Follow Africa and latest USA research: Eradicate dengue, zika and chikungunya

By Dyan Seneviratne

And so the terrifying ‘Dengue Season’, of Sri Lanka, not mentioning the onset of the paralysing chikungunya is about to hit us from India – maiming thousands; of course dengue even kills at times. Whilst numerous steps have been taken to minimise these deadly mosquito attacks, it still appears to be a losing battle. More and more of our citizens are bound to suffer immeasurably and even end up having a tryst with their Maker – already the official ‘Dengue death toll’ in Sri Lanka for 2016 is nudging 50! And counting, sadly!

Should this situation prevail? During the 50s and early 60s, dengue was unheard of and even malaria was under control due to DDT spraying. Fogging is the new mode against mosquitoes, but is it effective and does it kill? Not really! We need to attack the source in more ways than one. So please read on…..

Okay, health authorities have proudly proclaimed that SL is free of malaria; but what about dengue? Why have we not taken proactive measures to combat dengue and indeed eradiate it with the help of earlier measures that were successful and indeed embrace biological and even mosquito DNA altering methodologies? 

In this context, for the benefit of readers, let me turn the spotlight to Africa and quote extracts from a back-issue of ‘Newsweek’ – 24 September 2007, captioned:  ‘To fight Malaria, African nations are turning to DDT’ – By Scot Johnson.

“Fifty years ago Africa had a coherent strategy to fight malaria. It involved spraying large amounts of the pesticide dichlorodiphenyltrichloroethane, or DDT, to curb the mosquito that carries malaria. This campaign was hugely successful, but it came to a halt shortly after the 1962 publication of Rachel Carson’s ‘Silent Spring’, which described the environmental consequences of DDT running off into lakes and rivers. Then malaria cases soared (once again) in the African Continent, except in South Africa, which continued to spray DDT. Finally, in 1996 pressured by environmental groups, South Africa dropped DDT for a less toxic alternative (like in Sri Lanka – stopping DDT and spraying some other chemical which has proved to be less potent – in fact, useless!) Four years later South Africa was facing its first malaria epidemic in half a century.”

“Now the story has turned back again. South Africa resumed spraying in 2000, and malaria outbreaks declined. Health officials from South Africa and the United States helped persuade the World Health Organization (WHO) to approve DDT for malaria control, saying the benefits were worth the risks.” 

“Today South Africa stands virtually alone on the continent, having gotten malaria under control again. (Zambia followed its lead, with similar results.) Now the rest of the continent is coming along as well. Last year Mozambique embarked on a limited spraying campaign; health officials say they see signs of improvement. In November, Uganda will roll out a large-scale DDT regime, backed by its President, Yoweri Museveni. Tanzania and Kenya are both considering starting DDT-spraying campaigns.”

“The return of DDT is part of a broader recognition that controlling malaria is a high priority for Africa – and that fighting it will require all the tools health officials can muster.” 

“US First (former) Lady Laura Bush recently visited Mozambique on behalf of the $ 1.2 billion President’s Malaria Initiative to promote, along other measures, the use of DDT in 15 African countries. DDT will be an important tool to help further reduce the annual malaria death toll in Africa, which is now 1 million, most of them children.”

“Rachel Carson’s claims about DDT may have been exaggerated, but scientists have changed their assessment of the risks in recent years. Whereas large-scale, indiscriminate spraying is harmful, targeted spraying in small amounts can deter mosquitoes with little effect on humans.”

“DDT’s main virtues are that it’s cheap – six times cheaper than alternative pesticides – and long-lasting. One dosage can work for nine months, long enough to span peak malarial seasons in most places. “I’m thrilled about it,” says Maureen Coetzee, chief of vector-control research at South Africa’s National Institute for Communicable Diseases. “It’s long over-due.” The Gates Foundation is pouring nearly $ 5 million into Africa to make sure DDT and other insecticides are used properly.”

“The Environmental Defence Fund, which once promoted: ‘Silent Spring’ and helped champion the movement to ban DDT, has endorsed its limited use for malaria control. While North America and Europe were fighting malaria in recent decades, it seemed that health experts had written off Africa as too difficult. They’ve changed their minds on that, too.” [Source: Newsweek Sept. 24 2007]

Reading aforementioned authoritative study courtesy Newsweek of 24 September 2007 (and not some moth-eaten, ancient parchment!) it is evident that banning DDT in the early 1960s appears to be based on some exaggerated claim against DDT. 

So if we realistically wish to eradicate life-threatening dengue, crippling chikungunya, disfiguring filaria, the zika threat etc the authorities in Sri Lanka should take cue from African nations and resume spraying of DDT, albeit on a limited, regulated scale and STOP this raging dengue epidemic and prevent another future outbreak – PLEASE!

Introduce mosquito larva gobbling fish species in waterways, streams 

Also pour waste oil in unused gem-pits, wells, gutters etc.

Apart from awareness campaigns re mosquito breeding/prevention and spraying of DDT, may I also suggest that introduction of specific fish species that would make the mosquito larvae their meal! 

I remember as kids the numerous water-ways and streams that abounded in Nugegoda had plenty of ‘Gappies’, Maguras and Kaaviayas – mosquito larvae then was unheard of. So please create the conditions for these life-saving fish back to all our little water-ways, pronto!

Further ‘Waste Oil’ should be poured into pits such as Gem-Pits and such appropriate pits/unused well etc. The thick film of oil would effectively prevent the larvae from breathing – killing it! The writer has personally done so, successfully, during his days managing large tea/rubber plantations.

