DENGUE
Dengue, often called “break-bone fever”, is a mosquito-borne viral infection that continues to threaten millions of people around the world. Countries like India have been especially affected.
What Is Dengue?
Dengue is caused by the dengue virus, which spreads to humans through the bite of infected mosquitoes. It is more common in tropical and subtropical regions where warm temperatures and urban environments help mosquitoes breed easily.
How Dengue Spreads
1. Mosquito-to-Human Transmission
The infection is mainly transmitted through the bite of infected Aedes aegypti mosquitoes. These mosquitoes are active during the day, especially early morning and late afternoon.
Another species, Aedes albopictus, can also spread the virus but contributes less to transmission.
2. Human-to-Mosquito Transmission
A mosquito can become infected when it bites a person who already has dengue virus in their bloodstream.
3. Human-to-Human Transmission
Direct human-to-human spread is uncommon. However, maternal transmission (mother to baby) has been reported.
4. Other Rare Modes
Rare cases of dengue have occurred through blood transfusions, organ donations and transovarial transmission (virus passed from an infected female mosquito to its eggs)
Symptoms of Dengue
Common Symptoms: Most people experience mild or no symptoms and recover within 1–2 weeks. Typical symptoms include high fever, severe headache, body aches and joint pain, nausea and skin rash
Severe Dengue: Severe dengue can be life-threatening. It usually appears once the fever reduces. Warning signs include intense abdominal pain, persistent vomiting, rapid breathing, bleeding from gums or nose, blood in vomit or stool.
Immediate medical attention is necessary.
Who is at risk?
1. Previous Dengue Infection
People who have had dengue before are at a higher risk of severe dengue, due to a phenomenon called antibody-dependent enhancement.
2. Unplanned Urbanisation
Uncontrolled population growth and environmental conditions increase mosquito breeding. Risk factors include high population density, water storage practices, human mobility and irregular water supply.
Global Situation: Dengue has now become one of the top 10 global health threats, as identified by WHO in 2019.
Key Facts
● Around half of the world’s population is at risk.
● An estimated 100–400 million infections occur every year.
● Since many cases are mild or misdiagnosed, the actual number is likely much higher.
Where Is Dengue Most Common?
Dengue is widespread in:
● The Americas
● South-East Asia
● Western Pacific
Asia alone accounts for nearly 70% of the global disease burden.
Europe, too, has begun reporting local transmission—first noted in France in 2010.
Dengue in India
According to ICMR, 2 to 2.5 lakh cases are reported annually across the country.
Prevention: The Best Protection
● There is no complete cure for dengue yet. Preventing mosquito bites is the safest approach.
● Protect Yourself From Mosquito Bites
● Wear clothes that cover the arms and legs
● Use mosquito nets
● Apply repellents containing DEET, Picaridin, or IR3535
● Keep surroundings clean and free of still water
Treatment
For Mild Dengue
● Drink plenty of fluids
● Use paracetamol (acetaminophen) for fever
● Avoid ibuprofen and aspirin, as they increase the risk of bleeding
For Severe Dengue
Hospitalisation is required for close monitoring, hydration, and supportive care.
Vaccines
Currently, Dengvaxia is the only licensed vaccine in some countries, but it is effective only for people who have had dengue before.
Ideal Characteristics of a Dengue Vaccine
Scientists aim to develop a vaccine that:
● Is safe in both the short and long term
● Protects against all four dengue virus serotypes
● Reduces risk of severe disease and death
● Works regardless of the person’s age or previous infection
● Provides sustained immunity
India’s upcoming vaccine project is a major step toward meeting these goals.
Steps Taken to Control Dengue
WHO’s Response
WHO supports countries through:
● Global Vector Control Response (2017–2030)
● Strengthening monitoring and prevention strategies
India’s Measures
India implements control through the National Vector Borne Diseases Control Programme (NVBDCP).
It covers six diseases: Malaria, Kala-azar, Lymphatic filariasis, Dengue, Chikungunya and Japanese encephalitis
The programme focuses on mosquito control, disease surveillance, public awareness, and early diagnosis.
Conclusion: Dengue remains a serious public health challenge in many parts of the world, including India. With rising cases and expanding geographical spread, prevention and awareness have become more important than ever. The development of India’s dengue vaccine offers hope for stronger protection in the coming years. Controlling mosquito breeding and seeking timely medical care remain the most powerful tools against this disease.