Dengue severity

2017 Dengue outbreak, Investigations of severe cases : Dengue Severity
Principal investigator M. Dupont-Rouzeyrol
IPNC main investigator M. Dupont-Rouzeyrol
IPNC collaborators A. Tarantola, C. Inizan, M. Minier, O. O’Connor
Other collaborators E. Simon-Lorière, A. Sakuntabhai (IPP), E. Descloux, M. Sérié, M.-A. Goujart,, A.-C. Gourinat (CHT), C. Forfait, A. Pfannstiel (DASS-NC).
Budget Budget devoted to IPNC 
Financial supports IPNC, IPP, CHT, NC
Timeline Start date: Sept.2017 End date : Sept. 2018
With 4,401 dengue cases (2,548 biologically confirmed), 579 hospitalized cases and 11 deaths between Jan 1st and Oct 8th 2017, the 2016-2017 dengue epidemic in New Caledonia (NC) was sizeable. More importantly, it was associated with a higher percentage of hospital admissions and severe clinical presentations (liver injury, ophthalmic complications…). The higher occurrence of deaths and heretofore rare hepatic forms observed during this epidemic may be linked with specific characteristics of viruses, patients, or host-pathogen response.
To determine whether severe presentations of dengue infections were associated with specific characteristics such as virus genotype and hepatic tropism, patient comorbidities or earlier infection by dengue or Zika viruses.
Patients already included in the ArboVirtuess study will be asked to continue their participation and contribute an additional blood sample.

– Selection of 50 sera from 2017 and previous years available for analysis: 1/3 severe forms versus 2/3 non-severe

– Phylodynamic studies based on whole-genome sequencing. Search for variations in viral quasi-species.

– Comparative analysis of the hepatic tropism of viral strains representative of 2016-2017 epidemic versus previous years

– Sera characterization: history of previous arbovirus infections, impact of pre-existing humoral immunity on DENV replication in human monocytes (ADE)

Preliminary results
Ethical approval for patient recall have been obtained and sera have been selected and collected. Viral RNAs have been extracted from the sera and whole-genome sequencing is in progress. In parallel, viruses from this year’s epidemic are currently being isolated on mosquito C6/36 cells and will be titrated. Experimental conditions for human hepatic cell line infection as well as for ADE have been set up and are currently being validated. Characterization of viruses’ hepatic tropism and sera inhibition/enhancement capacity will soon be initiated.
First, this study may shed light on a potential evolution of viruses involved in severe cases compared to non-severe dengue cases, in link with a modification in virus hepatic tropism. Second, this project will provide an unprecedented characterization of the impact of anti-Zika antibodies on DENV infection. Overall, this study is expected to further the understanding of the unusual severity of DENV epidemic in 2017. Such documentation of the influence of a pre-existing anti-Zika humoral immunity on dengue severity would be useful for territories displaying an epidemiological situation similar to NC, thus suggesting a new indicator to estimate the risk of progression towards severe dengue.


Acronym: VECPAE Arbovirus vectors in the Pacific: diversity, distribution and identification tools of Aedes sp. for public health.
Principal investigator Nicolas POCQUET
Focal point IPNC Nicolas POCQUET
Collaborators at IPNC Morgane POL, Sosiasi KILAMA, Myrielle DUPONT-ROUZEYROL.
Other collaborators Hervé BOSSIN (ILM), Van-Mai CAO-LORMEAU (ILM), Mike KAMA (MoH Fiji), Esau NAKET (MoH Vanuatu), Matthew SHORTUS (WHO)
Budget  60 000€ Budget devoted to IPNC: 60 000€
Funding Pacific Fund (30 000€), IPNC (30 000€)
Timeline Start date: Oct. 2017 End date: March 2019
Vector-borne diseases are a major public health concern in the Pacific. In addition to dengue, the last five years have seen the emergence of chikungunya and Zika viruses in the South Pacific. These viruses are transmitted by mosquitoes of the Aedes genus (subgenus Stegomyia), whose a large number of species are present in the Pacific. Identifying these species in the different Pacific Island Countries and Territories (PICT) is an essential prerequisite to assess the risk for the population and develop an adapted control strategy. Unfortunately, most of these species belong to the scutellaris group and are morphologically very close. Their identifications require important expertise that is not always available on site.
This project meets this needs by i) strengthening the capacity of Aedes vectors identification in the partner territories (Vanuatu and Fiji), ii) updating the knowledge on the distribution of arbovirus vectors in Vanuatu, Fiji, French Polynesia and New Caledonia, and iii) developing a tool for the rapid identification of vector mosquitoes for all PICT, based on the use of modern identification tools (Molecular Biology and Maldi-Tof Mass Spectrometry).
Task 1: Transfer of skills. Two training missions in entomology will be conducted in Fiji and Vanuatu.

