platelet counts, and vigorous exercise may increase the risk of internal bleeding. In terms of diet, it is recommended to choose easily digestible foods, such as rice porridge and vegetable soup, and to maintain adequate hydration and electrolyte levels, avoiding alcohol and spicy foods to reduce liver burden.
Will individuals who have previously been infected with dengue develop immunity to other virus types?After infection with one type of dengue virus, immunity to that specific type will develop, but if reinfected with a different type of virus, the condition may worsen due to "antibody-dependent enhancement." Therefore, individuals who have been infected still need to strictly prevent mosquito bites and should not become complacent due to existing immunity.
How can residents in dengue-endemic areas reduce mosquito breeding in their home environments?Removing stagnant water containers around the home (such as flower vases and discarded cans) is key, as Aedes aegypti larvae often breed in clean water. Using window screens, mosquito nets, and mosquito repellent containing DEET can enhance personal protection. Communities should regularly spray insecticides and maintain dry environments to interrupt the mosquito lifecycle.
After symptoms of dengue fever have alleviated, how long can patients return to their normal routines?Mild cases typically allow for gradual recovery within 1-2 weeks, but some patients may take longer due to immune system impairment. Physicians recommend avoiding strenuous activities within one month after recovery and regularly monitoring platelet counts. If there have been instances of bleeding or severe symptoms like shock, follow the physician's guidance to extend the recovery period.
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