Wolbachia-Infected Mosquitoes for Dengue Control | 19 Aug 2024

Source: TH

Why in News?

Dengue fever, chikungunya, and Zika virus represent major public health challenges in India, leading to considerable economic losses and healthcare burdens. 

• The limited success of traditional control methods underscores the need for innovative strategies, such as the use of Wolbachia-infected mosquitoes, which offer a promising alternative.

How does Wolbachia Help in Controlling Mosquito Populations?

• About:

  • Wolbachia is a common type of bacteria found in insects. Approximately 6 in 10 of all insects, including butterflies, bees, and beetles, around the world have Wolbachia. 

    • Wolbachia bacteria cannot make people or animals (for example, fish, birds, pets) sick.

    • They are not found in Aedes Aegypti mosquitoes.
  • Aedes aegypti can spread viruses including dengue, Zika, and chikungunya.
  • Aedes mosquitoes with Wolbachia can be used to reduce the number of target mosquito species. 
    • Mosquitoes with Wolbachia are not genetically modified.
• Process of Production: Wolbachia bacteria are first introduced into the eggs of male and female Aedes Aegypti mosquitoes. 
  • The eggs are then used to mass-produce new mosquitoes infected with Wolbachia. 
    • There are 2 Wolbachia strains, wMel and wAlbB, that have been transinfected into Aedes Aegypti mosquitoes for population replacement.
  • After production, the mosquitoes are sorted by sex, with only the males being retained for release, while the females are kept for further breeding in the laboratory.
• Use for Mosquito Control: Wolbachia-infected mosquitoes are used to lower the population of target species like Aedes Aegypti, the yellow fever mosquito, that can spread dengue fever, chikungunya, Zika fever, Mayaro etc. 
  • Control professionals release male Aedes Aegypti mosquitoes carrying Wolbachia into areas with wild Aedes Aegypti. 
  • When these males mate with wild females that lack Wolbachia, the eggs produced do not hatch. As a result, the population of Aedes Aegypti mosquitoes decreased.
• Status of Wolbachia Programs in India: India currently lacks an active Wolbachia mosquito release program. 
  • The Indian Council of Medical Research - Vector Control Research Center (ICMR-VCRC) has initiated the development of wMel Aedes strains but has faced delays in public updates and government approvals. 
  • Recent findings indicate the natural presence of Wolbachia in Aedes mosquitoes in Northeast India, though its immediate significance is unknown.

Global Examples for Wolbachia Implementation

• In Singapore, the release of infected male mosquitoes resulted in a 90% reduction in the Aedes population and a 77% decrease in dengue cases in release areas. 
• Australia adopted a population replacement strategy, leading to a stable wMel strain genome in wild populations and significant reductions in dengue incidence. 
• A landmark randomised controlled trial in Indonesia demonstrated that areas with released wMel (strain) mosquitoes experienced a 77% reduction in dengue cases and an 86% decrease in hospitalizations.