So… what animal is the most dangerous to humans? That is, what animal kills more humans than any other each year?
Almost for certain you have had direct contact with one, or one of their “cousins”, multiple times in your life. Think about it for a bit. As this is a gun blog, what caliber of gun do you think would be most effective in defending yourself from this beast?
If I were the betting type I would bet you chose wrong. Almost for certain this animal would sneak in past your defenses and bite you on the neck without you being able to get off a single shot in its direction. Guns are essentially worthless against it.
What is this deadly beast? Alien? Predator? An escapee from Jurassic Park?
Omar Akbari, a molecular biologist and assistant professor of entomology at the University of California, Riverside says:
Aedes aegypti is literally probably the most dangerous animal in the world.
And from the same article:
The same type of mosquito caused dengue to proliferate from Southeast Asia through tropical regions world-wide during the last quarter of the 20th century. The dengue virus infects an estimated 390 million people a year, killing thousands of them.
Aedes aegypti also is a carrier of chikungunya, a crippling disease that causes lasting joint pain, and yellow fever. In southern Africa, officials are struggling to contain a large outbreak of yellow fever, which can lead to fatal liver disease.
And another type of mosquito transmits malaria which kills nearly a half million people each year.
But scientist are working on genetic tools that could possibly direct selected species to extinction:
Imperial College London researchers are refining a system under development for the past several years to drive a self-destructive genetic trait into the Anopheles gambiae mosquito, the major carrier of malaria in sub-Saharan Africa. The trait could eventually shrink the malaria carrier’s population. Malaria kills an estimated 438,000 people a year.
With Crispr/Cas9, scientists can use an enzyme to snip DNA and insert changes, then build something called a “gene drive” that makes those changes more likely to be inherited by future generations, altering them. Normally, genes have only a 50% chance of being inherited.
Prof. Adelman and Virginia Tech biochemistry professor Zhijian Tu see a way to do this with genes involved in mosquito reproduction. In a paper published in Science last year, the researchers identified a gene that makes Aedes aegypti mosquitoes male.
“This was the master switch that controls sex,” says Prof. Tu. He and Prof. Adelman were co-authors of the research.
The researchers now are working on a system to program mosquitoes to develop as males. Since only females bite, that change could reduce the ability to spread viruses. The researchers aim to then use Crispr/Cas9 to build a gene drive that would spread the change through successive generations.
“If you’re successful, then you end up with all males, and the local population crashes,” says Prof. Tu. Prof. Adelman cautions that a system to target Aedes aegypti would have to be designed to leave the African forest-dwelling mosquito Aedes aegypti formosus intact. That type of mosquito doesn’t threaten human, he says.
Prof. Akbari at UC Riverside is using Crispr/Cas9 to design a gene-drive system that would inactivate a fertility gene in female Aedes aegypti mosquitoes and then pass on the inactivated gene. That would sterilize future generations of females.
The tradeoff is millions of human lives saved versus the preservation of the most deadly animals on the planet. Which will we chose?