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RESEARCH

Medical Entomology Platform

The Medical Entomology Platform has been recently created at IPC, in 2015. This platform includes an insectary for rearing mosquito colonies (Anopheles, Culex and Aedes). A collection room for training and reference specimens is in progress.

RESEARCH

Medical Entomology Platform

The Medical Entomology Platform has been recently created at IPC, in 2015. This platform includes an insectary for rearing mosquito colonies (Anopheles, Culex and Aedes). A collection room for training and reference specimens is in progress.

The Medical Entomology Platform is managed by Sebastien BOYER (Medical Entomology Platform) under supervision of Didier FONTENILLE. The platform welcomes the Malaria Molecular Epidemiology Unit (Amélie VANTAUX) and Virology Unit (Veasna DUONG).

Staff is: Sony YEAN, Kimhuor SUOR, Moeun CHHUM (Medical Entomology), Borin PENG, Chhoueth NEUNG, Senglong PANG (Virology), Reingsey SAMRETH (Malaria Molecular and Eakpor PIV (Malaria Molecular Epidemiology).

The platform is implicated in several projects from Malaria, Virology and Epidemiology Units:

Malaria: Role of vectorial transmission on the evolution of Plasmodium falciparum artemisinin resistance: using in vitro gametocyte culture we will assess the infectivity of artemisinin-resistant and artemisinin-susceptible strains to the mosquito vector. PI: Amélie VANTAUX, Malaria Molecular Epidemiology Unit.

Lacanet project: The vector component of this project is to sample, to identify and to test for arboviruses, wild mosquitoes collected in Mondulkiri and Kompong Thom provinces. PI: Philippe DUSSART, Virology Unit

Japanese Encephalitis (JE): 2 projects aim to document the burden and the transmission of JE virus (SEAe projects, PI: Philippe DUSSART, Virology Unit, and ComAcross project, PI: Véronique CHEVALIER, Epidemiology & Public Health Unit). Diversity, dynamics and implication in JEV transmission of potential vectors (mainly Culex) are assessed within the ComAcross projects, in Kandal and Ta Khmau.

Zika Acip project: Study of vector competence and vertical transmission of ZIKAV in Cambodia Aedes spp. Mosquitoes. Co-PI: Veasna DUONG, Virology Unit.

Zikalliance: A Global Alliance for Zika Virus Control and Prevention. Belonging to an international consortium regrouping 53 partners, the project has 3 main objectives:

      • To determine the impact of Zika virus infection during pregnancy and short & medium term effects on newborns,
      • To retrace the natural history of Zika virus infection in humans and their environment in the context of other circulating arboviruses,
      • To built an overall capacity for preparedness research for future epidemic threats.

PI: Xavier DE LAMBALLERIE

Dengue: Ecomore 2 project, financed by AFD, aims to decode the mains anthropogenic and/or ecological mechanisms responsible for the emergence of infectious diseases. The finality of the project is to propose applicable intervention strategies. The project will last until 2018. PI: Sowath LY

Dengue: The Medical Entomology Platform in collaboration with Malaria Consortium study the insecticide resistance status of the main Dengue virus vector, Aedes aegypti. The actual tested insecticides are temephos, permethrin and Bacillus thuringiensis israelensis. Other control methods will be studied. PI: Sebastien BOYER

Chikungunya: WP2 of a PTR project. Evolution of chikungunya virus Caribbean strains in American and Asian mosquitoes. The objective of this WP is to identify naturally emerging variants during persistent infection of mosquitoes and predict the evolutionary trajectory of the Caribbean strain during natural transmission cycles. Since this strain first originated in Asia, its evolution in Asian mosquitoes will also be determined for comparison. Co-PI: Veasna DUONG, Virology Unit.

Projects

Ecomore 2 project is funded by the while PANIC project is financed by the European Union. The objective of the project was to determine if a successful integrated vector management (IVM) in localized areas could decrease the incidence of Dengue virus in communities in rural and peri-urban areas. In schools, the IVM was divided in 4 distinct interventions: 1) elimination of breeding sites with the help of students and their professors, 2) scientific animation in the school with education and sensitization of children, 3) the use of a bacterio insecticide (Bacillus thuringiensis israelensis) used as a larvicide in water jars and big reservoirs of water, and 4) use of an auto-dissemination insecticide (Pyriproxyfen) for the dissemination of insect growth regulator larvicide and spores of Beauveria bassiana for slowly killing adults. The principal expected outcome of the study was the number of dengue-like fever cases in the villages around schools.

