Malaria has been described as “the perennial scourge of mankind,” with over 200 million cases reported annually resulting in up to 750,000 deaths and incalculable misery. The disease is most common in the tropical and subtropical regions that surround the equator, including Sub-Saharan Africa, Latin America, and Asia, but it may be found in any region where climatic conditions favor the growth and spread of the mosquito-borne parasite.
On-going global eradication efforts employing pesticides have been successful in southern Europe and the southern United States, but less so elsewhere. In recent years genomics has taken center stage in malaria research with the sequencing of both the malarial parasite and the human genome. One experimental application of this research is the production of genetically-modified mosquitoes that do not transmit malaria. Another new and promising technique is the gene drive, which combats malaria by introducing disruptive genes into wild populations of mosquitoes that interfere with the development of females.
The use of such radical measures unavoidably prompts serious bioethical concerns, including the possibilities of unforeseen mutations and broader ecological impacts. Ethicists also question whether we have the right to potentially eliminate a species. In her self-described role as a “moral philosopher” Laurie Zoloth (University of Chicago) has written and lectured extensively about these issues, arguing that:
In the 1960s, the world agreed that smallpox was a species worth eliminating. We should feel the same way about A. gambiae. And isn’t deploying a gene drive that specifically targets the mosquito species that carries malaria far better than using chemical sprays, such as pyrethroids, organochlorines and DDT (still used in some countries) that indiscriminately target any insect?
Though malaria and other insect-borne diseases have historically been associated with Third World poverty, Zoloth notes these maladies are no longer the exclusive province of underdeveloped tropical countries. As climate change results in greater and more widespread extremes of temperature, rainfall, and humidity, the range of mosquitoes is likely to increase, and with them the diseases they transmit including malaria, dengue, yellow fever, and Zika. While acknowledging the dangers of meddling with the genetic status quo, Zoloth maintains that preoccupation with those risks is a luxury afforded only to those who are not at risk of losing a loved one to wrenching fevers and severe dehydration.
Zoloth concludes that in that light, gene drives and other genomic-based eradication methods represent the most moral and ethical choice available to scientists.