1/05/2020

MALARIA RESEARCH : NAZI BUG KILLER


A DDT-like compound developed in World War II could help combat malaria.

What if, after the Allies won World War II, world health officials had employed a Nazi version of DDT against mosquitoes that transmit malaria? Could that persistent disease, which still infects more than 200 million people a year and kills 400,000 of them, have been wiped off from the planet.

That is one of the musings of the chemists at New York University who came across an insecticide developed by a German scientists during World War II, in the course of conducting abstract research on another topic.

In postwar Allied intelligence reports examined by Michael D. Ward, a chemistry professor at New York University and his colleagues, German scientists claimed their insecticide, now called DFDT, was more effective than DDT.

Allied officlals dismissed those assertions as fanciful, and the insecticide was forgotten for decades.

Now, work by Dr. Ward and his colleagues, reported this month in the Journal of American Chemical Society, appears to corroborate the German claims. The forgotten compound killed mosquitoes in as little as one-fourth as much time as DDT.

DDT, initially regarded as a miracle chemical , was sprayed profusely after World War II until environmental concerns arose in the 1960s. Although many nations banned it in the 1970s, some use continues.

In 2006, the World Health Organization endorsed the use of DDT as part of efforts to control malaria, primarily for the spraying of indoor walls. That involves much smaller amounts than were used by farmers in the past.

Conceivably, the more lethal DFDT could be used in even smaller, possibly safer, doses.

The effectiveness of DDT [ an abbreviation for Dichloro-diphenyl-trichloroethan] as an insecticide was first discovered in 1939 by Paul Hermann Miller , a Swiss chemist. His company J.R.Geigy, is Basel, patented the compound.

The United States and other Allies licensed DDTY from Geigy and manufactured as much as they could to control malaria and typhus during World War II. After the war, DDT was widely used by farmers.

An aggressive effort by the World Health Organization to eradicate Malaria in 1955 succeeded in some parts of the world, but many mosquitoes subsequently developed resistance - the survivors were more likely to possess a genetic trait that protected them from the poison., and they passed this to their off-spring. The disease roared back.

A turning point leading to the decline of DDT was the publication in 1962 of ''Silent Spring'' by Rachel Carson, which documented the ecological devastation caused by the indiscriminate use of insecticides.

DDT molecules endure for decades and accumulate in animals higher up the food chain.

The United States banned DDT in 1972, and many other nations followed.

Dr. Ward and his colleague Bart Kahr, also an author of the paper. think the outcome might have been different if the substance developed by the Nazi-era scientists had been used instead.

The New York University chemists started the research with no interest in insecticides, whatsoever. They were studying materials that crystalize in twisted helical pattern. DDT, they found exhibited the characteristic pinwheel gradients of a helical crystal when illuminated with a polarized light.

Jingxiang Yang a postdoctoral researcher at New York University, started growing DDT crystals and found not only the expected crystals but also more jumbled chaotic patterns.

This led to the next set of experiments. ''Since we have two forms,'' Dr. Kahr said, ''it was natural to ask, which of these forms was the historical killer of insects?''

It turned out that the chaotic form of DDT is deadlier.

As they were going through early scientific data on DDT, the New York University chemists found mentions of DFDT. The compound, difluorodiphenyl-trichloro-ethane, is the same molecule as DDT, except with flourine atoms replacing two of the chlorines

In the New York University experiments, DFDT killed off half of the mosquitoes subjected to it in about half an hour, compared to a couple of hours of DDT.

The honor and serving  of   the latest breakthroughs in research on Malaria, continues. The World Students Society thanks author Kenneth Chang. .

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