Viruses, spread through mosquito bites, cause human illnesses such as dengue fever, Zika and yellow fever. A new control technique harnesses a naturally occurring bacterium called Wolbachia that blocks replication of viruses and breaks the cycle of mosquito-borne disease, according to an international team of researchers.
“Wolbachia is present in around 50 percent of all insects,” said Beth McGraw, professor and Huck Scholar in Entomology at Penn State, who did this research while at Monash University. “Interestingly it is not present in some of the major mosquito vectors (insects that transmit pathogens). After researchers put Wolbachia into mosquitoes, they found that, quite excitingly, Wolbachia effectively vaccinates mosquitoes, preventing viruses from replicating.”
Spread by Aedes aegypti mosquitoes, dengue virus affects millions of people each year. Symptoms include fever, body aches and nausea, although a more severe version, known as dengue hemorrhagic fever, can be fatal.
In the tropics and subtropics where Ae. aegypti resides, several large releases of Wolbachia are underway to test whether Wolbachia can reduce the incidence of human disease.
In a paper published recently in Virus Evolution, McGraw and her team report that dengue virus failed to evolve resistance to Wolbachia in controlled lab-based experiments. These findings show promise for the long-term efficacy of Wolbachia following field release.
“I am continually surprised by Wolbachia,” said McGraw. “I thought we would get dengue variants that would evolve resistance. Wolbachia is doing a better job than I expected at controlling virus replication in cells.”
The researchers took dengue virus and infected mosquito cells that either had Wolbachia or were free of bacteria. After five days, they collected the viruses that had been released from the cells and used them to infect fresh cells.
“Dengue takes over the machinery of the host cells, makes lots of copies of itself, and then it buds or burst out of the cell,” explained McGraw.
After nine rounds of passaging the virus through mosquito cells, the team found that the amount of virus released was stable in the Wolbachia-free cells. However, in the presence of Wolbachia, virus levels crashed — and in some cases, disappeared completely.
Dengue viruses grown with Wolbachia were also less effective at infecting mosquito cells and had reduced ability to replicate, compared to viruses grown without the bacterium.
Although this is good news for the control of dengue and other mosquito-transmitted diseases, the researchers note the study has limitations. The researchers used mosquito cells — which may not reflect what happens within the whole insect. And outside the lab, where mosquito populations are much larger, there may be more opportunities for the virus to develop resistance to Wolbachia.
“I think our study suggests that the evolution of resistance to Wolbachia in the virus is challenging,” said McGraw. “I don’t think it’s a guarantee that the virus is not going to evolve under field conditions because the natural system is much more complex. The real experiment is being done in the field right now, because Wolbachia has been released into communities in Australia, Indonesia and Brazil, among others. Monitoring in release areas will be needed to test for the emergence of resistance in the virus.”
The Latest on: Wolbachia
via Google News
The Latest on: Wolbachia
- Biological control proven effective on dengue in Selangoron November 5, 2019 at 4:14 pm
IN A bid to fight dengue, Aedes mosquitoes injected with the Wolbachia bacteria have been released at eight new areas in the Petaling district this year. This biological vector control management ...
- Wolbachia release program ends soonon October 23, 2019 at 5:00 pm
THE World Mosquito Program is expected to end its wolbachia release program in Lautoka and Nadi next month. Yesterday, organisers of the 20-week release program held a public awareness initiative in ...
- Too Hot to Handle: Loss of cytoplasmic incompatibility may hinder Wolbachia-centred disease controlon October 17, 2019 at 5:00 pm
Wolbachia bacteria are a genus of symbiotes that infect a wide range of insects. Transmitted through the female line, they are notable for their complicated effects on the reproductive capabilities of ...
- NEA to test releasing Wolbachia mosquitoes via droneon October 7, 2019 at 11:00 pm
This will involve the release of mosquitoes via drones, said the National Environment Agency (NEA) yesterday. Called Project Wolbachia, it is a programme where male mosquitoes carrying the Wolbachia ...
- NEA to test releasing mosquitoes via drone as Project Wolbachia moves to phase 4 of fight against dengueon October 7, 2019 at 9:07 am
Called Project Wolbachia, it is a programme where male mosquitoes carrying the Wolbachia bacterium mate with females, causing them to lay eggs that do not hatch. NEA has been studying the programme ...
- Wolbachia mosquitoes to be released in more neighbourhoods in Nee Soon and Tampineson October 7, 2019 at 1:07 am
SINGAPORE: Male Wolbachia-carrying mosquitoes will be released in more areas in Nee Soon East and Tampines West in November, as part of the next phase of a study to reduce the Aedes mosquito ...
- Indonesia's Wolbachia project holds big promise, raising hope for dengue eliminationon October 3, 2019 at 4:09 am
Since 2011 researchers have intervened in the environment by releasing Aedes aegypti mosquitoes carrying the Wolbachia bacteria in a residential area and have succeeded in drastically decreasing ...
- Bacteria-infected Brazilian mosquitoes pack a punch in dengue fighton October 2, 2019 at 6:52 pm
Scientists are using Wolbachia, a bacteria common among insects except the dengue-transmitting Aedes aegypti mosquito, to dent the spread of the debilitating virus and other illnesses including Zika ...
- Mosquito trials raise hopes of defeating dengueon September 11, 2019 at 12:05 pm
The World Mosquito Program (WMP) has pioneered a method where male and female Aedes Aegypti mosquitoes are infected with the disease-resistant bacteria called Wolbachia before being released into the ...
- Bacteria v mozzies. Bacteria holding their ownon August 26, 2019 at 2:30 pm
The researchers also identified a gene that could explain how the bacteria disrupts the spread of disease. Wolbachia bacteria live inside many insect cells, but not in A. aegypti. Because of their ...
via Bing News