A collaborative work between the Institut Pasteur du Cambodge and the Institut Pasteur du Laos, from the Pasteur Network, with the French National Research Institute for Sustainable Development (IRD) and the French Agricultural Research Centre for International Development (Cirad), demonstrates the future impacts of human-induced climate change on public health, This study highlights the threat of a significant increase of mosquito densities, a potential vector for numerous infectious diseases in South-East Asia. This study, carried out in the framework of the Ecomore 2 project, has been published in Environmental Health Perspective.
Dengue is an emerging infectious disease, transmitted by mosquitoes, that is affecting more and more people worldwide. Aedes aegypti and Aedes albopictus, the dengue vectors, are prone to expand due to climate change. Human populations could be increasingly exposed to potential outbreaks. In South-East Asia, where dengue is endemic, data on these mosquitoes were gathered by the entomology units of the Institut Pasteur du Cambodge and the Institut Pasteur du Laos, both members of the Pasteur Network.
Conducted in the framework of Ecomore 2 and other projects, this study relies on data collected by Sébastien Marcombe from the Institut Pasteur du Laos and by Sébastien Boyer at the Institut Pasteur du Camboge, together with other literature data on the occurrence of these two species in South-East Asia.
Data on presence, seasonality, and dynamics of Ae. aegypti & Ae. albopictus were analyzed regarding land-use, topography, and climate. Two IRD research units led the mathematical modelling and spatial analyses, first to model their distribution over the region and, second, to assess the impact of the prospective climatic scenarios (nine CMIP6 climate models) on their future distribution. The results show that, by the end of this century, Ae. aegypti and Ae. albopictus densities will respectively increase up to 46% and 25% in South-East Asia due to predicted temperature growths. Moreover, climate mitigation measures are unlikely to significantly moderate this expansion.
The maps resulting from these models are freely accessible on the Ecomore II Climate Platform. Users of the platform can observe the impact of different climate change models and scenarios on the evolution of the distributions of Aedes populations. These results provide further evidence that human-induced climate changes will impact ecosystems and public health.
For more information:
Predicting the Effects of Climate Change on Dengue Vector Densities in Southeast Asia through Process-Based Modeling
Environmental Health Perspective, December 2022.
Lucas Bonnin*, Annelise Tran, Vincent Herbreteau, Sébastien Marcombe, Sébastien Boyer, Morgan Mangeas, and Christophe Menkes.
Ecomore website: https://ecomore.org/2023/02/02/the-evolution-of-dengue-vectors-densities-faced-with-climate-change-in-south-east-asia/
Leo Lit Man Poon, from the Hong Kong University (HKU)- Pasteur Research Pole, member of the Pasteur Network, was awarded the Pasteur Network LP200 Prize, a special prize in commemoration of the 200th anniversary of the birth of Louis Pasteur at a ceremony organized by the Institut Pasteur (Paris) on Thursday, January 26th, 2023. This prize is part of a set of 5 prizes awarded by the Institut Pasteur in the framework of the bicentenary with the support of the Carlsberg Foundation that funded the total Prize amount of € 200,000.
To celebrate the bicentenary of Louis Pasteur’s birth, a series of five prestigious scientific prizes have been created by the Institut Pasteur in 2022. The prizes award for achievements that capture the Pasteur ethos, or “l’esprit Pasteur”, in the fields of biomedical research, public health, or innovation. Among them, one was dedicated to the Pasteur Network: the Pasteur Network LP200 Prize.
The International Jury presided over by Pascale Cossart, Professor at the Institut Pasteur and honorary perpetual secretary of the French Academy of Sciences, with the Nobel Prize in Physiology or Medicine Françoise Barré-Sinoussi (2008) and the Nobel Prize in Chemistry Emmanuelle Charpentier (2020), chose Leo Lit Man Poon as laureate. He received the prize from Françoise Barré-Sinoussi.
“This award recognizes the essential contributions of Prof. Poon’s to preparedness, research, collaborations, and commitment to the Pasteur Network, especially during the COVID-19 pandemic. It Pr. Poon embodies Louis Pasteur’s vision of science without borders”.
