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1. What is Wolbachia?
Wolbachia are bacteria that only live inside insect cells. This bacterium occurs naturally in up to 60 per cent of all insect species, including butterflies, dragonflies and moths, as well as many mosquito species that bite people but do not transmit the disease. Despite the broad range of insects carrying Wolbachia, it is not infectious and cannot be transmitted to any warm blooded animals, including humans.
2. What effect will Wolbachia have on mosquitoes carrying dengue?
Wolbachia will reduce the ability of insects to become infected with viruses, including the dengue virus. If mosquitoes cannot become infected with dengue, they cannot transmit the virus between people.
3. How will Wolbachia spread through the mosquito population?
Wolbachia can only be transmitted from parent to offspring inside the female’s egg. It spreads into insect populations by altering the reproductive success of the insect that carries it.
When a male mosquito that carries Wolbachia mates with a female without the bacteria then that female’s eggs don’t hatch. Wolbachia infected female mosquitoes do not suffer from this effect and produce normal numbers of offspring – which carry Wolbachia. Initially, this reproductive effect will be very small as there will be few Wolbachia infected mosquitoes in the population, but over successive generations the numbers of males and female mosquitoes infected with Wolbachia will increase.
4. How safe is Wolbachia?
The Eliminate Dengue program has demonstrated that Wolbachia is safe by allowing the mosquitoes to feed directly from researchers on a routine basis. Wolbachia cannot be passed to humans as it is too big to travel down the salivary gland ducts of a mosquito.
5. Will the bite of a mosquito infected with Wolbachia hurt more than a normal bite?
No, people who are bitten by an Aedes aegypti mosquito containing Wolbachia will not notice any difference or be harmed in any way.
6. Is Wolbachia harmful to the environment?
No, Wolbachia is a naturally occurring bacterium that is already found in the environment in up to 60 per cent of all insect species, including many mosquitoes that bite people.
7. Can Wolbachia be passed to people?
Wolbachia cannot be passed from mosquitoes to people, as the Wolbachia is too big to travel down the salivary gland duct of a mosquito when it bites. Many mosquito species naturally have Wolbachia, and these mosquitoes commonly bite people without any adverse effects.
8. Do other animals carry Wolbachia?
Wolbachia is common among arthropods (including insects, spiders and other small animals with no backbone). Up to 60% of insect species naturally carry Wolbachia, including butterflies, dragonflies, moths and some mosquito species, but not the primary species of mosquito involved in the transmission of dengue.
Wolbachia is also found in certain types of roundworms – known as nematodes – but this is very different to the insect Wolbachia that we work with. Wolbachia is not found in any larger animals such as mammals, reptiles, birds and fish.
9. What type of Wolbachia do you work with?
Wolbachia refers to a whole genus of bacteria, of which there are many different types and strains. We work with several strains of insect Wolbachia, including wMel and wMelPop. The type of Wolbachia we work with exists only within insect cells and has no link to illnesses such as river blindness.
10. Are mosquitoes which carry Wolbachia more likely to transmit other diseases?
Research shows that Wolbachia does not increase the risk of other pathogens being transmitted by Aedes aegypti mosquitoes. In fact, although our main focus is on reducing dengue transmission, the Wolbachia method has also been shown to reduce transmission of other viruses including Zika, chikungunya and yellow fever.
11. Does heat stress impact the effectiveness of Wolbachia to invade mosquito populations?