A genetically modified mosquito could eradicate malaria, a recent study has revealed on Monday, November 23.
The promising findings were published in the online edition of the Proceedings of the National Academy of Sciences. They suggest that by adopting this new solution, in conjunction with other strategies, the deadly mosquito-borne infectious disease could finally be vanquished.
According to estimations released by the World Health Organization, malaria will sicken around 214 million people across the world this year, causing the death of 438,000, especially in Sub-Saharan Africa, where 91% of the fatalities are predicted to occur.
The initial symptoms of this illness transmitted mostly by female mosquitoes normally appear in 10 to 15 days, and consist in vomiting, fever, fatigue, chills and headaches. Left untreated within the first 24 hours, malaria impedes vital organs from receiving adequate blood supply, and this can be fatal in many cases.
Experts at the University of California achieved ground-breaking progress in combating this life-threatening disease, by employing genome editing, a powerful genetic engineering procedure which allows DNA to be inserted, trimmed or substituted thanks to “molecular scissors”.
The CRISPR-Cas9 gene-altering technique was used on a mosquito species known as Anopheles stephensi Liston 1901, which is considered to be the primary source of infestation with malaria across urban India.
This species is actually part of the same subgenus as Anopheles gambiae, which is responsible for transmitting malaria throughout Africa.
By incorporating malaria-blocking antibodies through gene modification, they created hybrid mosquitoes which are resistant to the single-celled Plasmodium falciparum parasite responsible for malaria.
Also, thanks to a tool known as “gene drive”, mutant DNA can reach both of the chromosomes pertaining to the offspring. This way, immunity to the malaria parasite is obtained by 99.5% of the descendants, thus diminishing the risk of contamination even further.
Efficiency is boosted as these genes are propagated between successive descendants, according to Valentin Gantz, biologist at the University of California-San Diego.
While initially infection rates are reduced just by 1%, across 10 generations the protective effect of these DNA mutations soars to 99%, and this can all be achieved during just one summer.
Therefore, if these genetically engineered mosquitoes were released in the wild in order to reproduce with ordinary mosquitoes, gradually the antibodies would become part of the species’ genetic makeup.
As a result, the insects would no longer be primary vectors of malaria, and people would be protected from this disease in the future.
Other scientists had tried to genetically alter mosquitoes so as to reduce the prevalence of malaria. One such team had focused on producing DNA modifications which caused just male offspring to appear as the insects mated, thus making overall populations decline steeply.
In contrast, this newly devised strategy appears to be more humane and less damaging to the ecosystem, because it would allow mosquito populations to remain steady, but it would stop them from transmitting the Plasmodium parasite.
According to Anthony James, Distinguished professor of molecular biology & biochemistry at University of California-Irvine, the effects of this procedure would be heightened alongside other measures of malaria containment.
These could include the immunization of individuals who face a heightened risk of infection, the reduction of mosquito breeding habitats, and the extensive use of insecticide-treated bed nets which repel and kill mosquitoes.
While further research must be conducted in order to prove the effectiveness of this procedure beyond the shadow of a doubt, researcher agree that significant progress appears to have been made, although it will still take time before such techniques are embraced by governments and communities likewise.
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