Task 2: Vector distribution. During these missions in Fiji and Vanuatu, an inventory of the Aedes species of the scutellaris group will be carried out. The same type of inventory will be carried out in New Caledonia and French Polynesia respectively by IPNC and ILM. The mosquitoes collected will be identified and kept for the rest of the project.

Task 3: Development of an identification tool. This part of the project aims to develop a fast and reliable tool for identifying Aedes species from the scutellaris group. For that, the sequencing of a gene allowing the species differentiation will be realized for individuals of each species and each locality, captured during the field missions. Thanks to the sequences obtained, an end-point real-time PCR will be developed, in order to have a faster and less expensive identification tool than sequencing.

Finally, a rapid identification tool will be developed through Maldi-Tof mass spectrometry. This tool allows obtaining a specific protein spectrum of a species in a very short time and for a relatively low cost.

Expected Results
At the end of the project, we will have a database combining, for several individuals of each species found, i) morphological description, ii) sequence of gene of interest and iii) protein profile generated in mass spectrometry.
This partnership including for the moment Fiji, Vanuatu, French Polynesia and New Caledonia, can be extended afterwards to other PICT, which will help to anticipate the health risk for the region.


Acronym: VIP Are dengue Defective Interfering Particles truly interfering?
Principal investigator C. Inizan
IPNC focal point C. Inizan / M. Dupont-Rouzeyrol
IPNC collaborators O. O’Connor
Other collaborators
Project total budget 8 275 € Budget devoted to IPNC  NA
Financial support IPNC
Timeline Start: March 2017 End: Feb. 2018
Polymerase errors occurring upon viral replication might give rise to incomplete genomes that are nevertheless encapsidated in Defective Viral Particles (DVP). Replicated and maintained upon co-infection with functional viruses, such DVPs might affect the physiopathology of the infection: inhibition of viral replication, modulation of the host immune response as well as contribution to infection persistence. In the case of dengue virus (DENV), DVPs have been detected in both humans and Aedes mosquitoes. They might represent a natural regulator of viremia in patients, thus impacting infection evolution and resolution.
The current study aims at evaluating DVP role in viremia regulation in patients. This project includes (i) the characterization and quantification of DVPs in the sera of dengue patients, in link with viremia and, (ii) the measure of DVP impact on DENV replication in vitro.
Molecular characterization of DVPs in the sera of dengue patients from New Caledonia:

– Evaluation of patients viremia through in vitro infections and real-time RT-PCT

– Quantification and analysis of DVPs subgenomic RNA profiles in patients’ sera through real-time RT-PCR

– Sequencing of DVPd subgenomic RNAs in patients sera

Measure of the modulation of DENV replication in vitro by DVPs:

– Production and purification of DVPs through in vitro infections and ultracentrifugation

– Quantification of DVP impact on DENV replication in human cells in vitro through real-time RT-PCR

Preliminary results
Viral infectious titers of 50 sera of patients from New Caledonia infected by DENV-1 genotype I have been evaluated through in vitro infections. In parallel, viral RNAs have been extracted from those sera. Molecular analyses are being set up and will soon enable the quantification and sequencing of DVPs subgenomic RNAs.
Through the implementation of DVPs detection and purification tools, the current project opens new avenues for a broader study on DVPs role in DENV natural cycle, aiming at measuring their impact on dengue physiopathology and transmission. This study of the impact of DVPs on viremia might suggest their quantification in patients’ sera as a prognostic tool for infection severity.


Acronym : R-Zero Risk factors for Zika virus Emergence and Recurrent Outbreaks within the Pacific area.
Principal investigator VM. Cao-Lormeau (ILM)
IPNC main investigator M. Dupont-Rouzeyrol
IPNC collaborators D. Girault, A. Tarantola
Other collaborators Ministère de la santé de Fidji, Samoa et Yap, Institut Pasteur, London School of Hygiene and Tropical Medicine, Queensland University of Technology
Project total budget 32 000€
(phase 1)
Budget devoted to l’IPNC  3 000 €
Financial supports Pacific Funds (phase 1/3)
Timeline Start date: Jul 2017 End date: July 2018
In 2014, Zika (ZIKV) emerged in the Pacific region and spread in the world. In early 2016, WHO declared the ZIKV outbreak an international public health emergency in connection with the severe neurological consequences observed following ZIKV infection. Since then, the number of countries reporting a Zika epidemic has steadily increased, illustrating that ZIKV’s geographic expansion is still ongoing, even in the region. In addition, the reappearance of ZIKV in the Federated States of Micronesia, Kosrea, 8 years after the Yap epidemic, illustrates the risk of outbreak’s recurrence in previously exposed areas.
The overall objective of this project is to identify the risk factors for the emergence and recurrence of Zika epidemics in the Pacific, with a particular focus on anti-Zika community immunity.
Characterization of the memory immune response against ZIKV – persistence and possible interference with dengue

