In the suburbs of Rio de Janeiro researchers from the Oswaldo Cruz Foundation, or Fiocruz, have started releasing tens of thousands of mosquitoes infected with a bacteria they say is the best defence against Dengue Fever.
For the program to work the mosquitoes will have to multiply, breed and become the majority of mosquitoes, reducing the incidents of the disease.
"In the short term, in about two years, we will see a reduction in Brazil yes, in the number of dengue cases in some places and then in something like five or even 10 years we will study an expansion of this project in Brazil with much more concrete data,” Fiocruz Researcher Luciano Moreira said.
“So, we have to do a study as if it were a clinical study that is much broader to really show a reduction in the number of cases of dengue in a satisfactory manner."
The intercellular bacteria, Wolbachia is found in about 60 percent of insects.
There is only one breed of mosquito which carries Dengue, Aedes Aegypti, and the vaccine acts like a vaccine, stopping the Dengue virus multiplying in its body.
The Wolbachia bacteria also effects reproduction. If a contaminated male fertilises eggs of a female without the bacteria, the eggs do not develop.
When the male and female are contaminated, or if only a female has the bacteria, all future generations of mosquito will carry Wolbachia.
The research on Wolbachia began at Australia’s Monash University Australia in 2008.
Professor Scott O'Neill from Monash University said it was the result of years of research efforts.
"It's a great day for the team you know it's been years of research that has got us to this point and it's great to see the mosquitoes set free," Professor O'Neill told SBS in Melbourne.
By 2011 researchers were releasing modified mosquitoes into the air in Cairns, where cases of Dengue Fever had been common.
“What we found in the these trials was that we could successfully deploy it (the bacteria) and over a period of about three months the number of mosquitoes in the wild population lifted up to 100 percent, fully infected with the Wolbachia bacteria and were preventing Dengue transmission,” Professor Scott O’Neill told SBS at the time.
Researchers allowed the mosquitoes to feed on their own arms for five years because of concerns at the time Wolbachia could infect humans and domestic animals.
Fiocruz representatives releasing the insects have told Brazilians that mosquitoes will continue exist as a pest but they will no longer represent a potentially lethal threat.
"We know the mosquitoes will not disappear, we will have the same quantity of mosquitoes here - but what do we want, what do we intend to do? The goal of Fiocruz is aligned with ours, which is to decrease the number of cases of dengue and to improve our health here," resident of Tubia Canga neighbourhood, Jose Cantisano said.
Releasing the mosquitoes is part of the international “Eliminate Dengue: Our Challenge” program which is being studied in Australia, Brazil, China, Colombia, Indonesia and Vietnam, all countries where the disease is prominent.
Professor O'Neill is confident the technique could become the best defense against dengue.
"This is the first of the study to be undertaken in Latin America and we are hoping it will get a foothold into Rio with this intervention and over the next couple of years scale it up and get direct measurements of efficacy against dengue disease," he said.
He also said his method offers a potentially cost effective way to combat dengue.
"For the people who have had it they can testify that it is a terrible illness to get so we desperately need new solutions. Currently nothing is really working. Brazil spends close to one billion US dollars a year on dengue control and it still has some of the highest case loads in the world."
But it is Brazil that the world will be watching. Dengue Fever re-emerged there in 1981 after 20 years without any cases detected.
Seven million cases were reported within the next 30 years making Brazil the world’s number one in Dengue Fever, an illness that has killed at least 800 people in the past five years.
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