Wolbachia Method

The Wolbachia method is the technique by which the dengue-transmitting aedes aegypti mosquito will be unable to spread the disease. In this method, a bacteria called Wolbachia is injected into the mosquito, which will suppress the viruses inside the mosquito and hence stop the spread of diseases. This programme is being run by a non-profit organisation named the World Mosquito Programme(WMP). The trials conducted by the WMP are showing promising results and could be replicated all around the world.

Aedes aegypti is a mosquito that transmits diseases like dengue, yellow fever, chikungunya, and zika fever among others. It originated in Africa but soon spread to other parts of the world. It is now found in most tropical and subtropical countries. It has characteristic white markings on the legs. It has a life span of two to three weeks, but its eggs can survive over a year in a dry state. It is a vector for numerous disease-causing pathogens. To control its spread, various techniques are being deployed all over the world, such as use of insecticides, genetic modification techniques, the Wolbachia method etc. The Wolbachia method has shown promise because it does not affect the environment and uses non-GMO techniques.

• In this method, the Wolbachia bacteria is procured from a fruit fly and injected into the eggs of the mosquito. The technique to introduce Wolbachia bacteria into insect eggs is Microinjection.
• Once inside the mosquito, the bacteria can be naturally passed onto future generations. (see box)
• Inside the mosquito, bacteria inhibit the growth of the virus in the following two ways:
• It can boost the immune system of the mosquito, which makes it harder for the virus to survive inside the mosquito.
• Wolbachia also competes with the virus for key molecules such as cholesterol. Both need cholesterol to survive, but Wolbachia prevails in obtaining the molecule, hence virus growth is suppressed.
• If the virus cannot grow inside the mosquito, it cannot spread with the mosquito bite.
• WMP has been releasing the Wolbachia infected in the environment, and a very significant decrease in dengue cases has been observed in the trial areas.

• Bacteria: Wolbachia is a genus of bacteria named after the scientist Simeon Burt Wolbach who discovered it in 1924. It is naturally found in mosquitoes and upto 50 % of the species.
• Dependent: It depends on the insects for its survival as it cannot survive on its own in the environment (outside the insect body). It is not a parasite.
• It is not naturally found in aedes aegypti.

• Non-Genetically Modified Organism: There is no genetic modification involved in this method, hence the associated risks are not there.
• No harm to the environment.
• No harm to humans.
• Wolbachia infected mosquitoes can be released in large numbers.
• Does not affect the number of other mosquitoes; hence it does not aid in the increase of other diseases such as malaria.

• A non-profit working to protect the world from mosquito borne disease.
• It is funded by the Bill and Melinda Gates foundation through the Grand Challenge in Global Health Program.
• The group of companies are owned by Monash University, Australia.

• Project Wolbachia is a program run by the National Environment Agency, Singapore. It is different from the Wolbachia method of WMP because it is a suppression method as opposed to the replacement method of WMP.
• Project Wolbachia involves the release of non-biting male aedes aegypti mosquitoes at some locations. When they breed with the female mosquitoes, the eggs produced are not able to hatch; hence, there is a decrease in the overall population of mosquitoes.

According to the Centers for Disease Control (CDC), around 400 million people get infected with dengue, and around 40 thousand people die from it. Other diseases, such as Chikungunya fever, yellow fever, etc also affect millions. Hence it is very important to control the population of disease carrying mosquitoes. The Wolbachia method of WMP provides for a novel method of inhibiting the said diseases. Since the initial trials are showing promising results, it provides a ray of hope for other regions in reducing the disease burden.