We were able to observe if the focalized vector control methods were efficient. Entomological preliminary data during the second year, following interventions, showed a decrease of 50% of Aedes aegypti relative abundance in treated clusters compared to untreated ones. The latter showed an average relative abundance of Ae. aegypti similar to the first year. The difference for Ae. albopictus relative abundance was not significant between the two areas. Epidemiological data acquisition are still in progress: between May and 15 August 2018, 485 dengue-like syndromes were detected-320 in the control area and 165 in the treated area.

The results were shared with the MOH, Ministry of Education, Youth and Sport, and Ministry of Agriculture, Forestry and Fisheries in 2018, 2019 and 2020. The aim of the project is to propose an appropriate intervention strategy to the MOH. The project is scheduled to end in 2020.

Website: http://ecomore.org

The PREEMPT project aims to determine the mosquito species and virus families present in conserved biodiversity areas. The objectives will be to sample different areas, such as wildlife parks, high conservation areas, and nature parks in order to determine the presence of potential viruses. This work is coordinated with the Ministry of Environment and World Conservation Society in Cambodia.

In 2019, three sites were sampled during both dry and rainy seasons. Prek Taol Wildlife Sanctuary, located in Battambang Province is recognized as a main place for migratory birds in Cambodia. Peam Krasaop Wildlife Sanctuary, located in Koh Kong province, is a mangrove sanctuary. Virachey National Park located in Ratanakiri Province, is described as a primary forest hosting several monkey (macaca, gibbons) and large mammals species (bears, elephant, muntjac deer). An important diversity of mosquito species was observed in the three sampling sites with more than 32 mosquito species representing also a first description of their biodiversity in these areas, including the discovery of new mosquito species for the country. Finally, the mosquitos collected during Year 1 were sent to Institut Pasteur in Paris to determine the presence of virus in the different species.

Website: https://www.darpa.mil/program/preventing-emerging-pathogenic-threats

The objective of this project is to understand how the changing relationships between villages, forests and deforestation activities are affecting the mosquitos and viruses diversity and to develop a new method of diagnosis and an associated adapted surveillance program. We want to understand these issues through the vector “mosquito”, because of the in-depth knowledge it has, and the current major epidemic emergences due to mosquitos.

In addition, the current education system situation in Cambodia is alarming, as there is no University courses related to entomology, nor practical work applied to virology. For the public health needs of the country, the Institut Pasteur du Cambodge proposes through this project, to train entomologists in the field by a training in Medical Entomology, and also virologists for the national reference center for surveillance of arboviruses in Cambodia.

In 2019, 12 missions were realized for FSPI projects aiming 5 different areas in 5 different provinces, ie Pailin, Preah Vihear, Kampong Som, Battambang and Kampong Thom.

The diversity, distribution and seasonality of mosquito species in Phnom Penh is unknown. My team proposed to carry out a weekly follow-up during one year to fill this knowledge gap. We planned to study the dynamics of Dengue vectors in Phnom Penh. The relative abundance of the different species will be analyzed according to different meteorological parameters, and the different types of urban environment surrounding pagodas.

The field missions in 40 sample points in Phnom Penh began in 2019. The sampling is realized twice a week in Phnom Penh. The objective will be to evaluate the dynamics, and the risk associated with the potential presence of mosquito vector species.

This work is realized in collaboration with the Ministry of Cults and Religion.

The second steering committee of the project Ecomore 2 was held in Hanoi (14-17 January 2019), and the 1st national Stakeholders meeting was held in Lipa city in Philippines (27 February 2019). An international meeting with IP Laos, IP Hong-Kong, IP Shanghai on outbreak preparedness and readiness in the Lancang Mekong cooperation region was organized in Kunming, China (May 2019). An exploratory mission was realized in Myanmar in 2019 to meet the NHL partner for entomological collaborations. The 3rd steering committee of Ecomore2 was in Vientiane (Lao PDR), end of November 2019. Finally, a Leishmaniosis meeting for developing an international consortium was organized by IP Paris in Bangkok in November 2019.