Rebecca F Grais, Executive director of the Pasteur Network
Leo Poon is a professor in the School of Public Health of the Li Ka Shing Faculty of Medicine, the University of Hong Kong as well as co-director of the HKU-Pasteur Research Pole, member of the Pasteur Network. He is a virologist and public health scientist dedicated to studying emerging viruses such as influenza viruses and coronaviruses.
Thus far, he has published about 300 peer-reviewed articles, with an H-index of 93. Since 2005, Leo has been in the Top 1% of most cited scientists and highly cited researcher since 2015. In 2022 Leo was named one of the Top 1,000 scientists by research.com.
Alongside, Leo Poon also serves as an expert in different working groups in international organization, such as the WHO, the WOAH and the Food and Agriculture Organization of the United Nations (FAO), for controlling emerging infectious diseases.
“There are so many great people who work together to combat infectious diseases. It is my honor to work with them to improve public health. Two centuries later, the spirit of Louis Pasteur still contagious”.
Leo Lit Man Poon, co-director of the HKU-Pasteur Research Pole, member of the Pasteur Network
Beside the Pasteur Network Louis Pasteur Bicentenary Prize, this series rewarded one head of senior Institut Pasteur scientist, Arnaud Fontanet, one head of junior Institut Pasteur scientist, Mélanie Hamon, and two alumni of the Institut Pasteur, Bruno Canard and Serge Mostowy, respectively with the Senior Alumni Louis Pasteur Bicentenary Prize and the Junior Alumni Louis Pasteur Bicentenary Prize and the Pasteur Alumni Louis Pasteur Bicentenary Prizes.
For more information:
Read the biography of Leo Poon on HKU- Pasteur Research Pole website: https://www.hkupasteur.hku.hk/copy-of-poon-lab
Read the news on HKU – Pasteur Research Pole website: https://www.hkupasteur.hku.hk/post/the-pasteur-network-lp200-prize-awarded-to-leo-poon
Read the news on the Institut Pasteur website: https://www.pasteur.fr/en/research-journal/news/louis-pasteur-bicentenary-prize-five-scientists-rewarded
Listen to the podcast (Nature Biotechnology): https://bioengineeringcommunity.nature.com/posts/podcast-creative-grit-episode-2
Recently, three new directors have taken up their positions within the Network.
In Canada, David Chatenet has taken over as Director of the Armand-Frappier Santé Biotechnologie Research Centre at the Institut National de Recherche Scientifique (INRS).
In Brazil, following the appointment of Nísia Trindade Lima as head of the Ministry of Health, Mario Moreira, former Executive Director, became Acting President of Fiocruz.
In Korea, Youngmee Jee, has been appointed as the new head of the Korea Disease Control and Prevention Agency (KDCA). The former Administrative Executive Director, Byungkwon Lim, has taken over as CEO of the Pasteur Institute of Korea.
As the Pasteur Network continues to evolve, it regularly offers new positions to its members. The Network’s job offers are available and can be consulted on the career page.
Due to globalization and the spread of vectors such as mosquitoes, dengue disease is an increasing burden on public health across the world. Rapid detection of vector species, and prevention of their establishment can be achieved by tracking vectors. Scientists from the Pasteur Network, based at the Institut Pasteur de Nouvelle-Calédonie, the Institut Pasteur du Camboge, the Institut Pasteur du Laos and the Institut Pasteur de Madagascar, published an article in Plos One showing MALDI-TOF MS as a promising tool that could be used for an international surveillance of mosquito vectors of arbovirus.
A public health burden
Dengue virus is a pathogen transmitted to humans by vector mosquitoes. It causes mostly mild illness or flu-like syndromes. However, repeated infections are known to cause severe and potentially fatal clinical forms, called severe dengue.
Due to globalization, the geographical distribution of mosquitoes known to transmit the dengue virus is increasing, particularly in non-endemic regions. Dengue global incidence has increased eightfold in the last decades with an estimation of 390 million infected individuals per year across the world. The dispersal risk highlights the need to improve vectors surveillance, ensuring rapid detection of introduced vector species and prevention of their establishment in new areas. The surveillance relies on accurate species identification of the vectors. Aedes aegypti and Aedes albopictus, as known as the tiger mosquito, which have a worldwide distribution, are the well-known vectors of dengue virus. However, in the Pacific region, at least 9 other species belonging to the Scutellaris Group mosquitoes are present and are confirmed or potential vectors of dengue virus.
