What if there was a way to modify the mosquitos to resist the disease, rather than killing their wild populations? That’s the new approach being undertaken by scientists at John Hopkins University to combat the deadliest mosquito-borne threat of all: malaria.
How can genetic engineering fight diseases that are transmitted by mosquitos? Science can use it to alter our genes, so we’re resistant, or we can change the genes in mosquitos to make it impossible for them to infect us with these diseases.
Mosquitos transmit diseases that are responsible for the deaths of more than half a million people around the world each year. These small, fragile creatures carry and infect humans with, diseases such as malaria, yellow and dengue fevers, and Zika virus. Genetic engineering in humans is in its infancy, but science has been working to genetically modify mosquitos for years – in the hope to decrease the deaths caused by these mosquito-borne diseases.
Reducing the mosquito population
To date, the primary approach has been to use genetic engineering to sterilize mosquitos. A company in England called Oxitec has engineered Aedes aegypti mosquitos carrying the Zika virus to carry a lethal gene. It kills the offspring they have, preventing further mating with wild females. The objective is to reduce mosquito populations to control the disease.
But, what if there was a way to modify the mosquitos to resist the disease, rather than killing their wild populations? That’s the new approach being undertaken by scientists at John Hopkins University to combat the deadliest mosquito-borne threat of all: malaria.
These scientists are using a gene-editing technique called CRISPR/Cas9 to remove the FREP1 gene from Anopheles gambiae mosquitos. Editing out this one gene has been shown to make these mosquitos less susceptible to the parasite responsible for malaria in humans.
Several proteins contribute to helping the Plasmodium parasite make its way to the mosquito’s salivary gland. The mosquito then transmits this parasite to humans when it bites us. When the CRISPR editing process is used to delete the FREP1 gene, it interferes with the parasite’s ability to use mosquitos as a vector.
If it successfully prevents the transmission of malaria, it would prove to be a major advance in fighting a disease that infects hundreds of millions of people, killing hundreds of thousands of us yearly.
Not ready for prime time
There are a few obstacles to overcome first. These genetically modified mosquitos are identical to those in the wild except for one small thing. They glow because of a green fluorescent protein that’s introduced to track modifications. Their non-modified friends don’t seem to notice or care – and it’s not what’s really causing the problem.
It turns out that deactivating the FREP1 gene renders these mosquitos less hardy. That would be fine if the objective were to reduce their population. But scientists want these genetically modified mosquitos to mate with wild ones to spread the malaria-resistant DNA. The concern is that these weaker genetically modified mosquitos may not be able to compete for mates successfully.
Ironically, despite how tenacious they seem when they’re bothering us, mosquitos are fragile compared to other insects. Anything that even slightly weakens them – such as the CRISPR gene modification – could make them ineffective potential mates in the wild.
Is it safe?
Even if researchers find a way to genetically modify these mosquitos, so they’re just a robust as their wild counterparts, there’s yet another obstacle. Many humans aren’t sold on the idea of messing with DNA – even if it is a mosquito’s.
Overwhelming public opinion prevented Oxitec from advancing with trials of its genetically modified mosquitos in Key West, Florida. People there voiced their concerns about unknown and unintended consequences that might change the insect’s behavior. Could it cause a catastrophic chain reaction in the ecosystem? No one has an answer to these questions.
Genetically modified mosquitos may someday help us put an end to deadly diseases like malaria. In the meantime, you can keep your home safe from mosquitos, fleas, ticks, and other nasty insects with a misting system. Discreetly placed around your yard, it will keep these biting bugs away from your property. To find out more about how this system works or to get a free onsite consultation, contact Platinum Mosquito Protection.