The Brazilian city of Piracicaba has become the host of the first large-scale trial of a new technique to control the mosquito that transmits diseases such as dengue, chikungunya or Zika. The weapon developed by a British biotechnology company is the “Friendly Aedes aegypti” mosquito (technically called OX513A), a new engineered strain or variant of the Aedes aegypti mosquito.
The Friendly Aedes aegypti is a genetically modified male mosquito that cannot bite or transmit disease. When it mates with a local female Aedes aegypti mosquito, the offspring die before being able to reproduce, reducing the mosquito’s population.
Currently, there are a dozen of scientific projects of genetically modified insects (transgenic) in various parts of the world; however, the massive release of Friendly Aedes aegypti mosquitoes in Piracicaba is the first large-scale trial in the world. The project estimates that in two years, more than 100 million transgenic mosquitoes will be released into the Brazilian city of 400,000 inhabitants.
The first stage of the program for releasing transgenic mosquitoes was launched in the Piracicaba’s district of CECAP/Eldorado, in Piracicaba (Brazil) on April 30th 2015. This stage consisted of releasing about seven million mosquitoes in a prolonged period of time. Because both transgenic mosquitoes and their descendants have an average life of only four days, the release process has been carried out gradually, so that the impact on the overall mosquito population is greater and more persistent.
After a proven success in CECAP/Eldorado district, a second stage was launched in São Judas neighborhood last March, to release a total of 30 million Friendly Aedes aegypti.
On September 6 also Oxitec, the company that develop the transgenic mosquitoes , and the Piracicaba’s authorities confirmed that 10 more districts will continue the program (Centro, Cidade Alta, Cidade Jardim, Clube de Campo, Jardim Monumento, Nova Piracicaba, Nhô Quim, Parque da Rua do Porto, São Dimas y Vila Rezende).
The main study, conducted before authorizing project for releasing transgenic mosquitoes in Brazil, was presented in April 2014 by the National Biosafety Commission of Brazil (CNBB). This commission of experts concluded that the mosquito developed by Oxitec (OX513A) “does not present no new biologic risk to humans or the environment, so its release in the environment could be authorized,” according with an article published last August in the Bulletin of the World Health Organization.
Following the report of this committee, “Brazil became the first country to authorize the massive release of genetically modified mosquitoes,” said the article signed by Professor Paulo Paes de Andrade and twelve other Brazilian scientists.
The opposing views
Although so far there is a vast majority of studies indicating that the controlled release of such transgenic mosquitoes will no cause health or environmental risks in, some scientists and environmental organizations have shown their opposition, arguing that do not exist enough studies to ensure the safety and effectiveness of this initiative.
“There was a very large pressure for a quickly release, though at the time there were not enough studies,” said José Maria Gusman Ferraz, member of the National Biosafety Commission of Brazil.
In comments reported by BBC World, the biologist Gusman Ferraz, who studied the first project for the release of modified mosquitoes said that, “there was a very large pressure quickly released it, though at the time there were not enough studies to say that it has no risks.”
Sociedade to Defesa do Meio Ambiente de Piracicaba (Brazil) issued in April 2015 a public letter of complaint and demanded stopping the release og genetically modified mosquitoes.
Reduction of dengue in Brazil
In July this year, the service Epidemiological Surveillance of Piracicaba (Brazil) reported the results of a study indicating that in CECAP/Eldorado, an area of about 5,000 residents where the first release of genetically modified mosquitoes Friendly Aedes were conducted, the dengue epidemic has been reduced from 133 cases in the 2014-2015 period to only 12 cases in the 2015/2016 period, i.e. a reduction of 91 percent.
According Epidemiological Surveillance in the rest of the municipality of Piracicaba —where there was no tested the new variant of the mosquito but other sanitary control measures were practiced— the reduction of dengue cases was 52% (of 3,487 cases in the 2014/2015 period to 1,676 cases in the 2015/2016 period).
Trials around the world
OX513A mosquitoes contain a fluorescent marker called DsRed, which facilitates their identification in the laboratory, to monitoring their expansion.
Oxitec has conducted various tests with OX513A mosquito in laboratories in France and Malaysia; and five field trials in Brazil, Panama and the Cayman Islands. Tests have shown that releases of these self-limiting mosquitoes reduced by up to 90 percent of the wild population of Aedes aegypti, according to Oxitec.
The company says it has permission to carry out new applications with this type of mosquito in Brazil, Cayman Islands, France, India, Malaysia, Singapore, Thailand, Florida (US) and Vietnam.
Source: Agencia ID
