You should be excited that scientists are releasing 750 million genetically modified mosquitoes this year

L. Westreich,  Massive Science,  2020.

Mosquito-borne diseases include malaria, yellow fever, and the Zika virus – all of which can cause extreme sickness, birth defects, or death. Per year, malaria is responsible for the deaths of over 400,000 people, while dengue fever causes about 20,000, according to the World Health Organization.

Vaccines have been in development for dengue fever, malaria, and Zika, but production can be very slow and result in low efficacy. Drugs can help, but can be expensive. Insecticides are successful in the short term, but mosquitoes can become resistant, and mass-release insecticide can have health impacts on plants and wildlife.

Instead, others have focused their attention on treating the mosquitos, not the symptoms: genetically modifying mosquitos themselves to only produce sterile offspring, effectively wiping out an entire population of insects. Modern genetic modification techniques are fast, and work at the scale of genes – but they mimic the plant breeding focused on phenotype humans have been doing since the beginning of history (like, say, selective breeding of crops, which humans have been doing since agriculture was invented).

GM mosquitoes are successful in reducing mosquito populations, and reducing disease spread

There are two general approaches to producing genetically modified mosquitoes: 1) modifying the reproductive ability of male mosquitoes so that they cannot produce offspring, and 2) modifying both male and female mosquitoes so that they are resistant to diseases or incapable of transmitting them to other species. Oxitec, the biotechnology company behind a genetically modified (GM) mosquito Aedes aegypti, has tested the first approach to GM mosquito releases in field trials in parts of Brazil, the Cayman Islands, and Malaysia. These male mosquitoes mate with a female, exchanging a gene mutation that causes the larvae to die unless they are given an antibiotic. These trials have shown to reduce mosquito populations from 80-95%, reducing dengue fever cases by 91%.

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