Another common ‘mosquito breeding ground’, often overlooked are roof gutters; invariably clogged with leaf litter if your house has trees growing nearby. Do make it a point to clean up your ‘roof gutters’ at least weekly; if the water in gutters do not move to the ‘down pipes’ then increase the gradient and/or bore holes every 10 inches or so; if your ‘Handy-Man’ who would do the boring is no longer around as he has morphed into a ‘Trishaw Driver’, then you need to pour some ‘engine oil’ left over from your last car/motor bike service vide above paragraph re the efficacy of waste oil film that suffocates the pesky larvae! Also do check water storing tanks; are they sealed or at least covered enough to prevent mosquitoes from entry; if not here’s another ticking ‘Dengue bomb’!

USA’s on-going research on mosquito war

Even at time of writing Global Research Institutes, notably in USA are in process of making available some wonderfully innovative methods of countering the deadly mosquito. For example scientists at Columbia University are trying to block a mosquito’s sense of smell so it can’t find humans to bite! Others at Virginia Polytechnic Institute are developing pesticides that activate only inside a mosquito, thus posing no danger to humans or other animals – ‘zero mammalian toxicity’, as a scientist would say – wow! That’ll be the day! 

There are 3,500 species of mosquito, but only a few species and only females that ‘attack’, or bite, kill and maim humans; the mosquito that carries dengue fever infects as many as 400 million people a year, as well as such increasingly threatening pathogens such as Chikungunya, West Nile virus and Zika. 

In an ever widening outbreak that began last year in Brazil, Zika has ‘spread its evil wings’ to SE Asia, notably Singapore, Malaysia, Thailand etc. Zika appears to cause a variety of neurological disorders, including a rare defect called ‘Microcephaly’ where babies are born with abnormally small heads and under-developed brains – an absolute tragedy to those affected directly and indirectly. 

New crusade against mosquitoes by USA’s molecular geneticist, James

Let’s turn our attention [vide National Geographic magazine Aug 2016] to a new messiah who is carrying on a crusade against the killer mosquito globally: “I have been obsessed with mosquitoes for 30 years,” says James, a molecular geneticist at the University of California, Irvine, USA. 

The goal of James’ lab, and of his career, has been to find a way to manipulate mosquito genes so that the insect can no longer spread such diseases. Until recently, it has been a long, lonely, and largely theoretical road. But by combining a revolutionary new technology called CRISPR-Cas9 with a natural system known as gene drive, theory is rapidly becoming reality. [Ref: N. Geo Aug 2016]

Is CRISPR-Cas9 gene-altering of mosquitoes way to go in future? 

CRISPR-CAS9 has two components. The first is an enzyme – Cas9 – that functions as a cellular scalpel to cut DNA. [In nature, bacteria use it to sever and disarm the genetic code of invading viruses.] The other consists of an RNA guide that leads the scalpel to the precise nucleotides – the chemical letters of DNA – it has been to cut. [By the way CRISPR stands for: clustered regularly interspaced short palindromic repeats.”]

The guide’s accuracy is uncanny; scientists can dispatch a synthetic replacement part to any location in a genome made of billions of nucleotides. When it reaches its destination, the Cas9 enzyme snips out the unwanted DNA sequence; to patch the break, the cell inserts the chain of nucleotides that has been delivered in the CRISPR package.

Reverting to Zika, by the time the outbreak in Puerto Rico comes to an end, an estimated 3.5 million people in Puerto Rico may contact Zika and that means thousands of pregnant women are likely to become infected. Here James and others say that editing mosquitoes with CRISPR – and using a gene drive to make those changes permanent – offers a far better approach. 

Last year, in 2015, a study published in the Proceedings of the National Academy of Sciences, James used CRISPR to engineer a version of Anopheles mosquito that makes them incapable of spreading the malaria parasite. “We added a small package of genes that allows the mosquito to function as they always have,” he explained. “Except for one slight change”: That change prevents the deadly parasite from being transmitted by the mosquitoes. 

CRISPR places an entirely new kind of power into human hands. For the first time, scientists can quickly and precisely alter, delete and re-arrange the DNA of nearly any living organism, including the deadly mosquito.  

To fight off dengue, James and his colleagues have designed CRISPR packages that could simply delete a natural gene from the wild parent and replace it with a version that would confer sterility in the offspring. If enough of those mosquitoes were released to mate, in a few generations [which typically last just two or three weeks each] entire species would carry the engineered version. James says, “There are certainly risks associated with releasing insects that you have edited in lab, but I believe the dangers of not doing it are far greater.” Way to go!

Whilst the future appears heartening, at least where research is heading, one should be realistic in this part of the world. For the present – get back to the past! DDT appears to be the way forward, like at Africa. Let us then go for DDT!  So to recap: Re-introduce DDT [Follow African countries who are doing so NOW], introduce FISH in waterways in slow-moving rivers that harbour mosquito larvae; pour Waste Oil into gem-pits/unused wells etc – another effective method of killing the mosquito larvae. Take an open and proactive stance re DNA altering of mosquitoes. Of course prevent mosquito breeding in the first place, following the oft repeated, cliché-tic adage: Prevention is Better than Cure!

Let us ‘all’ aim to eradicate dengue, chikungunya, filaria and prevent zika from ever becoming a scourge like dengue. We can collectively! 

After all, the mosquito still is to this day just an insect smaller than a child’s thumbnail, yet it remains the most dangerous nonhuman animal on the planet! 

Our people deserve better than to suffer excruciating pain and even to die – preventable deaths! So Sri Lankan health authorities and the general public – with October 2016 declared ‘Dengue Prevention Month’ it’s opportune that you wake up from your slumber now! Tomorrow may be too late!