Dengue: transgenic mosquito is sold amid imbroglio – 04/21/2023 – Science

a mosquito aedes aegypti genetically modified to control diseases such as dengue fever is the subject of a judicial imbroglio. The court’s decision authorizes the product, but Anvisa, one of the parties involved in the process, appealed the decision and is awaiting a new trial at the second instance.

The modified mosquito is the flagship of Oxitec, a British company with a branch in Brazil. Two genes were chosen to be altered in the manufacturer’s mosquito version.

The first of these is tTAV. In its normal state, the gene makes a small amount of a protein. But a large-scale production of this substance caused by genetic alteration leads to female death. “The females overproduce this protein and, in larval life, they collapse”, summarizes Luciana Medeiros, coordinator of field operations for health programs at Oxitec and doctor in functional and molecular biology.

And the purpose of the alteration is exactly this: that the females die due to the modification, because only they bite humans and transmit diseases, in addition to suppressing the insect population. The second change is fluorescence. The change was basically made to track the mosquito once it was released into the field for research purposes.

Commercially called Aedes do Bem, the product boxes are sold in two versions: a smaller one, at an average cost of R$ 249, with the possibility of being ordered over the internet by anyone who lives in the state of São Paulo or purchased in stores. partners. The other, larger size, is exclusive to companies and governments.

With the box in hand, the person adds water and, after a few days, the transgenic male mosquitoes will come out into the environment. The aim is for them to mate with wild females.

The descendants will all be males, considering that the new generation will have the alteration that is fatal to females. Therefore, it is expected that the number of females will decrease in the environment, also causing a drop in the transmission of diseases such as dengue.

This process ends up in up to ten subsequent generations of mosquitoes, because the descendants share the genetic material of the wild female, which does not have the modification.

Oxitec carried out studies in Brazilian cities, such as Jacobina, in Bahia, and Indaiatuba, in São Paulo, to measure the effectiveness of the technology. It also maintains a partnership with companies, such as Socicam, which manages the Tietê Bus Terminal, in the north of São Paulo, where 15 boxes of the modified mosquito were spread.

Data from the studies were used in the analysis that attested to the biosafety of mosquitoes. Even so, the product is subject to criticism.

José Maria Gusman, professor at Uniara (University of Araraquara), was one of the technicians who evaluated the first version of the insect, which has already been discontinued by Oxitec.

In his opinion, more studies were needed before the release of the technology. One of the points of concern for the professor is tetracycline, which works as an antidote for transgenic females.

By having contact with this substance, this female does not die in the larval stage, which could have the opposite effect on the environment: instead of decreasing the number of mosquitoes, it would increase.

Gusman points out that tetracycline is used in feed production. So, in certain places, transgenic females could stay alive.

Medeiros says, however, that Oxitec carried out surveys and observed that there is not enough tetracycline in the environment to keep the transgenic females alive.

Agronomist Leonardo Melgarejo, collaborator of the National Articulation of Agroecology, is another who has reservations about the modified mosquito.

He was also one of the experts who evaluated the technology and points out that the volume of modified mosquitoes in the environment would need to be very high to possibly have a positive effect.

“It would take an exorbitant amount [de mosquitos transgênicos] to work at a certain time, because there will be a permanent migration of wild mosquitoes from other areas to this location.”

The point is also hit by Medeiros. She explains that, during the years of research, it was concluded that it is necessary to have at least five modified mosquitoes for each wild one in order to maintain the suppression of the insects. The proportion would be achieved considering the number of insects expelled in the boxes sold by the company.

Court proceedings

The product developed by Oxitec is classified as a genetically modified organism — known by the acronym GMO. The procedure for releasing this type of product requires an authorization from the CTNBio (National Technical Commission on Biosafety), which was given for both versions of the manufacturer’s mosquitoes.

On the other hand, the commercial registration and inspection of a GMO is the duty of another entity that varies depending on the type of organism. One of these is Anvisa, which “intended to regulate the registration of this type of technology as a sanitizing agent with a view to its disinfectant action”.

Two other authorities responsible for registering and inspecting GMOs, Ibama and the Ministry of Agriculture, told the report that they did not carry out the registration and inspection of the modified mosquito because it falls within the scope of Anvisa.

In a report published in 2018 in this Sheetit is reported that Oxitec was waiting for the agency’s registration for the first version of the modified mosquito after CTNBio’s assent, but the company filed a lawsuit against Anvisa.

The thesis was that the agency did not have the competence to regulate the product, and the Justice decision was in favor of suspending the procedures of the product at Anvisa.

The point was criticized by the then director-president of Anvisa at the time, Jarbas Barbosa. He stated in the 2018 report that the agency “cannot give a record based on the assessment of any other body”.

The entity appealed and, in the most recent decision, dated 2019, the judge assessed that Anvisa does not have the capacity to regulate the mosquito. Again, the agency appealed the decision and awaits judgment in the second instance.

The whole process was about the first generation of the mosquito, which is discontinued. However, Anvisa said that the Justice’s understanding also includes the product that is now marketed.

In a note sent to Sheet, Oxitec stated that CTNBio’s assent is sufficient for the commercialization of the transgenic mosquito. “The regularization of Aedes do Bem occurred completely and formally, under the terms of the law and through the only Brazilian public authority responsible for the release of GMOs, CTNBio.”

For the company, the Court’s decision is an indication that CTNBio’s authorization is enough to release the product. In the sentence, the judge considered Anvisa incompetent to regulate or commercially release the mosquito and mentioned that the product, according to the opinion of the biosafety commission, does not pose risks to human health or the environment.

Another party heard by the report was CTNBio itself. In a note, the MCTI (Ministry of Science, Technology and Innovation), the body to which the commission is linked, clarified that “CTNBio is not responsible for authorizing or inspecting the product. These procedures are the responsibility of the National Health Surveillance Agency (Anvisa) ). We also communicate that the product can be sold in accordance with the rules defined by the agency”.

Another point mentioned by Oxitec is that the Public Ministry would be a government agency that “can (as it does) accompany, monitor and supervise” Aedes do Bem. A Sheet contacted the Federal Public Prosecutor’s Office and that of the State of São Paulo. The first said he did not intervene in the lawsuit brought by Oxitec against Anvisa because the “action does not conform to the constitutional role of the Public Ministry”. The second did not respond to the report.