MALDI-TOF MS for a global surveillance of mosquitoes
Mosquitoes of the Scutellaris Group are morphologically similar and pre-existing DNA sequence information is often unavailable. Therefore, scientists from the Pasteur Network, assessed the use of Matrix-Assisted Laser Desorption Ionization Time-Of-Flight Mass Spectrometry (MALDI-TOF MS) in identifying these dengue virus vector species. MALDI-TOF MS is a method that generates protein spectra specific for each species.
Field-mosquitoes belonging to 8 species from 6 countries in the Pacific, Asian and Madagascar, were included in this study carried out by the Institut Pasteur de Nouvelle-Calédonie, in collaboration with the Institut Pasteur du Cambodge, Institut Pasteur du Laos and the Institut Pasteur de Madagascar. Analysis provided evidence that a MALDI-TOF database created using mosquitoes from the Pacific region allowed suitable identification from the other regions. This technic was as efficient as the DNA sequencing method in identifying mosquito species. Indeed, for the most cases, an exact species identification was obtained for all individual mosquitoes even for morphologically and phylogenetically closely related species. Ultimately, these findings highlight that the MALDI-TOF MS is a promising tool that could be used for a global comprehensive arbovirus vectors surveillance.
For more information:
MALDI-TOF MS: An effective tool for a global surveillance of dengue vector species
Plos One, October 2022.
Antsa Rakotonirina*, Morgane Pol, Fara Nantenaina Raharimalala, Valentine Ballan, Malia Kainiu, Sébastien Boyer, Sosiasi Kilama, Sébastien Marcombe, Sylvie Russet, Emilie Barsac, Rama Vineshwaran, Malia Kaleméli Selemago, Vincent Jessop, Geneviève Robic, Romain Girod, Paul T. Brey, Julien Colot, Myrielle Dupont-Rouzeyrol, Vincent Richard, Nicolas Pocquet
 Ae. aegypti, Ae. albopictus, Ae. polynesiensis, Ae. scutellaris, Ae. pseudoscutellaris, Ae. malayensis, Ae. futunae and Culex quinquefasciatus
On December 09th, 2022 was held the 2021-2022 Institut Pasteur PhD Graduation Ceremony. Three graduates represented Pasteur Network: Dr Habib for the Institut Pasteur de Madagascar, Dr Lyu for the HKU-Pasteur Research Pole and Dr Modiyinji for the Pasteur Center in Cameroon. After the introductory speech of the guest of honor, Prof. Ugur Sahin, Professor of Translational Oncology and Immunology at the University of Mainz and CEO of BioNTech, all had a few minutes to present their background.
Dr. Azimdine Habib
“Always have a goal in life and give yourself all the means to achieve it. Never be afraid of failure but learn from it to move forward”
Dr. Azimdine Habib is originally from the Comoros Islands where he obtained his bachelor’s degree in Life Sciences in 2012. His master’s degree in Fundamental and Applied Biochemistry, option Biochemistry, Biodiversity and Health has brought him to Madagascar. He joined the Institut Pasteur de Madagascar during his second year in the bilharzia laboratory. In 2016, he was recruited as a laboratory technician in the experimental bacteriology unit. In 2017, he began his PhD under the supervision of Dr. Jean-Marc Collard. His thesis explores the link between the composition of the intestinal microbiota and intestinal parasites, especially in children with malnutrition. As part of the “My Thesis in 180 seconds” competition, organized by the Institut Pasteur de Madagascar, Azimdine Habib presented his thesis to a non-scientific audience and won first place in the 2nd edition. He then defended his thesis in December 2021. In October 2022, he joined the BIOMICS technology platform of the Institut Pasteur, also a member of the Pasteur Network, as a research engineer where he is interested in next generation sequencing.
