Genetically modified mosquitoes are said to help fight diseases such as Zika and dengue fever in Florida. But residents are concerned.
Florida – Mosquitoes are insidious insects that are unlikely to have fans among humans. They disturb, sting and in the worst case also transmit diseases such as Zika, dengue fever or yellow fever. For this reason, the British biotechnology company Oxitec has declared war on them. Instead of insecticides, the company from Abington in the south-east of England relies on genetically modified insects to do the work.
As the journal Nature reports, the company has now exposed genetically modified mosquitoes for the first time in the USA. On the Florida Keys, a group of islands in southern Florida, genetically modified male mosquitoes of the Aedes aegypti species were released after years of conflict. These mosquitoes only make up around four percent of the mosquito population on the archipelago, but are virtually solely responsible for the transmission of all diseases that are transmitted by mosquitoes in the region.
Genetically modified mosquitoes are released in Florida
The male mosquitoes of this species do not bite, while the females can bite their victims and transmit diseases. The Oxitec team makes use of this fact: Male mosquitoes have been genetically modified in such a way that they carry a certain gene and pass it on to their offspring. This gene ensures that female mosquitoes die in the early larval stage, while male larvae develop into mosquitoes that carry the gene themselves and pass it on. The mosquito population is to be further reduced with each generation.
So far, Oxitec had carried out a field test on the largest of the Cayman Islands with the help of the “Bill and Melinda Gates Foundation”. Around 3.3 million modified male yellow fever mosquitoes were released there – around eleven weeks later the mosquito population had declined by around 80 percent. There have also been field tests in Brazil, Malaysia and Panama, in Brazil the mosquito population has been reduced by up to 96 percent, according to Oxitec. Now it’s the turn of the US state of Florida, which has seen an increase in mosquito-borne diseases since 2009.
Fight against disease: mosquitoes pass on certain genes – females die
The mosquitoes would become resistant to insecticides, which is why they are looking for new opportunities, said a responsible official at a press conference. The genetically modified mosquitoes are seen as an alternative to insecticides, which are widely used in the United States.
At the end of April, Oxitec researchers placed boxes with mosquito eggs in six locations in three areas on the Florida Keys, reports the journal Nature. To protect the controversial project, it was not disclosed where exactly the boxes were placed. In the first two weeks of May, the first male mosquitoes are expected to leave the boxes and mate with female mosquitoes; in the next twelve weeks, around 12,000 males should come out of the boxes per week. In a second phase, a total of 20 million mosquito males will fly out of the boxes over a period of 16 weeks. The plan is for the researchers accompanying the campaign to catch mosquitoes and examine them. In addition, it should be measured how far the mosquitoes are from the boxes and how long they live.
Mosquitoes in Florida: Local residents fear bites and worry about the ecosystem
Research is also interested in the question of whether all mosquito females with the modified gene die. The “Center for Food Safety” warned last year that not all of the female offspring could die and that hybrid mosquitoes with altered properties could develop. These mosquitoes could have “the potential for improved disease transmission or insecticide resistance,” the online portal Bloomberg Law quoted Jaydee Hanson from the “Center for Food Safety” as saying. After the mosquito field trial in Brazil, researchers found that some of the genetically modified mosquitoes had not only survived, but were apparently also able to reproduce and that traces of the genetic modification had been found in mosquitoes. However, the study itself is controversial.
There were and still are fears in Florida about the genetically modified mosquitoes. Residents would be afraid of bites or that the mosquitoes would disturb the ecosystem. “As you can imagine, the emotions boil up and there are people who are very strong for or against,” explains molecular biologist Natalie Kofler to Nature. Many of the concerns have to do with the fact that it is a new technology. Oxitec answers questions from the population on site, but many have no confidence because it is a company, says Kofler. (Tanja Banner)