Previous Research Projects

Japanese encephalitis virus (JEV) remains the leading cause of acute encephalitis in East and South Asia. Culex tritaeniorhynchus is the main vector of Japanese encephalitis in rural settings, followed by Culex vishnui and Culex gelidus, while anthropophilic species, such as Culex quiquefasciatus, appear to be more involved in transmission in urban and peri-urban settings. Pigs are the main amplifying hosts and Ardeidae birds are the main wild reservoir. However, a recent experimental study has shown that young chicks and ducklings can develop viremia high enough to allow transmission of the virus to mosquitoes. Although Japanese encephalitis is still considered a rural disease, several studies in Cambodia, Thailand and Vietnam have detected Japanese encephalitis and its vectors in peri-urban areas. Much remains to be learned about the complex epidemiology of Japanese encephalitis. Mosquito eating habits are a key parameter that can help us improve our understanding of this epidemiology. The objective of this work is to analyze the feeding behavior of the main vectors of Japanese encephalitis in rural and peri-urban areas, in Cambodia, using two methodologies: baited traps and PCR analysis of blood samples intended for the mosquito feeding.

The two expected results are

      • The analysis of the dietary habits of the main species of Japanese encephalitis vectors in rural and peri-urban areas of Cambodia and
      • The verification of the hypotheses made on the respective epidemiological role of these mosquito species in the transmission of Japanese encephalitis and the role played by domestic birds in the epidemiological cycle of Japanese encephalitis in Cambodia.

Website: http://www.onehealthsea.org/comacross/

 

The Ecomore 2 project is funded by AFD (French Development Agency), while the Panic project is funded by ANR. The objective of the project, in a development context, is to determine whether integrated vector management in localized areas (here schools) could reduce the incidence of dengue fever on populations in rural and peri-urban areas. In the participating schools, we will destroy larval development sites with the help of the students and their teachers, we will organize scientific activities and use a bacterial insecticide (Bacillus thuringiensis israelensis), as well as an insecticide which will be distributed by mosquitoes themselves (Pyriproxyfen). The main indicator will be the number of cases of dengue fever in villages located around schools. We will thus be able to define whether the methods used in focused vector control are effective and will also be able to decode the main anthropogenic and / or ecological mechanisms responsible for the emergence of infectious diseases. The purpose of the project is to propose an intervention strategy that the Ministry of Health can apply.

 

The LACANET partners initiated a program to strengthen the One-Health capacities in the Kingdom of Cambodia and Lao People’s Democratic Republic.

To achieve these goals, four integrated project activities were designed to:

      • improve field capacity to conduct disease surveillance;
      • improve laboratory capacity to detect priority pathogens;
      • improve communication and collaboration between One-Health sectors and the two countries;
      • and conduct innovative research projects to investigate drivers of zoonotic disease emergence.

The LACANET One-Health Project made significant progress in improving disease surveillance and reporting in Cambodia and Lao PDR. Improved collaborative linkages between the two target countries, and between the human, veterinary and wildlife health sectors, has strengthened the capacities of each country to conduct disease surveillance and outbreak investigation activities.

The project has also contributed to the inclusion of the environmental/wildlife sector into the national One-Health strategies, which has allowed significant progress in the establishment of wildlife disease surveillance networks in Cambodia and Laos. Innovative research projects to investigate the role of land-use change and wildlife trade in zoonotic disease emergence have revealed important information about priority pathogens, vector distributions and the risks to humans, livestock and wildlife. The LACANET Project has led to a sustainable improvement in OneHealth capacities in Cambodia and Laos that will lead to further cross-sectoral, bilateral activities.

Website: http://www.onehealthsea.org/lacanet/

VECTOLAND is an ASEAN-EU Cooperation in Science, Technology and Innovation. The project was founded by the SEA-EU-NET, an international science cooperation network to deepen science and technology cooperation between Europe and Southeast Asia. Its second meeting was organized by the Medical Entomology Platform at Institut Pasteur du Cambodge, Phnom Penh, Cambodia. The main concerns of the presentations and the workshop was the rapid spreading of some invasive species (i.e. Ae. albopictus and Zika Virus), the difficulty of the struggle against malaria in South East India (i.e. insecticide and drug resistance; management of resistance), the communication with authorities and local population.

