Posted on June 1, 2016 at 5:48 PM
by Craig Klugman, Ph.D.
One of the first news articles I ever wrote in journalism was as an intern at Stanford Magazine. This piece was on research into a human vaccine that would do nothing for us, but would kill any mosquito who happened to bite an inoculated person. The researcher’s ethical question at the time was whether anyone would consent to getting a vaccine that does nothing for her or his personal health.
Twenty-five years later, and this month Smithsonian Magazine published an article on CRISPR-9 gene-editing techniques that will allow for the eradication of mosquitoes. A group of scientists introduced a mutation into female mosquitoes that caused infertility—the mutation spread to 75 percent of that specific mosquito specie’s population. This possibility raises the question of whether such a mutation should be released that has as its goal, the elimination of an entire species.
The same question has been raised by the WHO which is debating whether the remaining samples of the smallpox virus should be destroyed. The only two sources (that we know of) are at the CDC in Atlanta and the State Research Center of Virology and Biotechnology in Russia. For many years, the argument in favor of keeping it around was in case we needed to create a vaccine. But such vaccines can now be made without the virus. One fear is that if someone got a hold of the remaining stock, that a bio-terrorism weapon could be created. The other fear is whether humans should deliberately eradicate any species.
In the 1950s we began a program to eradicate the screwworm (a bane to ranchers) by sterilizing the males of the species using radiation, a process that has taken decades and has not quite led to the extinction of the species.
However, humans may now be responsible for what is quickly becoming the sixth mass extinction of species in Earth’s history. About 20,000 species are facing extinction, a level that is 1,000 times greater than the natural rate of loss. Humans are blamed for this higher rate of potential extinction because of our responsibility in climate and habitat change. The risk is that 30% of all existing species (14,000 to 35,000) may be extinct in the next few hundred years.
Would anyone miss mosquitoes? They carry diseases such as malaria, yellow fever, and zika. They also pollinate plants and serve as food for fish and birds. They are an especially abundant food source in the Artic for birds. Given the large biomass of insects in the world overall, scientists believe that other creatures would fill the hole in the food chain.
In the Smithsonian article Hank Greely says that we should consider whether we want to deliberately eliminate a species, warning against the slippery slope of wanting to kill off other species as well. What he doesn’t mention is that many good intentioned programs to eliminate pests often have unintended consequences. For example, consider the class case study of Australia where Europeans introduced new species to control pestilent ones. The consequence was an ecological disaster with foreign species outcompeting native ones, which led to the introduction of new species to deal with those, and so on.
In the case of smallpox, keeping the remaining stocks seems nostalgic. Our reluctance to kill the virus seem focused on two issues: (1) avoiding the responsibility and guilt for deliberately erasing a species from the planet and (2) concerns that perhaps specimens have made their way into terrorist hands and could be unleashed on an immunity-naïve population. The mosquito question has similar concerns with the difference that smallpox is confined to being a human infection and mosquitoes serve other purposes in the ecosystem. The loss of smallpox, which has been out of the natural environment for decades, is mostly symbolic. The loss of mosquitoes would leave a hole in the ecosystem, one that other species would quickly fill.
Ironically, we anguish over deliberately causing the extinction of these 2 pestilent species, but we take little action to change our behaviors and practices that are leading to one of the greatest mass extinctions the planet has even known.