Illustrative photo (Source: thanhnien.vn)KhanhHoa (VNA) - The Ministry of Health will release 1 million to 1.4million of Wolbachia-infected mosquitoes in four wards in Nha Trang city, thecentral province of Khanh Hoa in an effort to reduce the number of incidencesof dengue fever and Zika virus infections.
About 56,000 people livein the wards, which include Vinh Phuoc, Vinh Tho, Vinh Truong and Phuoc Long.
Wolbachia is a bacterium that exists in up to 60 percent of different speciesof insects, but not in the dengue and Zika-carrying mosquito Aedes aegypti.
Scientists have transferred Wolbachia from the fruit fly to Aedes aegyptimosquitoes to reduce the ability of mosquitoes to transmit dengue and Zikaviruses.
After the initial release of several weeks, mosquitoes with a Wolbachiabacterium are expected to mate with wild mosquitoes without Wolbachia.
When male mosquitoes with the Wolbachia bacterium mate with female mosquitoes,the females develop eggs, but they won’t hatch. If the females already carryWolbachia, all the offspring will have Wolbachia.
When female mosquitoes with the Wolbachia bacterium mate with males withoutWolbachia, all her offspring will have Wolbachia.
As the bacteria are passed on from generation to generation and over time, thepercentage of mosquitoes carrying Wolbachia grows until it remains high withoutany need for further release.
After three months of releasing Wolbachia-infected mosquitoes, the number ofthe mosquitoes at the four localities is expected to reach 70 percent of thetotal mosquito population.
In March last year, the World Health Organisation recommended pilot deploymentsof the Eliminate Dengue Programme approach, which introduces Wolbachia intomosquito populations to prevent transmission of Aedes aegyot- transmitted viruses as an alternative to mosquito populationsuppression.
Le Tan Phung, deputy head of Khanh Hoa province’s Department of Health, saidthe provincial People’s Committee has not yet decided the time to release theWolbachia-infected mosquitoes in the four wards.
The committee is now instructing agencies to collect opinions about the releaseto people in the wards.
The first trial site for release of Wolbachia-infected mosquitoes was on TriNguyen Island in Khanh Hoa province in 2013 under the Eliminate Dengue Vietnam programme, monitored by the Ministry of Health. The release was completed in2014.
Around 100 percent of the mosquitoes in the area are now carrying Wolbachia,according to a press release published on the website of the Eliminate Dengue Vietnamprogramme.
Thanks to the programme, only one person was infected with dengue fever on theisland in 2015. As of the end of last year, there were no cases of denguefever, but cases still occurred in Nha Trang.
The programme is conducted by Australia’s Monash University under thesponsorship of the Foundation for the National Institutes of Health through theBill & Melinda Gates Foundation’s Grand Challenges in Global HealthInitiative.
Begun in 2005, the programme has been carried out in Australia, Brazil, China,Indonesia and Vietnam.
Research published in Scientific Reports journal in July 2016 showed moreevidence that Wolbachia blocked transmission of the Zika virus.
The research was conducted by scientists from the University ofWisconsin-Madison and the Universidad de Antioquia.
“We found that mosquitoes carrying Wolbachia were less likely to becomeinfected with Zika virus after feeding on viral blood, and those that wereinfected were not able to transmit the virus through their saliva,” said JorgeOsorio, professor at the University of Wisconsin, one of the authors of thereport.
In the Eliminate Dengue Vietnam programme, 23,682 Aedes aegypti mosquitoes were collected and stored inNha Trang from March 2015 to May 2016.
Of these, 56 tested positive for Zika virus and 29 positive for dengue virus.
As of November last year, the province had recorded two patients positive forZika virus and 4,454 patients infected with dengue fever.
Nha Trang city and Ninh Hoa town had the highest number of dengue feverpatients.-VNA
About 56,000 people livein the wards, which include Vinh Phuoc, Vinh Tho, Vinh Truong and Phuoc Long.
Wolbachia is a bacterium that exists in up to 60 percent of different speciesof insects, but not in the dengue and Zika-carrying mosquito Aedes aegypti.
Scientists have transferred Wolbachia from the fruit fly to Aedes aegyptimosquitoes to reduce the ability of mosquitoes to transmit dengue and Zikaviruses.
After the initial release of several weeks, mosquitoes with a Wolbachiabacterium are expected to mate with wild mosquitoes without Wolbachia.
When male mosquitoes with the Wolbachia bacterium mate with female mosquitoes,the females develop eggs, but they won’t hatch. If the females already carryWolbachia, all the offspring will have Wolbachia.
When female mosquitoes with the Wolbachia bacterium mate with males withoutWolbachia, all her offspring will have Wolbachia.
As the bacteria are passed on from generation to generation and over time, thepercentage of mosquitoes carrying Wolbachia grows until it remains high withoutany need for further release.
After three months of releasing Wolbachia-infected mosquitoes, the number ofthe mosquitoes at the four localities is expected to reach 70 percent of thetotal mosquito population.
In March last year, the World Health Organisation recommended pilot deploymentsof the Eliminate Dengue Programme approach, which introduces Wolbachia intomosquito populations to prevent transmission of Aedes aegyot- transmitted viruses as an alternative to mosquito populationsuppression.
Le Tan Phung, deputy head of Khanh Hoa province’s Department of Health, saidthe provincial People’s Committee has not yet decided the time to release theWolbachia-infected mosquitoes in the four wards.
The committee is now instructing agencies to collect opinions about the releaseto people in the wards.
The first trial site for release of Wolbachia-infected mosquitoes was on TriNguyen Island in Khanh Hoa province in 2013 under the Eliminate Dengue Vietnam programme, monitored by the Ministry of Health. The release was completed in2014.
Around 100 percent of the mosquitoes in the area are now carrying Wolbachia,according to a press release published on the website of the Eliminate Dengue Vietnamprogramme.
Thanks to the programme, only one person was infected with dengue fever on theisland in 2015. As of the end of last year, there were no cases of denguefever, but cases still occurred in Nha Trang.
The programme is conducted by Australia’s Monash University under thesponsorship of the Foundation for the National Institutes of Health through theBill & Melinda Gates Foundation’s Grand Challenges in Global HealthInitiative.
Begun in 2005, the programme has been carried out in Australia, Brazil, China,Indonesia and Vietnam.
Research published in Scientific Reports journal in July 2016 showed moreevidence that Wolbachia blocked transmission of the Zika virus.
The research was conducted by scientists from the University ofWisconsin-Madison and the Universidad de Antioquia.
“We found that mosquitoes carrying Wolbachia were less likely to becomeinfected with Zika virus after feeding on viral blood, and those that wereinfected were not able to transmit the virus through their saliva,” said JorgeOsorio, professor at the University of Wisconsin, one of the authors of thereport.
In the Eliminate Dengue Vietnam programme, 23,682 Aedes aegypti mosquitoes were collected and stored inNha Trang from March 2015 to May 2016.
Of these, 56 tested positive for Zika virus and 29 positive for dengue virus.
As of November last year, the province had recorded two patients positive forZika virus and 4,454 patients infected with dengue fever.
Nha Trang city and Ninh Hoa town had the highest number of dengue feverpatients.-VNA
VNA
