TECHNICAL NOTE FROM CTNBio'S PRESIDENT AND VICE PRESIDENT (National Technical
Commission of Biosafety) regarding the recently published article in Scientific Reports entitled:
Transgenic Aedes aegypti Mosquitoes Transfer Genes into a Natural Population, Evans et
al. Scientific Reports, Vol 9, Article number: 13047 (2019).

CTNBio is a technical and scientific Commission created by the Brazilian Biosafety Law 11.105,
in March 23, 2005. The CTNBio is composed by 54 scientist bearing PhD title, and meets 10
times a year in Brasilia in order to analyze, on a case by case basis, the safety of genetically
modified organisms for human and animal health, plants and the environment. The process is
robust and transparent, so that documents used in the analysis and all the decisions are
published in CTNBio's homepage (http://www.ctnbio.mctic.gov.br).
CTNBio analyzes projects in contention, the planned releases in the environment and the
commercial releases of GMO.
After the analysis of the article in Scientific Reports entitled: Transgenic Aedes aegypti
Mosquitoes Transfer Genes into a Natural Population, Evans et al. Scientific Reports, Vol 9,
Article number: 13047 (2019) by members of the CTNBio, population genetics specialists and
technology developers from universities and companies, with the objective of controlling
disease-causing vectors of high relevance to Brazilian Public Health, CTNBio raises the following
considerations in relation to the above mentioned Article published in a renowned international
journal in the scientific area.

1. From the methodological point of view the authors used a very robust, high
performance SNPs array with number of markers and appropriate analysis, as well as
gene introgression in mosquito populations;

2. The genetic background of the Oxitec's strain OX513A originated from the crossing of
two other highly susceptible to insecticides strains from Cuba and Mexico, precisely to
minimize its persistence in the environment. The Brazilian strains do not present high
sensitivity to insecticides, due to the long-term use of chemical agents to control the
mosquito that transmits diseases of high relevance to the Public Health;

3. It is important to emphasize that the authors of the Article did not showed any data
concerning SNPs markers for the male-sterile self-limiting gene expression cassette, a
strategy used to develop this OGM; therefore, there is no experimental support to they
can claim that the transgene (expression cassette) was transferred to the natural
population. The title of the article is completely misleading. It has not been shown in
the results that the transgene was transferred to the natural population.

4. Figure 2C clearly shows that the number of hybrid individuals declines strongly over time
(27-30 months), which indicates that the hybrids do not have an increased adaptive
capacity, and thus do not remain in the environment, which testifies against the
hypothesis raised in the article around the "hybrid vigor". These hybrids are unable to
compete with the local strain, or at least are being deprecated in terms of mating;

5. The authors themselves, at the end of the topic Results, report that they have done
infectivity tests for dengue and Zika virus on the OX513A strain and in the natural
mosquito population in Jacobina (BA). The results indicated that there was no significant
difference between the two mosquito populations;

6. The Discussion topic of this article raises speculative questions that go against the
results presented by the article itself. Speculating about "hybrid vigor" when the article
itself demonstrates a strong decrease in their frequency, and probably the
disappearance of hybrid mosquitoes after 36 months? This requires experiments for
reliable information;

7. According to one of the authors, Dr. Margareth Capurro, in personal communication,
the genetic background was also monitored during this study. The authors measured
two parameters, (1) the genetic construction itself, which disappears from the
mosquitoes population in 2 weeks and (2) the natural genetic backgrounds found in the
environment during treatment of the area. The results demonstrate that the hybrid is
weak and not strong and disappears with time. It is hard to understand why so
important data were hiding.

8. In summary, the data do not point to the maintenance of the self-limiting gene of the
OX513A strain that produced the hybrid mosquito in the environment. The company
Oxitec has been monitoring releases in the environment and is on CTNBio's agenda the
Final Report on Post-Release Monitoring, CTNBio Process n. 01200.002919 / 2013-77,
which is scheduled as a matter of urgency for analysis in the next regular meeting of the
CTNBio Commission on October 2nd and 3rd. If necessary, Oxitec will be asked to proceed
with additional monitoring and follow-up during the research, as well as any other
appropriate measures.

We are hereby contacting the Editors of the Scientific Reports journal to clarify the rigorous
criteria used by CTNBio, based on scientific data and experiments, which guide all the technicalscientific decisions made by this Biosafety Committee in Brazil.
Finally, it is important to highlight that all experimental work and commercial use of this
technology, which is on the frontier of knowledge in Brazil and in the world and, implies in risks
and uncertainties is under a permanent analysis and surveillance by CTNBio with total
transparence with the facts. This is what CTNBio has always done and will continue to do in order
to make its decisions.
Sincerely,

Maria Sueli Felipe
CTNBio President

Maria Lucia Zaidan Dagli
CTNBio Vice President