Yeya Tiemoko Touré, a researcher in medical entomology and former professor of cell biology and genetics from Bamako, Mali, is the winner of 2018 TWAS-C.N.R. Rao Award for scientific research.
Using cytogenetics and molecular genetics techniques, Touré has identified mosquito populations of Anopheles gambiae – the malaria vector – with different genetics settings. His findings have important implications in the fight against Anopheles, whose bite can also spread another disease called filariasis by injecting disease-causing roundworms into the human body.
"I'm honoured for this prize – it comes as recognition of my career-long efforts to contain malaria, which poses a severe burden to Mali," Touré said after winning the honour. "I'm not actively involved in research, now. I have passed the laboratory to younger scientists. But I'm still active as an adviser to the new generations of researchers, and this prize strongly motivates me to be even more present in leading young scholars."
The announcement was made on 27 November during the 28th TWAS General Meeting, held this year in the Academy's headquarters city of Trieste, Italy. The C.N.R. Rao Award features a cash award of USD5,000 generously provided by Rao, a distinguished Indian chemist who was a TWAS Founding Fellow and former president of the Academy.
A native of Gao, Mali, Touré earned his PhD in 1979 in medical entomology from the Centre Pédagogique Supérieur in Bamako and a 1985 Doctorat d’Etat ès Sciences in life sciences from Université de Droit, d'Economie et des Sciences d'Aix-Marseille III in France.
Touré, now retired, has had a long and very productive career. In 1981 he started as a professor of cellular biology and genetics, and a researcher in medical entomology at the faculty of medicine and pharmacy, University of Bamako in the capital city. From 1987 to 1991 he was the director general of the Centre National de la Recherche Scientifique et Technologique (CNRST), in Bamako.
Most notably, from 2001-2014 he managed the vector biology and control unit of the Special Programme for Research and Training in Tropical Diseases (TDR), a global programme of scientific collaboration hosted at the World Health Organization (WHO) and co-sponsored by the United Nations Children’s Fund (UNICEF), the United Nations Development Programme and the World Bank.
Due to his work at TDR, several methods for controlling vector-borne diseases like malaria, dengue, Chagas disease, and human African trypanosomiasis are now widely used. And thanks to his investigations, a huge amount of new information is today available on the genetics of Anopheles gambiae, the mosquito that transmits human malaria by injecting a parasite called Plasmodium when it feeds on human blood.
The "weird" roots of discovery
In a lecture prepared for the TWAS meeting, Touré explained that malaria is the primary cause of mortality in Mali, especially among children under 5. According to the national health system, in 2015 Mali recorded about 2.4 million clinical cases in health facilities. And the disease is not subsiding, because of the increasing rate of resistance developed by mosquitoes towards insecticides and by the plasmodium towards antimalarial drugs.
Current prevention and treatment measures – which are good but not always enough – include insecticide-treated mosquito nets, indoor residual spraying of insecticides, precise diagnosis and rapid treatment with artemisinin-based medications as well as preventive treatment of pregnant women. Important information, as it turned out, was hidden in the mosquito's DNA.
"Early in the 80s we realized that there was a weird heterogeneity in spatial and seasonal distribution of vectors and in transmission of malaria, likely related to different types of mosquitoes," Touré said. This prompted him and his group to use cytogenetics and molecular methods for population genetics analysis of the mosquitoes.
The findings were surprising. Touré's team found three chromosomal forms named Bamako, Savanna and Mopti, apparently genetically different Anopheles gambiae populations, which in the end turned out to be only two molecular forms designated as S (for Bamako/Savanna) and M (for Mopti).
Interestingly, they live in slightly different areas, have remarkable differences in spatial and seasonal distribution and have different malaria transmission patterns. "Bamako/Savanna prefers humid areas in the South of Mali, breeds in rain-dependent spots and along rivers, and has its transmission peak during full rainy season," explained Touré. "Mopti form lives in a wide range of ecological areas from South humid to North dry zones, breeds in flooded areas and in rice fields, and transmits the disease's parasite at the very beginning, during and mostly at the end of the rainy season."
This has had immediate and important positive consequences on control measures, applied in collaboration with the National Malaria Control Programme, through selective strategies such as targeting the time when transmission is higher, or specific mosquito breeding sites.
Bold progress attracts young researchers
This was not the only result. "The huge amount of information that we were able to produce has helped attract many young scientists to medical entomology, a field almost ignored until several years ago," Touré says. In addition, many facilities have been created that are now further supporting this scientific area.
And in a domino effect, this also helped training a lot of researchers from West, Central and East Africa on the importance of Anopheles species complexity.
Malaria's vector is not the only field where Touré proved his commitment and insight. He also helped create the International Glossina Genome Initiative (IGGI), a consortium that sequenced and published the genome of Glossina morsitans, a variety of tsetse fly that transmit trypanosomiasis, or sleeping sickness.
Near his retirement, he led a new TDR unit called vectors, environment and society research, that established a partnership with Canada’s International Development Research Centre (IDRC). They carried out a four-year research project on vector-borne diseases and the way they adapt to climate change in Africa.
Under his leadership and guidance for a new generation of scientists, several hundred people have received training on bioinformatics, functional genomics applied to vectors, as well as biosafety.
Touré retired from WHO in July 2014 and from the Malian civil service in January 2018. Today he continues to serve as a member of scientific and technical committees for WHO and other institutions in Africa, Europe and the United States and as a member of the Malian Academy of Sciences.
Supporting capacity-building is among his continuing goals. And retirement doesn't mean he has stopped working. "I felt it was right to pass the lab to new generation scientists," he explained. "So now I can be very active as an adviser."
TWAS-C.N.R. Rao Award for Scientific Research
The prize, named after TWAS Founding Fellow and former president C.N.R. Rao, includes an award of USD5,000 generously provided by Professor Rao. It is designed to honour TWAS Fellows from the Least Developed Countries (LDCs) who have made significant contributions to global science.
About C.N.R. Rao
Rao is a globally renowned chemist and science policy leader. He has chaired the Scientific Advisory Council to the Prime Minister of India. He is currently the National Research Professor, Linus Pauling Research Professor and Honorary President of Jawaharlal Nehru Centre for Advanced Scientific Research in Bangalore, India, which he founded in 1989. He is a Founding Fellow of TWAS, and served as the Academy's president from 2000 to 2007, establishing himself as a driving force who made great contributions to the success of the Academy. Rao also has played a central role in many governmental agencies and on committees in India.