Dengue fever is a mosquito-borne viral infection that poses a significant health threat in tropical and subtropical regions worldwide. Transmitted primarily by the Aedes aegypti mosquito, dengue affects millions annually, with a substantial portion of the global population at risk. Understanding its transmission, symptoms, treatment, and prevention is crucial for mitigating its impact.
Transmission and Epidemiology
The dengue virus (DENV), which causes dengue, comes in four different serotypes: DENV-1, DENV-2, DENV-3, and DENV-4. The virus is transmitted to humans through the bites of infected female mosquitoes, mainly Aedes aegypti and, to a lesser extent, Aedes albopictus. These mosquitoes thrive in urban and semi-urban areas, breeding in stagnant water found in containers like buckets, flower pots, and discarded tires.
The global incidence of dengue has surged dramatically in recent decades. According to the World Health Organization (WHO), about half of the world’s population is now at risk, with an estimated 100–400 million infections occurring each year. Factors contributing to this rise include rapid urbanization, increased international travel, and climate change, which expands the habitats suitable for Aedes mosquitoes.
Symptoms and Clinical Manifestations
Dengue infection can range from asymptomatic or mild illness to severe disease. When symptoms do occur, they typically begin 4–10 days after the mosquito bite and last for 2–7 days. Common symptoms include:
- High fever (up to 40°C or 104°F)
- Severe headache
- Pain behind the eyes
- Muscle and joint pains
- Nausea and vomiting
- Swollen glands
- Rash
In some cases, the disease can progress to severe dengue, previously known as dengue hemorrhagic fever or dengue shock syndrome. Severe dengue is a medical emergency characterized by:
- Severe abdominal pain
- Persistent vomiting
- Rapid breathing
- Bleeding gums or nose
- Fatigue and restlessness
- Blood in vomit or stool
Without proper medical care, severe dengue can lead to plasma leakage, fluid accumulation, respiratory distress, severe bleeding, or organ impairment, potentially resulting in death.
Diagnosis
Diagnosing dengue involves clinical evaluation and laboratory tests. Healthcare providers should consider dengue in patients presenting with a high fever and two or more of the aforementioned symptoms, especially if they reside in or have recently traveled to dengue-endemic areas. Laboratory confirmation is achieved through tests detecting the virus, viral nucleic acid, antigens, or antibodies. Early diagnosis is vital for effective management and reducing the risk of complications.
Treatment
There is no specific antiviral treatment for dengue. Management focuses on relieving symptoms and maintaining fluid balance. Key aspects include:
- Hydration: Adequate fluid intake is crucial to prevent dehydration caused by fever and vomiting.
- Pain Relief: Paracetamol (acetaminophen) is recommended to alleviate pain and reduce fever. Aspirin and ibuprofen are examples of non-steroidal anti-inflammatory medicines (NSAIDs) that should be avoided since they raise the risk of bleeding.
- Medical Monitoring: Patients, especially those with warning signs of severe dengue, should be monitored closely for at least 48 hours after the fever subsides to manage any complications promptly.
In cases of severe dengue, hospitalization is necessary. Treatment may involve intravenous fluid replacement, blood transfusions, and careful monitoring in an intensive care setting.
Prevention
Preventing dengue primarily involves controlling mosquito populations and minimizing exposure to mosquito bites. Effective strategies include:
- Eliminating Breeding Sites: Regularly empty, clean, or cover containers that can hold water, such as buckets, flower pots, and discarded tires, to prevent mosquitoes from breeding.
- Personal Protection: Use mosquito repellents containing DEET, wear long-sleeved clothing, and use mosquito nets or screens to reduce the risk of bites.
- Community Engagement: Public health campaigns and community participation are essential to sustain mosquito control efforts and raise awareness about dengue prevention.
Vaccination is another preventive measure. As of now, two dengue vaccines have been approved:
- Dengvaxia (CYD-TDV): Approved in several countries for individuals aged 9–45 years who have had a previous dengue infection. It is not recommended for those without prior dengue exposure due to the risk of severe dengue upon subsequent infection.
- Qdenga (TAK-003): Recently approved in some regions, this vaccine is indicated for individuals aged 4 years and older, regardless of previous dengue infection history.
The World Health Organization emphasizes that vaccination should complement, not replace, other preventive measures like vector control and community engagement.
Global Impact and Future Outlook
Dengue remains a significant public health challenge, particularly in tropical and subtropical regions. The increasing incidence underscores the need for comprehensive strategies combining vector control, effective case management, surveillance, and vaccination where appropriate. Continued research is essential to develop more effective vaccines and treatments, as well as to understand the impact of factors
