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About this Article
Written by: Christopher Romero
Written on: April 4th, 2003
Tags: biomedical engineering, health & medicine
Thumbnail by: Illumin
About the Author
In the spring of 2003, Christopher was an engineering student at the University of Southern California.
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Volume V Issue III > A Genetic Solution to Malaria: More Harm Than Good?
Malaria continues to plague peoples worldwide, transmitted by a viral parasite carried by mosquitoes. Vaccines and pesticides have combated the disease in the past, but the disease adapts and becomes resistant to drugs, and pesticides such as DDT hurt the environment while killing mosquitoes. Geneticists have developed a new solution to this age-old quandary-a genetic alteration of the mosquito's physiology that keeps it from transmitting the disease and passes this characteristic to its offspring. However, overwhelming ethical questions in testing and implementing this innovation deserve careful consideration by society.

Introduction

Illumin
Figure 1: Parasite-carrying mosquitoes are the cause behind millions of deaths a year.
Every year, up to 2 million people are killed by malaria worldwide. Typically transmitted by parasite-carrying mosquitoes in underdeveloped countries where sanitation is poor and preventative strategies are failing, malaria, which was once "eliminated or largely controlled for 90 percent of the world's population, now threatens more than 40 percent" of all humans [1].

Ineffectiveness of Drugs, Vaccines, and Pesticides

So, what has been done to harness this powerful epidemic? Anti-malarial drugs, vaccines and pesticides have been developed, but both the host (i.e. the mosquito) and the protozoan parasite, one of four disease-causing species of the viral genus Plasmodium, have grown resistant to these technologies, demonstrating why malaria is one of the most dangerous diseases.
One pesticide, known as DDT, was very effective in eliminating mosquito populations; however, its natural degradation is very slow and its toxicity to all organisms is high. DDT accumulates in biosystems, increasing in concentration through the food chain and cumulating into a fatally toxic dosage, as evidenced by diminished bald eagle populations of North America. Furthermore, many species of mosquitoes have become resistant to this insecticide. Due to this, the World Health Organization (WHO) no longer uses DDT, and no other environmentally safe pesticide has been discovered.
After "research to create a [permanent] vaccine for malaria failed in the 1980s," very few methods of controlling malaria remained. Without any effective pesticide to limit large mosquito populations, geneticists suggested an alternative strategy. Believing that the resistance of Plasmodium to anti-malarial drugs would ultimately hinder vaccine research, geneticists such as UC Irvine's Anthony James turned their focus to the possibility of genetically altering mosquitoes, thereby making them incapable of transmitting the disease.

Genetically-Altered Mosquitoes

While the technology to effectively activate and inactivate specific genes is very complex and currently being refined, the concept of this strategy is simple. Say, for example, geneticists did build such a mosquito and released it into an environment affected by malaria. If the genetically altered mosquito were to mate with wild-type mosquitoes (i.e. mosquitoes that have not been genetically mutated) and successfully pass on its genes to its progeny, then, theoretically, nearly the entire population would eventually be incapable of transmitting malaria. The benefits of such a technology would be enormous: millions of lives would be saved, and governments need only purchase a handful of mosquitoes rather than meet the high cost of anti-malarial drugs or negotiate compulsory licenses (i.e. contracts allowing poorer nations to generically manufacture drugs). The greatest long-term benefit, of course, would be the eventual containment and possible elimination of malaria'a goal the WHO deemed impossible in 1969 [1].