Wolbachia: an unlikely hero
- November 6, 2023
- Posted by: OptimizeIAS Team
- Category: DPN Topics
Wolbachia: an unlikely hero
Subject : Science and Tech
- Wolbachia is a genus of bacteria that has evolved complex relationships with the many insects that can host it.
- It is named for the American pathologist Simeon Burt Wolbach, who identified it along with Marshall Hertig in 1924.
- In 1971, researchers discovered that when male Culex mosquitoes infected by Wolbachia bacteria fertilised healthy eggs from a female, the eggs died.
- The bacteria modified the male’s sperm cells in a way that only the bacteria could reverse. So, if the female mosquito was uninfected, her egg cells would be damaged.
- But if the female was infected by Wolbachia, the eggs would be viable if the male was uninfected or infected by the same strain of Wolbachia.
- This means infected female mosquitoes gain a reproductive advantage over time as the amount of Wolbachia in the population increases.
- Wolbachia can also reduce the rate at which chikungunya and yellow fever viruses multiply in infected mosquitoes.
- Scientists have also found that some Wolbachia species can strongly protect some mosquito species against the malaria parasite. So, they are currently studying a way to have the right strain of Wolbachia rapidly spread in a particular mosquito population, in the right environmental conditions, such that the bacteria can suppress malaria transmission.
- If this is achieved, it will be a significant weapon in our millennia long fight against mosquito borne diseases.
How mosquitoes spread disease?
- Mosquitoes pick up viruses by biting infected people. When they bite again, they can transmit the virus to the next person. This is how mosquito-borne diseases spread.
- Mosquitoes do not naturally carry viruses – they can only get them from infected people.
- Since only female mosquitoes bite humans, only female mosquitoes can transmit viruses.
- The Aedes aegypti mosquito is the main transmitter of dengue, Zika, chikungunya and yellow fever viruses.
- Aedes aegypti mosquitoes originated in Africa, but they have spread through tropical and subtropical regions around the world.
- Aedes aegypti mosquitoes first spread outside Africa during the slave trade between the 15th and 19th centuries. They also spread through trade with Asia during the 18th and 19th centuries, and then again following troop movements in World War II.
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 is safe for humans and the environment. Independent risk analyses indicate that the release of Wolbachia mosquitoes poses negligible risk to humans and the environment.
- Wolbachia lives inside insect cells and is 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.
How our Wolbachia method works
It was discovered that when 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.
So, at the World Mosquito Program, we breed Wolbachia mosquitoes. Then, in partnership with local communities, we release them into areas affected by mosquito-borne diseases.
Which means less risk of disease in communities where Wolbachia is established in the local mosquito population.
Why this method is unique and effective?
- Unlike most other techniques that aim to prevent mosquito-borne diseases, our Wolbachia method is natural and self-sustaining.
- This method does not suppress mosquito populations or involve genetic modification (GM), as the genetic material of the mosquito is not altered.
World Mosquito Program (WMP)
It is a not-for-profit group of companies owned by Monash University that works to protect the global community from mosquito-borne diseases such as dengue, Zika, yellow fever and chikungunya.
Since releasing the first Wolbachia mosquitoes in 2011, evidence from international pilot studies shows that we can use Wolbachia more broadly to decrease the risk of Aedes aegypti mosquitoes transmitting viruses. Multiple trials in various locations demonstrate that our method is a safe and effective way to help prevent the spread of diseases across entire cities and regions.
We continue to rapidly expand our operations by building partnerships with local governments and communities around the world who are embracing our Wolbachia method.