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Wednesday, March 07, 2007

Nobel Laureate: Paul Hermann Müller

The Nobel Prize in Physiology or Medicine 1948.

"for his discovery of the high efficiency of DDT as a contact poison against several arthropods"

Paul Hermann Müller won the Nobel Prize in 1948 for is discovery that DDT was an effective insect poison [see Monday's Molecule #16 and DDT Blocks the Voltage-Gated Sodium Channel]. Müller was looking for a contact poison that would protect plants from insects. He extended the work of others who discovered compounds that could be applied to wool to prevent them from being ruined by moths. These compounds resembled DDT but they were not as effective. Müller's approach is described in the presentation speech ...
Paul Müller went his own way and tried to find insecticides for plant protection. In so doing he arrived at the conclusion that for this purpose a contact insecticide was best suited.

Systematically he tried hundreds of synthesized organic substances on flies in a type of Peet-Grady chamber. An article by the Englishmen Chattaway and Muir, gave him the idea of testing combinations with the CCl3 groups, and this then finally led to the realization that dichloro-diphenyl-trichloro-methylmethane acted as a contact insecticide on Colorado beetles, flies and many other insect species under test. He determined its extraordinary persistence, and simultaneously developed the various methods of application such as solutions, emulsions and dusts.

In trials under natural conditions Müller was able to confirm the long persistent contact action on flies, Colorado beetles and gnats (Culex).
Subsequent work revealed that DDT was effective against a wide variety of insects and was harmless to mammals. Among the insects that were killed by DDT were lice, the carriers of thyphoid, and malaria mosquitos.

At the time, Müller was working for the J.R. Geigy Dye-Factory Co. in Basel Switzerland and he had given samples of DDT to the Swiss Army for testing. The results demonstrated that insect borne diseases could be controlled by DDT.
At that time, the Allied Armies of the West were struggling with severe medical problems. A series of diseases transmittable by insects, diseases such as typhus, malaria and sandfly fever claimed a large number of victims and interfered with the conduct of the War. The Swiss, who had recognized the great importance of DDT, secretly shipped a small quantity of the material to the United States; in December of 1942 the American Research Council for Insectology in Orlando (Florida) undertook a large series of trials which fully confirmed the Swiss findings. The war situation demanded speedy action. DDT was manufactured on a vast scale whilst a series of experiments determined methods of application. Particularly energetic was General Fox, Physician-in-Chief to the American forces.

In October of 1943 a heavy outbreak of typhus occurred in Naples and the customary relief measures proved totally inadequate. General Fox thereupon introduced DDT treatment with total exclusion of the old, slow methods of treatment. As a result, 1,300,000 people were treated in January 1944 and in a period of three weeks the typhus epidemic was completely mastered. Thus, for the first time in history a typhus outbreak was brought under control in winter. DDT had passed its ordeal by fire with flying colours.
By the late 1950's it became apparent that extensive use of DDT to control insects leads to its accumulation in the environment. This, in turn, leads to its concentration in the tissues of some animals, such as fish. The long term build up of DDT causes illness and death and it was finally banned in most countries in the 1970's.

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