Dr. Huibin Lyu
“Practice is the sole criterion for testing truth”
Dr. Huibin Lyu, aka Tomas, has started his research journey at the Guangdong University of Technology in China, investigating the anti-bacterial and anti-tumor functions of Curcumin. This first encounter with research has spurred him to begin his second Master regarding virology and immunology at Guangzhou Medical University. Especially, he focused on cross-reactive monoclonal antibody screening against the influenza A virus. Under a Doctoral Grants Calmette & Yersin scholarship, he joined the HKU-Pasteur Research Pole, member of the Pasteur Network, to carry out his Ph. D. in Prof. Roberto Bruzzone and Dr. Chris Mok’s group. His initial Ph. D. research proposal was a continuation of his master’s degree and focused on the antibody response after the first influenza infection in the newborn and the specialization of the immune system in the mouse model. In response to the Covid-19 pandemic, Dr. Lyu shifted his focus to another virus, SARS-CoV-2, and contributed to a better understanding of the immune response to this virus. In September 2022, he defended his dissertation on the cross-reactions of the immune system to SARS-CoV-2 in humans and mice. Dr. Lyu is now a post-doctoral fellow at the University of Illinois Urbana-Champaign where he is working to identify signatures of human antibodies against different pathogens.
Dr. Abdou Fatawou Modiyinji
“Science has no homeland”
Dr. Abdou Fatawou Modiyinji completed his studies at the Faculty of Sciences of the University of Yaoundé 1 in Cameroon. In 2012, he obtained his bachelor’s degree in Biology of Animal Organisms. He continued with a master’s degree in Parasitology and Ecology which he obtained in 2015. He then carried out a PhD at the Department of Animal Biology and Physiology and the Centre Pasteur du Cameroun, a member of the Pasteur Network. His thesis, the first study of its kind in Cameroon, focused on hepatitis E among human and animal populations in the country. In addition to characterizing the genotypes of the hepatitis E virus in humans, it highlighted a high seroprevalence of the virus in both populations suggesting an interspecies transmission of the hepatitis E virus in Cameroon. Abdou Fatawou Modiyinji, author of several publications during his thesis, defended his thesis in July 2022. He is now studying enteroviruses as a post-doctoral researcher at the Pasteur Center in Cameroon.
Some pathogens present asymptomatic forms that complicate the study of their transmission dynamics and their determinants. Researchers from the Pasteur Network based at the Institut Pasteur de la Guyane and the Institut Pasteur (Paris), in collaboration with the Cayenne Hospital, have studied the atypical incidence of Q fever in Guyana. Their work, published in The Lancet Regional Health – Americas, estimates a high risk of infection in the general population. They highlight the important role of livestock in transmission.
Q fever, a zoonosis with limited symptoms
Q fever is a zoonosis caused by Coxiella burnetii, a bacterium that infects a majority of mammals in most parts of the world. Ruminants, the main source of human infection, can excrete the bacteria in calving products, feces, vaginal secretions, and milk. Transmission is mainly by airborne route and is manifested by clinical signs in humans in only 40% of cases. If present, clinical signs are generally flu-like and non-specific, but may sometimes be associated with pneumonia, hepatitis and, more rarely, with more severe symptoms, especially in patients with comorbidities. 60% of reported cases worldwide have been identified during epidemics centered around farms or slaughterhouses infected with the bacterium.
French Guiana, a special case
The French Guiana population has the highest incidence of Q fever in the world. 24% of hospitalized cases of community-acquired pneumonia are attributed to this region. Most of the patients hospitalized came from metropolitan France and lived in the urbanized area of Cayenne and its suburbs. However, the classic risks of exposure (slaughterhouse or livestock in the vicinity) were not found among the diagnosed cases. As no wild reservoir was clearly identified, previous studies considered transmission by livestock to be unlikely.
The atypical nature of its transmission combined with a high proportion of asymptotic cases has made it difficult to understand the epidemiology and determinants associated with Q fever in French Guyana. In order to better understand its transmission dynamics and to orient public health intervention strategies, researchers from the Pasteur Network and infectious diseases specialists from the Cayenne Hospital Center collaborated to conduct a serological survey of 2,700 individuals representative of the different communities in French Guiana.
