Dengue

• 26 Oct 2023

Source: DTE

Why in news?

Recently, Dengue cases have surged significantly in some states like Uttar Pradesh, West Bengal, and Tamil Nadu.

What is Dengue?

• About:
  • Dengue is a self-limiting febrile illness with symptoms ranging from asymptomatic to severe.
  • Dengue is a mosquito-borne tropical disease caused by the dengue virus (Genus Flavivirus), transmitted by several species of female mosquito within the genus Aedes, principally Aedes aegypti.
    • This mosquito also transmits chikungunya and Zika infection.
• Serotypes of Dengue:
  • There are 4 distinct, but closely related, serotypes (separate groups within a species of microorganisms that all share a similar characteristic) of the virus that cause dengue (DEN-1, DEN-2, DEN-3 and DEN-4).
• Symptoms:
  • Sudden high fever, severe headaches, pain behind the eyes, severe bone, joint, and muscle pain, etc.
• Dengue Vaccine:
  • The dengue vaccine CYD-TDV or Dengvaxia was approved by the US Food & Drug Administration in 2019, the first dengue vaccine to get the regulatory nod in the US.
    • Dengvaxia is basically a live, attenuated dengue virus which has to be administered in people of ages 9 to 16 who have laboratory-confirmed previous dengue infection and who live in endemic areas.
  • Researchers at India’s National Centre for Biological Sciences, in collaboration with nine other institutions in India, Africa, and the US, have developed India’s first and only DNA vaccine candidate for dengue fever.
    • In preliminary trials on mice, the candidate generated a robust immune response and improved survival rates after exposure to the disease.
• Controlling Dengue Using Bacteria:
  • Researchers from the World Mosquito Program have used mosquitoes infected with Wolbachia bacteria to successfully control dengue, leading to a 77% reduction in incidence in Indonesia.

What is DNA Vaccine?

• A DNA vaccine is a type of vaccine that uses a small piece of DNA that codes for a specific antigen (a molecule that triggers an immune response) from a pathogen, such as a virus or bacterium, to stimulate an immune response.
• The DNA is injected directly into the body's cells, where it instructs the cells to produce the antigen.
  • The immune system then recognizes the antigen as foreign and mounts an immune response against it, which helps to develop immunity to the pathogen.
• DNA vaccines are third-generation vaccines.
• The ZyCoV-D is the world's first and India's indigenously developed DNA based vaccine for Covid-19.

UPSC Civil Services Examination, Previous Year Questions (PYQs)

Prelims

Q.1 Consider the following statements: (2017)

1. In tropical regions, Zika virus disease is transmitted by the same mosquito that transmits dengue.
2. Sexual transmission of Zika virus disease is possible.

Which of the statements given above is/are correct?

(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2

Ans: (c)

Q.2 ‘Wolbachia method’ is sometimes talked about with reference to which one of the following? (2023)

(a) Controlling the viral diseases spread by mosquitoes
(b) Converting crop residues into packing material
(c) Producing biodegradable plastics
(d) Producing biochar from thermo-chemical conversion of biomass

Ans: (a)