Dengue Fever Cases Drop 91% in Neighbourhood of Piracicaba, Brazil, Where Oxitec’s Friendly™ Aedes Were Released


Epidemiological surveillance year ended in July 2016 with 12 cases reported for the disease in CECAP/Eldorado, compared to 133 in the year that preceded it

OXFORD, England, July 14, 2016 /PRNewswire/ — Piracicaba’s Epidemiologic Surveillance service released new data this week which showed a 91% reduction of dengue fever cases registered in the CECAP/Eldorado district, an area of 5,000 residents, in the 2015/2016 dengue-year as compared to the 2014/2015 period. The incidence decreased to just 12 cases in 2015/2016, the first year in which Friendly Aedes, the genetically engineered mosquitoes that fight wild Aedes aegypti, were released there, versus 133 cases in the previous year. According to Epidemiologic Surveillance the rest of the municipality saw a 52% reduction in dengue fever incidence during the same period, from 3,487 cases in the 2014/2015 period to 1,676 cases in 2015/2016.

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Additionally, the overall incidence rate in CECAP/Eldorado for the dengue-year 2014/2015 was 195% larger than the rate recorded for the rest of the municipality. In the dengue-year 2015/2016, the rate in CECAP/Eldorado was 45% lower than the rate in the rest of the municipality. The latest data roundup also reports zero cases of Zika and chikungunya in CECAP/Eldorado.


Dengue Year**




Cases of Dengue










Cases of Dengue









* Data excludes CECAP/Eldorado

** Dengue year in Brazil starts in 27th week of the calendar year and ends in 26th week of following calendar year

“Over the course of one year, we were able to bring the dengue fever incidence down by more than 50% in Piracicaba — the outcome of diligent work to eliminate still water spots, the breeding site of the mosquito,” says the city’s Secretary of Health, Pedro Mello. “In CECAP/Eldorado, where we had the Friendly Aedes project, the reduction was extraordinary, going over 90%.”

“We are delighted with the result achieved so far by Friendly Aedes which shows the potential of our approach. We hope to see this effect on a larger scale beyond the limited area of CECAP/Eldorado with our expansion into Piracicaba’s downtown city,” says Glen Slade, Oxitec do Brasil director.


The dengue-year in Brazil starts in the 27th week of the calendar year and ends in the 26th week of the following year. This period is used by health surveillance services as a standard for monitoring and reporting epidemiological data of diseases transmitted by Aedes aegypti. The incidence rate for a disease in a certain area is an important element in planning the fight against the disease.

Friendly Aedes

Produced by Oxitec do Brasil, Friendly Aedes have been used in Piracicaba since April 30th 2015, when the first insects were released in CECAP/Eldorado. In January 2016, the technology had already reduced the number of wild Aedes aegyptilarvae by 82% in the treated area, compared to a non-treated area.

The success in reducing the population of wild Aedes aegypti led the City Hall to extend the project at CECAP/Eldorado for one more year. The deployment of Friendly Aedes was expanded into the city’s downtown area, comprising an area of 11 neighbourhoods and 60,000 residents. The first Friendly Aedes to be deployed in the downtown area are expected to be released in the São Judas neighbourhood by the second half of July. A contract for the expansion of the FriendlyAedes project into the downtown area was signed on May 31st. Besides São Judas, the project is intended to benefit São Dimas, Centro, Clube de Campo, Cidade Jardim, Cidade Alta, Parque da Rua do Porto, Nhô Quim, Jardim Monumento, Nova Piracicaba and Vila Rezende.

How Friendly Aedes works

Oxitec has been working in Aedes aegypti control for more than a decade. It is a pioneer in the use of a biological method to suppress wild populations of this dangerous mosquito species through the release of Friendly Aedes males, which don’t bite and don’t transmit disease. When released, these males search for wild females to mate, and their offspring inherit a self-limiting gene that makes them die before reaching functional adulthood. Friendly Aedes’ offspring also inherit a fluorescent marker that makes them easy to identify in the laboratory. This allows tracking and measuring at a level never before achieved, making effectiveness assessment and monitoring more accurate throughout the whole Friendly Aedes deployment programme.

Unlike other approaches, Friendly Aedes mosquitoes don’t leave any ecological footprint. Friendly Aedes die along with their offspring, so that their presence doesn’t linger in the environment.

About Oxitec

Oxitec is a pioneer in using genetic engineering to control insect pests that spread disease and damage crops, and was founded in 2002 as a spinout from Oxford University (UK). Oxitec is a subsidiary of Intrexon Corporation (NYSE: XON), which engineers biology to help solve some of the world’s biggest problems. Follow us on Twitter at @Oxitec.

Oxitec Contact:

Matthew Warren
Press Officer
[email protected]