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It is at this time of year, when the heat and the black rains become dehydrated and soak in our turn, that my thoughts inevitably turn to the deadliest of the world – the mosquito.
How they make havoc with our summer beach or barbecue parties, or sunset rooftop drinks. Is not it remarkable that such a treacherous little terrorist can inflict so much harm around the world?
In many ways, it's rude to complain. In the 1970s, before leaving the Financial Times Foreign Office on news missions in the "exotic" corners of Asia, I was filled with quinine pills, loaded with a lot of gin and tonic, and always checked if my hotel had mosquito nets.
Today, those of us who live in Hong Kong can, most of the time, consider mosquitoes as a social irritant rather than a life – threatening challenge. Note that in Hong Kong, last year, 102 cases of dengue (our normal challenge) were reported – 101 of them "imported" after the return of vacationers from Thailand, the Philippines from Sri Lanka or Vietnam. None of the cases was fatal.
Carefully cared for, are we able to forget how many mosquitoes die in the world – on average, they infect more than 200 million people a year with diseases ranging from malaria and dengue to Zika, West Nile, yellow fever , elephantiasis and chikungunya sounding. They kill at least 725,000 a year, according to Bill Gates and his Gates Foundation. We, humans – the world's second deadliest killer – are accused of an average annual toll of 475,000 deaths.
My impression is that mosquitoes have had a very, very long time to perfect their deadly skills – much longer than us humans. A piece of amber found in Canada has trapped a mosquito aged 74 million years.
And they have the law of big numbers on their side. An ambitious entomologist was recently challenged on Reddit to estimate the world's mosquito population, and came to the conclusion that there were about 10 million mosquitoes worldwide for every human being. They were apparently outnumbered only by ants and termites.
Due to the magnitude of the harm and irritation caused by mosquitoes (which is an innocent Spanish word meaning "little fly"), they have inevitably been targets of extermination as long as humans have the scientific and chemical resources to target them.
When Paul Hermann Muller invented, in 1939, dichloro-diphenyl-trichloroethane – better known as DDT – many thought that we finally had the upper hand over the world's bad insects, mosquitoes in the lead. His new miraculous pesticide has carved much of the world's mosquito population. He won a Nobel Prize for his brilliant invention in 1948.
The only problem was that DDT also wreaked havoc along our food chains. It was quickly banned and mosquitoes jumped back: there are good reasons why they have survived as adequately – like cockroaches – for millions of years.
Over the last 80 years, vast resources have been put into strategies to exterminate mosquitoes, or at least to erase their lethal power. Progress has been incredibly slow, but progress has been made. Organizations like the WHO, the Bill & Melinda Gates Foundation, a multitude of academic institutions and even the International Atomic Energy Agency have worked in the world whole to reduce the threat to us humans. In 2016, more than $ 2.6 billion was spent on malaria research and elimination.
Some initiatives are simple and local – like "eavestroughs" placed in the space between roofs and walls of tropical houses ("eaves") that poison mosquitoes with their poisons and their insecticides. sugar bait leaves hanging on the outer walls (male mosquitoes apparently seek sugar, and only females are blood suckers).
Other initiatives are directly derived from science fiction. The Atomic Energy Agency zaps mosquitoes with radiation to sterilize them, so that females lay sterile eggs after having their trysts. Others manipulate mosquito genes so that female offspring are killed.
In China, scientists infect mosquitoes with the Wolbachia virus, which makes them immune to Zika and dengue viruses and, therefore, unable to transmit them. A plant in Guangzhou – considered the world's largest mosquito plant – cultivates and releases about 3 million Wolbachia-infected mosquitoes each week to mate with wild females that will then lay eggs. infertile eggs.
Another Chinese initiative uses the latest military radar technology that is sensitive enough to detect the wing beats of a mosquito (they apparently have a common frequency) up to one kilometer away. This work leaves me rather perplexed. Quite how useful it is to know that a mosquito is a mile away and half escapes instead. Even more troubling, one wonders what other types of movements or activities can detect sensitive radars, but do not become too paranoid.
With so much scientific brains and money spent on eliminating mosquito threats, I feel that significant progress is being made. But this raises a distinct and distinct question: would it really be good to exterminate all mosquitoes?
As you are bitten alive during a barbecue on Sunday, there could be moments of weakness when you answer a "yes" enthusiastic. But pause a moment. Remember in the 1960s, when Mao tried to exterminate all Chinese sparrows to prevent them from looting rice and other grain stocks. As the sparrows were slaughtered by the million, insects began to infest the crops with even more damaging results.
The perverse reality is that, whatever our personal opinions, there is a delicate balance. Note that there are more than 3,600 species of mosquitoes, of which only a few hundred bite or infect us. What about all these innocent bystanders? Perhaps these exasperating creatures – ants, termites and roaches too – are for our terrestrial ecosystems what krill is for the sustainability of our oceans. Hope our scientists will succeed, but not too well.
David Dodwell studies and writes about global, regional and Hong Kong challenges from Hong Kong's perspective
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