Wolbachia Bacteria to take on Dengue, Zika


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    Wolbachia bacteria will help to an end to dengue, chikungunya and zika  by blocking the proliferation of harmful viruses but doesn’t harm the mosquitoes themselves.

    Findings of Vector Control Research Centre (VCRC) 

    • The scientists have been cross-breeding local Aedes aegypti mosquitoes, which transmit dengue, chikungunya and zika virus, with mosquitoes that carry the Wolbachia bacteria from Australia’s Monash University. 
    • In this manner, after six to seven generations, the mosquitoes will have genetic material closest to that of the Indian Aedes aegypti strain while the Wolbachia are inherited from the Australian strains
    • This strategy was successfully adopted in Australia’s Queensland during a dengue outbreak.
    • So far, the research has been limited to the laboratories; once it is approved by the government, a pilot will be done by releasing the Wolbachia-carrying mosquitoes in the community.

    What is Wolbachia?

    • Wolbachia are extremely common bacteria that occur naturally in 50 per cent of insect species, including some mosquitoes, fruit flies, moths, dragonflies and butterflies.
    • Wolbachia are safe for humans and the environment. 
    • Independent risk analyses indicate that the release of Wolbachia-infected mosquitoes poses negligible risk to humans and the environment.
    • Wolbachia live inside insect cells and are passed from one generation to the next through an insect’s eggs. 
    • Aedes aegypti mosquitoes don’t normally carry Wolbachia, however many other mosquitoes do.
    • The Wolbachia is maternally transmitted from mother to offspring, and gradually spreads across the population. 
    • The Wolbachia inhibits the multiplication of the dengue virus when present in the mosquitoes. 
    • The number and frequency of Wolbachia in mosquitoes is determined by molecular tests.

    How Wolbachia method works?

    • Aedes aegypti mosquitoes carry Wolbachia, the bacteria compete with viruses like dengue, Zika, chikungunya and yellow fever.
    • This makes it harder for viruses to reproduce inside the mosquitoes. And the mosquitoes are much less likely to spread viruses from person to person.
    • This means that when Aedes aegypti mosquitoes carry natural Wolbachia bacteria, the transmission of viruses like dengue, Zika, chikungunya and yellow fever is reduced.

    Approaches to use Wolbachia

    • There are two approaches to tackling dengue with Wolbachia. 
    • The first involves releasing only modified male mosquitoes. 
      • Since 2015, this strategy has been successfully adopted in Singapore and Guangzhou, China, and in parts of the United States, such as Miami, Texas and California. 
      • Because eggs produced from unmodified females that mate with modified males do not hatch, the number of mosquitoes in the community is greatly reduced.
    • The second approach, used by some cities in Vietnam, Indonesia, Malaysia, Brazil and Australia, among others, involves releasing modified mosquitoes of both sexes. 
      • The infected females pass the bacteria to their offspring.
      •  Over time (several months to years, depending on characteristics of the release site), the modified mosquitoes replace the native population.

    Source: BS