The world’s greatest killer is at it again. It’s relentless – spreading pain, suffering and heartache everywhere in its wake. Its bite is a mere pinprick, yet it has the potential to transmit deadly pathogens into bloodstreams within mere seconds. We’re speaking of mosquitoes, of course.
Mosquito bites result in the death of up to 1 million people worldwide each year, most of them from malaria transmitted by these pesky insects. Throughout history, mosquitoes may well have contributed to the death of almost 50% of the people who have ever lived. And it isn’t just malaria that mosquitoes spread; they are also vectors for dengue fever, yellow fever, West Nile fever, Zika and other diseases.
The viruses that cause these debilitating and often lethal diseases (which are especial risks to children, the elderly and people with compromised immune systems) are transmitted by the females of the blood-sucking insects. To make matters worse, mosquitoes often proliferate inside and near houses where stagnant water is left in accessible containers, such as in water tanks, reflecting pools and flower pots, allowing them to lay their eggs.
Even many environmentalists, who otherwise work tirelessly to save endangered species, believe that the time has come not just to “manage” situations but to do away with disease-carrying mosquitoes once and for all. That’s easier said than done, however, considering the ease with which mosquitoes can breed and proliferate, defeating almost any effort that aims to do more than merely contain them.
Yet scientists worldwide are working on solutions to eliminate Aedes aegypti mosquitoes for good. In Colombia, specialists have been trying to infect mosquitoes with Wolbachia bacteria, which block the insects’ ability to pass on diseases to their human hosts. In Mexico, scientists have been zapping male mosquitoes with radiation to make them sterile before they set the male insects loose among wild female populations in the hope that females will no longer be able to produce any offspring.
In the United Kingdom, meanwhile, geneticists at the University of Durham have been working on manipulating the genes of males so that their offspring will all be sterile. Yet other scientists, at the University of York, have in turn been investigating an insulin-binding protein found in fruit flies and other insects like mosquitoes. They are hoping to work out ways to prevent the protein from activating hormones that sustain the lifespan of mosquitoes.
In other words, it could just be a matter of time before scientists manage to come up with ways to stop mosquitoes to spreading deadly diseases. That said, some environmentalists have warned that by interfering with nature we could upset the delicate balance of certain ecosystems. By spreading diseases to a variety of animals, mosquitoes perform a useful ecological function by keeping their numbers in check.
So perhaps we should think twice before we set out to eradicate mosquitoes. Or maybe not. “Ultimately I wouldn’t be too sentimental” about killing them off, stresses Prof. Steve Lindsay, an entomologist at Britain’s University of Durham who is working on the gene manipulation of mosquitoes. “I have no problem with taking out the mosquito.”
