Dengue fever

Dengue fever

Why in news:

  • The recent surge in dengue cases globally, including in new regions has been alarming and poses significant global health challenges.
  • The WHO forecasts the possibility of record­level cases this year due to global warming favouring disease­transmitting mosquitoes.

About Dengue fever:

  • Dengue (break-bone fever) is a viral infection that spreads from mosquitoes to people.
  • It is more common in tropical and subtropical climates.
  • Most people who get dengue won’t have symptoms.
  • But for those that do, the most common symptoms are high fever, headache, body aches, nausea and rash.
  • In severe cases, dengue can be fatal.
  • Dengue is treated with pain medicine as there is no specific treatment currently.


  • Most people with dengue have mild or no symptoms and will get better in 1–2 weeks.
  • Rarely, dengue can be severe and lead to death.
  • If symptoms occur, they usually begin 4–10 days after infection and last for 2–7 days.

Symptoms may include:

  • high fever (40°C/104°F)
  • severe headache
  • pain behind the eyes
  • muscle and joint pains
  • nausea
  • vomiting
  • swollen glands
  • rash
  • Individuals who are infected for the second time are at greater risk of severe dengue.

Diagnostics and treatment:

  • Most cases of dengue fever can be treated at home with pain medicine.
  • Preventing mosquito bites is the best way to avoid getting dengue.
  • There is no specific treatment for dengue. The focus is on treating pain symptoms.
  • Acetaminophen (paracetamol) is often used to control pain.
  • Non-steroidal anti-inflammatory drugs like ibuprofen and aspirin are avoided as they can increase the risk of bleeding.
  • There is a vaccine called Dengvaxia for people who have had dengue at least once and live in places where the disease is common.
  • For people with severe dengue, hospitalization is often needed.


Transmission through the mosquito bite:

  • The virus is transmitted to humans through the bites of infected female mosquitoes, primarily the Aedes aegypti
  • Other species within the Aedes genus can also act as vectors, but their contribution is secondary to Aedes aegypti.

Human-to-mosquito transmission:

  • Mosquitoes can become infected by people who are viremic with DENV.
  • This can be someone who has a symptomatic dengue infection, someone who is yet to have a symptomatic infection (they are pre-symptomatic), but also people who show no signs of illness as well (they are asymptomatic).
  • Human-to-mosquito transmission can occur up to 2 days before someone shows symptoms of the illness, and up to 2 days after the fever has resolved.

Maternal transmission:

  • The primary mode of transmission of DENV between humans involves mosquito vectors.
  • There is evidence however, of the possibility of maternal transmission (from a pregnant mother to her baby)

Syllabus: Prelims