How it works
When Aedes aegypti mosquitoes carry natural bacteria called Wolbachia, they’re less able to transmit viruses like dengue, Zika, chikungunya and yellow fever.
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.
Aedes aegypti mosquitoes originated in Africa, but have spread through tropical and subtropical regions around the world. They first spread outside Africa during the slave trade between the 15th and 19th centuries, then through trade with Asia during the 18th and 19th centuries, and again following troop movements in World War II.
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 – and the number of people affected by mosquito-borne diseases has grown with it.
Dengue 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.
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
We discovered that Wolbachia blocks viruses like dengue, chikungunya and Zika from growing in the bodies of Aedes aegypti mosquitoes. This means 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 and chikungunya. So we breed Wolbachia mosquitoes and, in partnership with local communities, release them into areas affected by mosquito-borne diseases.
Our method can protect communities without posing risk to natural ecosystems. Unlike most other initiatives, it is natural and self-sustaining.
Is it safe?
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 the 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. It does not suppress mosquito populations or involve genetic modification, as the genetic material of the mosquito is not altered.
Long-term monitoring shows that our 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.
How we release Wolbachia mosquitoes
Together with communities around the world, we’ve released Wolbachia mosquitoes into many towns and cities. We started our first trials in Australia and, once we proved the method could work, began small trials around the world. We always work with the approval of the communities affected.
- Partner locally. We work closely with local governments, health authorities and community groups before we release any mosquitoes.
- Share the plan. We spread the word through local events, TV, radio, newspapers, social media and word of mouth.
- Check support. We survey the community to make sure there’s support for the project to go ahead.
- Breed. Once the project is understood and supported, we breed Wolbachia mosquitoes.
- Release. Volunteers – individuals, schools, universities and community groups – help release a handful of mosquitoes about every 50 metres across the target area, usually over 12 to 20 weeks.
How do we know it works?
We monitor both the Wolbachia mosquito population and the incidence of disease before, during and after releases. We have strong evidence showing the effectiveness and safety of our method.
We have set up projects in 15 countries, and our Wolbachia mosquitoes have protected more than 16 million people (May 2026). In areas where Wolbachia is self-sustaining at a high level, dengue transmission has been significantly reduced.