Domestic livestock as a vector of the disease
The authors modelized serological data classified by age in order to reconstruct the history of the circulation of the bacterium in the different regions of the territory. Their results show a constant circulation of C. burnetii throughout French Guiana with an estimated annual number of cases of 579. 9.6% of the population tested had already been infected and middle-aged men and individuals living near livestock. Analysis of the data identified an epidemic that occurred between 1996 and 2003 in the communes of Remire and Matoury. This epidemic, which infected 10% of the population, explains the high proportion of people carrying antibodies against C. burnetii in the urban area of Cayenne Island.
This collaborative work has made it possible to model for the first time the transmission dynamics of Q fever in French Guiana. The highlighting of the role of domestic livestock in a context of important transmission of the bacterium argues for the reinforcement of surveillance and risk reduction activities in French Guiana’s livestock farms and underlines the interest of a “One Health” approach combining a human, animal, and environmental component.
Serological surveys, essential tools
This type of large-scale serological survey has already been conducted in Bangladesh for dengue and for Chagas disease in Colombia. It allows the study of a wide range of factors contributing to disease control such as pathogen circulation patterns, immunity levels related to vaccination or previous infection or potential areas of emergence. This multi-factorial approach with a very positive cost/benefit ratio (cost of analysis versus amount of data generated/output) is a very valuable tool to promote to public health agencies and authorities.
It is proposed that this methodology could be reused by the members of the Pasteur Network in the framework of a phase 3 of the ECOMORE project involving Cambodia, Laos, Philippines, and Vietnam, in collaboration with the Institut Pasteur in Paris, for which funding is still being sought. Indeed, its use would improve the understanding of the circulation history of a multitude of pathogens (viruses, bacteria, and parasites), representing a public health issue for these countries, and of the epidemiology of their associated diseases in order to propose appropriate interventions to the authorities of these countries.
For more information:
Transmission dynamics of Q fever in French Guiana: A population-based cross-sectional study
The Lancet Regional Health – Americas, October 2022.
Sarah Bailly†, Nathanaël Hozé†, Sylvie Bisser, Aurélien Zhu-Soubise, Camille Fritzell, Sandrine Fernandes-Pellerin, Adija Mbouangoro, Dominique Rousset, Félix Djossou, Simon Cauchemez‡, Claude Flamand‡*.
†, ‡These authors contributed equally to this work.
DOI : https://doi.org/10.1016/j.lana.2022.100385
From October 24th to October 28th, Pasteur Network’s scientists had the opportunity to promote their results pursued in the framework the ECOMORE 2, in the 20th International Congress for Tropical Medicine and Malaria (ICTMM) in Bangkok, Thailand. The event allowed to highlight several activities of the project by three Pasteur Network members: the Institut Pasteur du Cambodge, the Institut Pasteur du Laos and the National Institute of Health and Epidemiology in Vietnam. Vector management for dengue, dengue outbreak simulator and, seroprevalence and serovar distribution of leptospirosis are some examples of the topics discussed.
The 20th International Congress for Tropical Medicine and Malaria (ICTMM) was held from October 24 to October 28th in Bangkok, Thailand. This five-day congress gathered key players in the sector to unravel the latest and challenging news surrounding tropical medicine, infectious diseases, neglected diseases, malaria and zoonoses. During the opening ceremony, Associate Prof. Pratap Singhasivanon, Chairman of ICTMM, stressed that these group of diseases still affect the poorest and most vulnerable populations. As climate change-induced temperatures intensify, he pointed out the pressing needs to improve current preventive measures and to further invest in the fight against these diseases. Several Pasteur Network scientists involved in ECOMORE 2, which notably aims to evaluate the impact on climate change on local health population, has shared it results through plenary sessions, topic keynotes, symposia, oral and poster presentations.
The integrated vector management for dengue
On October 25th, Dr. Sebastien Boyer, Head of Medical Entomology Unit at the Institut Pasteur du Cambodge, member of the Pasteur Network, was invited to expose his work in the “vectors, vector control and vector-borne diseases” session. He presented the results of the integrated vector management for dengue vectors in schools with entomological and epidemiological approaches. While a decrease of the core dengue virus vector, Aedes aegypti, density was observed, and toilets were detected as the main breeding sites in schools, the integrated vector control did not decrease the dengue transmission in schools and in surrounding communities. This could be explained by the fact that households are usually the significant spot of transmission.
