Walborg Susanna Thorsell (12 February 1919 – January 2016) was a Swedish scientist who performed research mainly on

mosquito Mosquitoes, the Culicidae, are a Family (biology), family of small Diptera, flies consisting of 3,600 species. The word ''mosquito'' (formed by ''Musca (fly), mosca'' and diminutive ''-ito'') is Spanish and Portuguese for ''little fly''. Mos ...

es and mosquito repellents.

Education

Thorsell defended her thesis for her

doctorate A doctorate (from Latin ''doctor'', meaning "teacher") or doctoral degree is a postgraduate academic degree awarded by universities and some other educational institutions, derived from the ancient formalism '' licentia docendi'' ("licence to teach ...

veterinary medicine Veterinary medicine is the branch of medicine that deals with the prevention, management, medical diagnosis, diagnosis, and treatment of disease, disorder, and injury in non-human animals. The scope of veterinary medicine is wide, covering all a ...

at the Swedish Veterinarian Institute in 1967, and was a

docent The term "docent" is derived from the Latin word , which is the third-person plural present active indicative of ('to teach, to lecture'). Becoming a docent is often referred to as habilitation or doctor of science and is an academic qualifi ...

in experimental

parasitology Parasitology is the study of parasites, their host (biology), hosts, and the relationship between them. As a List of biology disciplines, biological discipline, the scope of parasitology is not determined by the organism or environment in questio ...

Research

Thorsell started her studies on mosquitoes while working at the

Swedish National Defence Research Institute Swedish National Defence Research Institute (, FOA) was a Swedish government agency in defense research existing from 1945 to 31 December 2000. It was amalgamated with the National Aeronautical Research Institute (FFA) into the Swedish Defence ...

(FOA). At that time claims circulated, from both the United States and the Soviet Union, that the other part was conducting experiments with malaria mosquitos in relations to

biological warfare Biological warfare, also known as germ warfare, is the use of biological toxins or Pathogen, infectious agents such as bacteria, viruses, insects, and Fungus, fungi with the intent to kill, harm or incapacitate humans, animals or plants as an ...

. The Swedish military therefore felt it necessary to develop a mosquito repellent, especially for malaria mosquitoes, to be used by Swedish soldiers. The existing repellents were either not efficient enough or had unwanted side effects, so Thorsell and her group of researchers at FOA began looking for a better agent. The substance ''diethylamide'' proved to be an excellent repellent for both malaria mosquitoes and ordinary Swedish forest mosquitoes. But in its unmodified form, it is water-soluble and was washed away by the sweat when applied on the soldiers. Thorsells' solution to this was to add the same

functional group In organic chemistry, a functional group is any substituent or moiety (chemistry), moiety in a molecule that causes the molecule's characteristic chemical reactions. The same functional group will undergo the same or similar chemical reactions r ...

s as in ''diethylamide'' to

mandelic acid Mandelic acid is an aromatic alpha hydroxy acid with the molecular formula C6H5CH(OH)CO2H. It is a white crystalline solid that is soluble in water and polar organic solvents. It is a useful precursor to various drugs. The molecule is chiral. The ...

. This resulted in a mosquito repellent, called ''DEMIDEX'', that was manufactured during a number of years. ''DEMIDEX'' was more efficient than the American

DEET ''N'',''N''-Diethyl-''meta''-toluamide, also called diethyltoluamide or DEET (, from DET, the initials of di- + ethyl + toluamide), is the oldest, one of the most effective, and most common active ingredients in commercial insect repellents. ...

, which was and still is the most common active ingredient in insect repellents. After retiring from FOA, Thorsell continued her research on mosquito repellents at the Department of Zoology at

Stockholm University Stockholm University (SU) () is a public university, public research university in Stockholm, Sweden, founded as a college in 1878, with university status since 1960. With over 33,000 students at four different faculties: law, humanities, social ...

. That research resulted in the repellent ingredient ''IXNIX''. She died in January 2016 at the age of 96.

Honours

A family of bacteria, ''

Thorselliaceae Thorselliaceae is a family of bacteria belonging to the class Gammaproteobacteria and it was first described in February 2015. It is not assigned to an order. The family consists of four species in two genera. The bacteria are Gram-negative and r ...

'', found in

vector Vector most often refers to: * Euclidean vector, a quantity with a magnitude and a direction * Disease vector, an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematics a ...

mosquitoes, mainly with vectors of

malaria Malaria is a Mosquito-borne disease, mosquito-borne infectious disease that affects vertebrates and ''Anopheles'' mosquitoes. Human malaria causes Signs and symptoms, symptoms that typically include fever, Fatigue (medical), fatigue, vomitin ...

, has been named after Thorsell. The family contains the genus '' Thorsellia'' of which three species are known so far.

Bibliography

A selection. * ''Krigsepidemiologi och hälsovård för totalförsvaret: dokumentation från FOA informationsdag, översiktsdag, Stockholm, 1982-05-05'' (Warfare epidemiology and health care within the Swedish total defence : documentation from the FOA conference, Stockholm, 82-05-05) 1983 * ''Människans fysiska tålighet i brandmiljö: brandgaser och rök'' (Man's physical tolerance in fires: fumes and smoke) 1984 * ''Människan och ohyran - bekämpningsmedel i Sverige förr och nu'' (Man and Vermin – pesticides in Sweden, past and present) 2001

Education

Research

Honours

Bibliography

References

Further reading