Dengue: Comprehensive NEET 2025 Study Notes on Human Health and Diseases

Dengue: Causes, Symptoms, Prevention, and Control

Introduction to Dengue

Dengue fever is a mosquito-borne viral infection that poses a significant public health challenge, particularly in tropical and subtropical regions. The disease is caused by the dengue virus (DENV), which is transmitted primarily by Aedes aegypti mosquitoes. Understanding the causes, symptoms, prevention, and control measures for dengue is crucial for mitigating its impact.

Causes and Transmission of Dengue

Dengue is caused by the dengue virus, which has four distinct serotypes: DENV-1, DENV-2, DENV-3, and DENV-4. Infection with one serotype provides lifelong immunity to that specific serotype but not to the others, making individuals susceptible to multiple dengue infections over their lifetime.

The primary vector for dengue transmission is the Aedes aegypti mosquito, which thrives in urban environments. These mosquitoes breed in stagnant water found in containers such as buckets, flower pots, and discarded tires. When an Aedes mosquito bites an infected person, it becomes a carrier of the virus. The infected mosquito can then transmit the virus to healthy individuals through subsequent bites.

Symptoms of Dengue Fever

Dengue fever manifests with a wide range of symptoms, varying from mild to severe. The incubation period, which is the time between the mosquito bite and the onset of symptoms, typically ranges from 4 to 10 days. Common symptoms include:

• High fever (up to 104°F or 40°C)
• Severe headache
• Pain behind the eyes
• Joint and muscle pain
• Nausea and vomiting
• Fatigue
• Skin rash, which may appear a few days after the fever begins

Severe dengue, also known as dengue hemorrhagic fever (DHF) or dengue shock syndrome (DSS), can occur in some cases. This form of dengue is characterized by bleeding, blood plasma leakage, and low platelet count, leading to shock, organ failure, and potentially death if not treated promptly.

Prevention of Dengue

Preventing dengue primarily involves controlling the mosquito population and minimizing mosquito bites. Key preventive measures include:

1. Eliminating Breeding Sites: Regularly empty, clean, or cover containers that can hold water to prevent mosquito breeding.
2. Using Mosquito Repellents: Apply insect repellent on exposed skin and clothing to reduce the risk of mosquito bites.
3. Wearing Protective Clothing: Wear long-sleeved shirts, long pants, socks, and shoes, especially during peak mosquito activity times.
4. Installing Screens and Nets: Use window and door screens, and sleep under mosquito nets, especially in areas with high mosquito activity.
5. Community Involvement: Participate in community-based mosquito control programs to reduce mosquito populations.

Control Measures and Government Initiatives

Controlling dengue involves a combination of vector control strategies, public health education, and effective case management. Governments and health organizations implement various initiatives, including:

1. Vector Control Programs: These programs focus on reducing mosquito populations through insecticide spraying, larviciding, and biological control methods.
2. Public Awareness Campaigns: Educating the public about dengue prevention and control measures through media, workshops, and school programs.
3. Surveillance and Monitoring: Monitoring mosquito populations and dengue cases to detect outbreaks early and respond effectively.
4. Healthcare Infrastructure: Strengthening healthcare facilities to manage dengue cases efficiently and provide timely treatment.

Research and Vaccine Development

Researchers are actively working on developing a safe and effective dengue vaccine. The Dengvaxia vaccine, developed by Sanofi Pasteur, has been approved in some countries for individuals aged 9 to 45 who have previously been infected with dengue. However, its use is restricted due to concerns about its safety in dengue-naive individuals.

Ongoing research aims to develop vaccines that provide broader protection against all dengue serotypes and are safe for all age groups. Advancements in vaccine development hold promise for significantly reducing the global burden of dengue in the future.

Conclusion

Dengue fever remains a pressing public health issue, particularly in tropical and subtropical regions. Understanding the causes, symptoms, and preventive measures is crucial for combating this disease. Through effective vector control, public awareness, government initiatives, and advancements in vaccine development, it is possible to reduce the impact of dengue and protect vulnerable populations. Continued efforts in research and community engagement are essential for achieving long-term success in dengue prevention and control.

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