GM mosquitoes are designed to prevent dengue fever

Genetically engineered mosquitoes are designed to stop the spread of dengue fever

07/11/2012

In the future, genetically modified mosquitoes in Brazil are intended to contain the population of the mosquito Aedes aegypti, as these cause dangerous dengue fever. If unchanged female mosquitoes mate with the genetically modified specimens, the common offspring dies already in the larval stage. However, the ecological consequences are not foreseeable. In Malaysia, a similar attempt was halted due to massive public protest.

So far no vaccine against dengue fever found
Dengue fever is an infectious disease caused by the dengue virus. The viruses are transmitted in tropical and subtropical regions by the mosquito "Aedes aegypti". Due to increasing globalization, experts are predicting that dengue fever will continue to spread due to the spread of its transmitter. The disease is the fastest-spreading and mosquito-borne viral infectious disease worldwide. So far, neither a vaccine nor a promising antiviral therapy could be developed.

Dengue fever is primarily characterized by flu-like symptoms such as fever, joint and limb pain. It can also cause internal bleeding and the so-called dengue shock syndrome (DSS), which in both cases leads to the death of the patient. Within the last six months, around 500,000 people in Brazil have contracted dengue fever.

Due to the increasing spread of the infectious disease, the Brazilian Ministry of Health plans to use genetically modified mosquitoes against the transmitter. Altered male mosquitoes are said to mate with unchanged dengue fever transmitting females. The common offspring should then die off already in the larval stage, so that the mosquito population is strongly contained.

Insect factory produces genetically modified mosquitoes against dengue fever
In the state of Bahia, the first insect factory of Oxitec, a spin-off of the University of Oxford, was opened a few days ago, which will in future produce around four million transgenic mosquitoes a week. Some time ago, Oxitec research chief Luke Alphey wrote in the journal „Nature Biotechnology“, that on the island of Grand Cayman in the Caribbean, there have already been successful field trials with the genetically modified mosquitoes. Further studies are cited by the Brazilian Ministry. In two villages, the mosquito population had declined by 90 percent within one year due to the genetically modified male mosquitoes.

However, the project of the Brazilian Ministry of Health is criticized in many places. The measure can only be considered a success after a long time. And only then, if the number of dengue infections actually go back, wrote the microbiologist Anthony James some time ago in the journal „Science“. The number of mosquitoes is only of minor importance, if the disease continues to spread and leads to the death of many people. The observation period of half a year is also too short to make reliable statements about the success of the experiment. The mosquito population could also have decreased within this short period of time due to other unknown influences.

Above all, critics worry about the ecological consequences that the intervention in nature could have. No one knows what consequences the ecosystem will face if the mosquito Aedes aegypti is eradicated. For example, it is the food source of many birds and other animals. The mosquitoes may also develop resistance, so that the offspring of the genetically modified animals survive. This could even promote a spread of dengue fever.

In Malaysia, the population prevented by massive protests the first field trials with the mosquitoes of Oxitec. The developer was later accused of informing the public too late and inadequately about his plans. (Ag)

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Picture: Depeche