Facts of the Matter
Facts of the Matter
Mercurial malaria
Malaria is a killer, said by many to be the world's most infectious and deadly disease. There are about 3 billion to 5 billion cases each year, causing 2 million deaths. Ninety percent of these are infants in sub-Saharan Africa. About 5 percent of deaths worldwide are caused by malaria. This number is expected to double in two decades, according to the World Health Organization.
Various cures have been discovered since the 18th century, when quinine was isolated from the cinchona tree. Resistance to quinine soon developed, and the search has been on for a new treatment or a vaccine.
Fifty years ago, it seemed that insecticides such as DDT would eradicate the anopheline mosquitoes that carry and transmit the disease. Environmental effects have made DDT and other insecticides undesirable, and efforts to curb the disease are foiled by the malaria parasite developing drug immunity.
The female mosquito's egg production is triggered by a blood meal. If the blood contains the malaria parasite, the cycle starts. The plasmodium organism breeds in the mosquito's gut, producing eggs. Each egg morphs into a cyst containing hundreds of plasmodia. When the sac bursts, the offspring travel to the salivary glands, where they await injection into the next victim, who then becomes a host.
U.S. researchers announced last month that they had genetically engineered a mosquito to resist malaria and to pass on the traits to offspring, but a new breed of mosquito suitable for testing in the field won't be ready for five to 10 years. Previous attempts to engineer malaria-resistant mosquitoes have failed.
In the new technique, researchers at Case-Western Reserve University in Cleveland slipped random DNA into the viruses that attack bacteria where the plasmodium parasite develops. They isolated proteins made by the viral DNA that would prevent the parasite from being expelled by the mosquito when it bit its victim. By tracing the protein back to the DNA, they developed a synthetic gene that was turned on whenever digestion was begun in the mosquito.
This technique may not be the answer to eradicating malaria. Many researchers today think that it will demand a combination of anti-malaria drugs and mosquito repellents along with genetic modifications.
There are dangers inherent in any transgenic organisms released into the wild, and there is opposition to genetic engineering. There has also been criticism that not enough money is being spent on developing drugs and vaccines. Some critics see a capitalistic motive since malaria is primarily a disease of poor countries that cannot afford drugs developed in the United States.
The question remains, as with much scientific research, whether the potential benefits outweigh the potential side effects.
We could all be a little smarter, no? Richard Brill picks up
where your high school science teacher left off. He is a professor of science
at Honolulu Community College, where he teaches earth and physical
science and investigates life and the universe.
He can be contacted by e-mail at rickb@hcc.hawaii.edu