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IT is the curse of lush, warm places. Wherever there is greenery, blooming plants and bulbs and leaf-laden branches, we can find the mosquito. Wherever there is standing water — from fetid pools of slime to ornamental ponds and even swimming pools — so too, there is the mosquito.
In the best-case scenario, mosquitoes will stick their proboscis into unassuming human flesh and take vast sips of healthy blood. In the worst-case scenarios, mosquitoes will not only suck blood but also leave something behind to endanger human life. Some of the world’s worst illnesses are transmitted by disease-carrying mosquitoes — malaria, dengue, yellow fever and the Zika virus infection all rely on small parasites to spread diseases everywhere — from the slums of Mumbai to the Florida Keys, the southernmost outpost of southern United States.
The Florida Keys is where the story of a new kind of mosquito begins. Back in 2009 and 2010, the group of islands, known for its tropical and lush environs, experienced an outbreak of dengue. The Florida Keys Mosquito Control District and similar bodies felt that their tools against the sort of mosquitoes spreading it were diminishing. Heavy use of insecticides to control the mosquito population only meant that many mosquitoes were becoming resistant to insect-killing substances. The large-scale use of toxic insecticides was also quite problematic because of the harmful impact on the surroundings as they poisoned plant and other life forms. The price for not coming up with an effective remedy was that the number of mosquito-borne illnesses started increasing every year.
An answer was then found by the biotechnology firm Oxitech, which noted that disease outbreak occurred when there was an increase in the Aedes Aegypti mosquito population. It was recognised that altering this particular type of mosquito, which is responsible for dengue from Brazil to the Cayman Islands, to many other parts of the world, including South Asia, would lead to a decrease in the number of vector-borne illnesses. Oxitech, which is based in the UK, altered the Aegis Aegypti genome and came up with a new type of mosquito. The idea was that this genetically engineered male mosquito would mate with the female Aegis Aegypti, which is responsible for the spread of the diseases mentioned, but only male offspring, which would not bite, would be produced. And so a decrease in the total number of mosquitoes would be witnessed.
The sort of solution that a biotech firm sought to decrease the mosquito population, and thus limit disease, is an eye-opener.
The company had to fight an uphill battle to actually release their genetically altered mosquitoes into the population. Finally, in May of last year, the company was able to get permission to carry out the trial of their mosquitoes in the Florida Keys. Even the release required care and planning. The company prepared three boxes of male mosquito eggs and set them up in three different locations in the Florida Keys. The boxes released thousands of engineered mosquitoes to mingle with the wild mosquito population and mate with female mosquitoes. It was believed that the population of female mosquitoes would thus be curtailed by the modified gene, and the non-biting male offspring would pass on the gene to the next generation.
This sort of solution is likely to become ever more common as rising temperatures, climate change and other natural forces cause an increase in pandemics and parasite-borne diseases the world over. Already, the capacity of local governments to counter the spread of dengue and malaria and all other mosquito-borne diseases has been severely reduced as resources have gone into fighting Covid-19. This leaves those who live in damp and musty areas, often with standing pools of water inside and outside their homes, particularly vulnerable to vector-borne diseases.
Altering the genetic composition of mosquitoes may seem like too much human meddling in the ways of nature, but then altering any disease, even with the use of vaccines or medicine, is to intervene in ‘natural’ processes. If humankind is to continue to exist, it must use the intellectual capital available to it to fight diseases that cause so much human suffering.
This summer, Oxitech released the results of its mosquito experiment. The genetically engineered male mosquitoes successfully mated with wild female Aedes Aegypti mosquitoes. The progeny had a gene that could not produce female mosquitoes. At this point in the life cycle, it appeared that the number of Aedes Aegypti had been reduced in places where the experiment was carried out. However, while the plan had predicted that male mosquitoes with the modified gene would continue to exist, further investigation is needed as after a few generations of mosquitoes, all traces of the engineered gene vanished. Had the vile mosquito figured out a way to root out the lethal gene from its population so that it could continue to propagate as before?
So far it seems that the experiment has been a limited success. For a few generations, the number of Aedes Aegypti were reduced; but more work has to be done to outwit the species in the long run. After all, just as humans want to evade disease and survive, so too do mosquitoes. It appears that no wild female mosquito apparently wanted to mate with male mosquitoes that would transmit the gene to their male offspring.
Nature is cruel and harsh and geared towards survival alone. Mosquitoes try and humans try and even viruses try to live on and continue into future generations. The ravages caused by the Covid-19 pandemic these past years have expedited efforts to find new cures and preventive strategies. Just as in the case of the mosquito trials, the coming years will witness determined efforts to counter creatures that pose a threat to human health and life. The world is finally ready to take them on.
The writer is an attorney teaching constitutional law and political philosophy.
Published in Dawn, April 27th, 2022
