How WMP's Wolbachia method works Skip to main content

When Aedes aegypti mosquitoes carry natural bacteria called Wolbachia, they reduce the mosquitoes’ ability to transmit viruses like dengue, Zika, chikungunya and yellow fever. Find out how.

Aedes Agypti

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

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.

child in hospital with yellow fever, Indonesia

The number of people affected by mosquito-borne diseases is rapidly growing.

In recent years, population growth, the movement of people from rural areas to cities, more international travel and climate change have all increased the spread of Aedes aegypti mosquitoes. 

And subsequently, the number of people affected by mosquito-borne diseases has also increased.

Dengue fever is now considered the most critical mosquito-borne viral disease in the world, according to the World Health Organization. It’s also the most rapidly spreading, with a 30-fold increase in global incidence over the past 50 years.

Sri Lanka_Lab

How our Wolbachia method works

Our Wolbachia method is simple. 

We discovered that Wolbachia blocks viruses like dengue, chikungunya and Zika from growing in the bodies of Aedes aegypti mosquitoes. 

This means that Wolbachia mosquitoes have a reduced ability to transmit viruses to people.  

When Wolbachia is established in a mosquito population it results in a decreasing incidence of dengue, Zika, chikungunya.

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.

Our Wolbachia method can protect communities from mosquito-borne diseases without posing risk to natural ecosystems. Unlike most other initiatives, our method is natural and self-sustaining. 


WMP release mosquito

Wolbachia is one of the world’s most common types of bacteria, present in 50% of all insect species, including bees, beetles, butterflies, moths, and fruit flies. 

People are constantly exposed to Wolbachia through the foods they eat and the insects that bite them, but it causes no known health risks. It also does not affect the food chains of other species because Wolbachia does not reduce mosquito populations.

Independent risk assessments of WMP’s Wolbachia technology, undertaken in Colombia, Australia, Vietnam, and Indonesia concluded risk associated with release was negligible, low or acceptable.


Our method is unique and effective

Unlike most other techniques that aim to prevent mosquito-borne diseases, our Wolbachia method is natural and self-sustaining

Our method does not suppress mosquito populations or involve genetic modification (GM), as the genetic material of the mosquito is not altered. 

Long-term monitoring shows that our natural Wolbachia method is self-sustaining in almost all international project sites, with the first mosquitoes released in 2011.

Far-north Queensland is now essentially a dengue-free area for the first time in well over 100 years.
Dr Richard Gair
Director and Public Health Physician, Tropical Public Health Services, Cairns
Dr Richard Gair
Release Wolbachia mosquitoes

Once the project is understood and supported by the community, we breed Wolbachia mosquitoes.

Then, when we have enough, we release them.

This is a team effort! Lots of volunteers get involved for mosquito releases, including individuals, schools, universities and local community groups.

Because mosquitoes don’t fly very far, we usually release a handful of mosquitoes every 50 metres across the target area.

The release period usually lasts for 12 to 20 weeks.

Want to learn more about the World Mosquito Program and our sustainable and nature-based Wolbachia method?