Scientists at the University of California say they’ve created a new strain of mosquito that could help wipe out malaria. It’s an interesting development, as mosquitoes are known for spreading the disease. But is it safe?
In recent years, scientists have edited bacteria within mosquitoes in an effort to kill the malaria they carried. The newest malaria-fighting insects have been genetically modified, however.
The researchers used a gene-editing technique called CRISPR to insert DNA into the germ line of the Anopheles stephensi mosquito. In a statement on the school’s website, the team said they discovered that the gene halted the transmission of the disease through 99.5% of the pests’ offspring. 
“This opens up the real promise that this technique can be adapted for eliminating malaria,” said Anthony James, Distinguished Professor of molecular biology & biochemistry and microbiology and molecular genetics at UC’s Irvine campus.
“We know the gene works. The mosquitoes we created are not the final brand, but we know this technology allows us to efficiently create large populations,” James said.
Malaria, while deadly, is a preventable and curable disease caused by the Plasmodium parasites. According to the World Health Organization (WHO), of the 5 species that cause malaria in humans, P. falciparum and P. vivax are the most deadly.
The genetically engineered mosquitoes carry extra genes for antibodies that block the development of the Plasmodium parasite within the insect, thus preventing malaria from being transmitted to people when mosquitoes feed on human blood.
In other words, the new mosquitoes are genetically incapable of infecting humans with malaria, which kills about 1 million people each year.
But all good things come with risks. Scientists and environmentalists fear that releasing GM mosquitoes into the population could “amplify the frequency of synthetic genes within a natural population of breeding insects poses the risks of ‘unintended consequences’ if safety concerns are not addressed,” writes the Independent.
Scientists released GM mosquitoes in Florida several years ago that were “designed” to eradicate dengue fever, but they were shown to be fairly ineffective and experts warn there was a chance the Franken-skeeters could spread the disease even further by reducing immunity to the more serious form of dengue – which is exactly what happened in Brazil.
Panamanian researchers also warned that the Asian tiger mosquito, which also transmits dengue and chikungunya, could move in and be harder to destroy. 
“[Gene editing] is a little bit like geoengineering,” MIT researcher Feng Zhang told the New Yorker earlier this month of the new malaria-blocking mosquitoes. “Once you go down that path, it may not be so reversible.”
For now, the GM mosquitoes are hidden away in a highly secure lab behind multiple locked doors as both science and society tries to figure out when and how the insects should be released, and what will happen when they are.