The design of the dengue outbreak simulator
The next day, Damien Philippon, representing the Institut Pasteur du Laos, had the opportunity, during the “epidemiology and transmission dynamics of dengue” session, to explain the methods for the design of the dengue outbreak simulator, a tool for predicting dengue incidence in Vientiane prefecture. Various data (GIS, epidemiological, mobility, weather, census and land cover) were aggregated into weekly data as input of the model. Although the model is complex as available datasets do not cover the same time frames and do not overlap, its precision allows the prediction of absence or presence of dengue. At present, it does not concern incidence. In near future, more tuning of the model could be performed to increase its precision.
The seroprevalence and serovar distribution of leptospirosis
Prof. Le Thi Phuong Mai, Head of Public Health at National Institute of Health and Epidemiology, one of the three Pasteur Network members in Vietnam, presented in the form of a poster, the results of the multi-center study on seroprevalence and serovar distribution of leptospirosis among healthy people in Vietnam. 600 persons in total were enrolled, from Thai Bing (North), Ha Tinh (Center) and Can Tho (South) in 2019 for testing. A relatively high rate of leptospira seropositivity was reported among this general population, with most seropositive people being farmers. Moreover, the four predominant serovars circulating were Hebdomadis, Pomona, Saxkoebing and Panama. It has been recommended to initiate health promotion program and trainings in using personal protective equipment, among farmers to reduce the risk of infection.
All in all, this congress, which occurs every four years, happened to be a perfect regional showcase to highlight the results of the Pasteur Network scientists dedicated to ECOMORE 2.
For more information:
The article published on ECOMORE website: https://ecomore.org/2022/11/14/ecomore-2-results-promoted-at-the-20th-ictmm-congress/
The article published on the Institut Pasteur du Cambodge website: https://www.pasteur-kh.org/2022/11/04/20th-international-congress-for-tropical-medicine-and-malaria-held-in-bangkok-from-24-to-28-october-2022/
Monkeypox virus (MPXV) is a neglected tropical pathogen whose recent emergence has accelerated its study. In this context, Pasteur Network researchers have developed rapid MPXV diagnostic tests that can be viewed by the naked eye in less than 30 minutes, and are as consistent as the current PCR-based nucleic acid test used for MPXV diagnostics. This new diagnostic tool will contribute to the control and prevention of MPXV epidemics.
In May 2022, outbreaks of monkeypox virus (MPXV) were reported simultaneously in Europe, North America and South America, outside the virus-endemic regions of Africa. Pasteur Network researchers collaborated to develop and validate tests for the rapid detection of MPXV. These newly designed tests can produce reliable fluorescence or lateral flow results on a strip in 20 to 30 minutes. Led by the teams of Emmanuel Nakouné (Institut Pasteur de Bangui) and Nicolas Berthet and Gary Wong (Institut Pasteur de Shanghai), the study presenting the results of these rapid diagnostic tests was published in the journal Viruses.
The tests are based on isothermal amplification of a targeted region of the virus genome, and are based on recombinase with or without CRISPR/Cas12. The tests gave consistent results with the reference molecular test, PCR in real time, for the 19 clinical samples used to validate the assay. In addition, the tests were specific and did not cross-react with other pox viruses, such as vaccinia.
MPXV, a neglected tropical pathogen, is closely related to smallpox, a disease that has been eradicated in humans since the 1980s. Although MPXV epidemics are regularly reported in Africa among the poorest communities, it remains understudied, even after the first MPXV epidemic was reported outside the endemic areain the USA during 2003. Rapid, sensitive and specific detection of MPXV is essential to inform health authorities of suspected cases as soon as possible, in order to monitor epidemic developments. These results therefore provide a point-of-care platform for the early diagnosis of potential MPXV cases, and will contribute to the prevention and control of current and future MPXV epidemics.
For more information:
Article from the Institut Pasteur de Bangui (in French)
Development and Characterization of Recombinase-Based Iso-thermal Amplification Assays (RPA/RAA) for the Rapid Detection of Monkeypox virus
Viruses, September 2022.
Lingjing Mao, Jiaxu Ying, Benjamin Selekon, Ella Gonofio, Xiaoxia Wang, Emmanuel Nakoune, Gary Wong*, Nicolas Berthet*
* Corresponding authors.