This meeting was organized in November 2016 with 24 international scientific presentations, regrouping 16 different partners from 7 countries.

Website: http://www.vectoland.com

ZIKAlliance is a 3-year project funded by the Horizon 2020 program, for research and innovation of the European Union. This international consortium brings together 53 partners and aims to create a global alliance of Zika virus control and prevention. The project has three main objectives:

      • To determine the impact of Zika virus infections during pregnancy and short- and medium-term effects on newborns,
      • To trace the natural history of Zika virus infections in the Man and his environment, in the context of the circulation of other arboviruses, and
      • to create a general research capacity in terms of preparation for future epidemic threats.

In this context, our objective is both to

      • train scientists, at the local level, who are able to respond to such a problem and
      • to study the diversity of potential vectors of ZIKV in wild areas (i.e. i.e. in the natural forest). The idea is to check if the ZIKV cycle exists in natural and preserved areas, and to understand how an exchange could occur between natural and anthropized areas.

Website: https://zikalliance.tghn.org

Support to National Authorities

The following summarizes key support to Cambodian National Authorities during 2019 as part of our ongoing programs and projects.

The medical and veterinary entomology unit works with five different ministries: Ministry of Health, Ministry of Education, Youth and Sport, andMinistry of Agriculture, Forestry and Fisheries, Ministry of Environment and Ministry of Cults and Religion

The article describing the resistance to insecticides of Aedes aegypti populations was presented to the Ministry of Health for a change of insecticide used.

In June 2019, the unit organized an information meeting on the preliminary results of the entomological field study for the directors of schoolsinvolved in the ECOMORE 2 project, the four Provincial Directors of the Ministries of Education, of Youth and Sport and the Ministry of Health of the two provinces and for the working group members. Currently, the directors of the 24 selected schools participate actively in the ECOMORE operational phase by facilitating the entomological surveys. This feedback meeting was important, well perceived and very dynamic and participatory.

In July 2019, 11,000 notebooks were distributed and instructions explained to all school children from the 24 schools of the Ecomore 2 project. The Provincial Directors of Ministry of Education, Youth and Sport in Tboung Khmum and Kampong Cham Provinces were enthusiastic and suggested to provide the notebook to all schoolchildren in their provinces. Finally, technicians and officials from the Ministry ofHealth, specifically the CNM, participated to the Thailand International Cooperation Agency (TICA) training (see Teaching and Training section below) organized at IPC.

Teaching & Training

Teaching

In 2019, Mr. Iva Song, a Cambodian second year Royal University of Phnom Penh master’s degree student in the science of biodiversity for conservation, did his internship at the medical and veterinary entomology unit. His work was on the spatial distribution and dynamics of mosquitos at 40 pagodas in Phnom Penh City, Cambodia.

In 2019, Ms. Sylvaine Jego, a French second year master’s student, did her internship at the same unit. Enrolled at the University of Bretagne Sud, France, she is specializing in statistical models as part of her studies in data science. Her specific work is focused on the determination of environmental factors explaining mosquito species’ distribution with satellite data. She was co-supervised by Vincent Herbreteau (IRD).

In 2020, two additional second year master’s degree students from the master’s of science in biodiversity for conservation at RUPP are expected to undertake further training in the unit.

Training

In 2019, Vincent Herbreteau supervised one training on global information systems (GIS) for technicians. The objective was to build thecompetence of the technicians on QGis software in the framework of medical entomology studies.

In 2019, TICA, in the framework of the AFD-funded Ecomore 2 project organized a training on mosquito systematics in Cambodia at IPC inAugust 2019. Technicians and scientists from CNM and Malaria Unit (IPC) also participated.

In December 2019, a unit technician was trained for a week on Maldi Tof in the medical biology laboratory of IPC. In 2020, two taxonomy (TICA, FSPI) and one molecular entomology (FSPI) trainings are planned.

Team

Sebastien BOYER, PhD

Medical entomologist
Heath of unit

Pierre-Olivier MAQUART, PhD

Entomologist
Post doc

CHHUM Moeun, MSc

Medical entomologist, technician

CHHUOY Kalyan, MSc

Medical entomologist, technician

SUOR Kimhuor, MSc
Medical entomologist, technician

Main International Partners

OPEN HOURS