Community mmunity against ZIKV – Status and Evolution in 4 Pacific sites

Epidemic dynamics of Zika – risk factors for epidemic emergence and recurrence

This project is expected to gather crucial information on the persistence of protective immunity against Zika virus in infected patients. It should also be used to assess the level of exposure and immunity of Pacific populations to the Zika virus.
Communication : M. Dupont-Rouzeyrol, R-Zero Workshop, Tahiti, 2017 (Oral)


Acronym : ZikAlliance A global Alliance for Zika Virus control and prevention.

Principal investigator X. de Lamballerie (Inserm)
IPNC main investigator M. Dupont-Rouzeyrol
IPNC collaborators N. Pocquet, O. O’Connor, M. Minier
Other collaborators AB. Failloux (IP), ZikAlliance consortium, task 6.2
Project total budget 11.9M€ Budget devoted to IPNC: 30 000 €
Financial supports H2020
Timeline Start date: Jan. 2017 End date: December 2019
In 2014, Zika (ZIKV) emerged in the Pacific region and spread in the world. In early 2016, WHO declared the ZIKV outbreak an international public health emergency in connection with the severe neurological consequences observed following ZIKV infection. The ZikAlliance project is a large project that aims to study ZIKV and its consequences at different scales and across different environments. IPNC is a partner of this project and is involved in the WP6: Vectors and Vector control and more particularly the vector competence part. The objectives presented here correspond only to the task in which IPNC is a partner.
Evaluate the vector competence of several mosquitoes species and populations from different environments (American Asia, Africa…) against several ZIKV lineage
Homogenization of protocols.

Generation of F1 populations of Aedes aegypti and Culex quinquefasciatus from New Caledonia.

Production of Zika virus stocks, different lineages.

Vector competence experiments: measurement of infection, dissemination and transmission parameters.

Analysis of the results at the global scale.


Two populations of Ae. aegypti (Nouméa and Koné) were generated. The ZIKV African lineage and Asian / American lineage were received. Experimental infections are scheduled for the first half of 2018.
Mieux connaître la capacité de transmission des différents vecteurs pour les différentes lignées est nécessaire à l’évaluation du risque et à la mise en place de méthodes de lutte et de prévention plus ciblées et plus performantes.
Publications : Dupont-Rouzeyrol et al, In press, Calvez et al, submitted ; Boyer et al, submitted; Simon et al, submitted ; Calvez et al, in prep.



Research Infrastructure Program on insect vectors of human and animal disease


Principal investigator Institut Pasteur
Focal point IPNC Nicolas Pocquet,
Collaborators at IPNC Myrielle Dupont-Rouzeyrol, Olivia O’Connor, Morgane Pol, Sosiasi Kilama
Other Collaborators 24 consortium partners (IP, UG, POLOGGB, IRD, IPNC, CUNI, CIRAD, Imperial, IRTA, EMBL, TPI, CAA, Trop IQ, MPIIB, FORTH, RUMC, UNS-FA, UZH, LSTM, IPD, USTTB, HSeT, WU, CNRFP).
Total budget of project 10 000 000 € Budget devoted to IPNC: 78 860 €
Funding European Commission Horizon 2020
Timeline Start date: March 2017 End date: 2020
Insect vectors transmit parasitic diseases such as malaria and leishmaniasis, and viral infections such as chikungunya, dengue, Zika, Japanese encephalitis and yellow fever. The 24 consortium partners hold the major European biosecure insectaries for experimental infection and containment of insect vectors under Containment Level 2 and 3 (CL2/CL3) conditions, other key insect vector facilities, and include front-line field sites in Africa, the Pacific, and the Americas.
The Infravec2 project provides research resources and access to key infrastructures for insect vector biology at no cost to the end-user. The goal is to accelerate European research in insect vector biology research, and to develop new vector control measures targeting the greatest threats to human health and animal industries.

As part of this project, IPNC will provide access to its Level 2+ laboratory for experimental infection with Aedes aegypti, and to provide dead mosquitoes (Ae. aegypti or Culex quinquefasciatus) or eggs of Ae. aegypti.

IPNC is also in charge of creating a reference strain of Ae. aegypti whose microbiota will be characterized at the beginning of the breeding and during the generations.


Infravec2 will improve the exploitation of European vector infrastructures for research and public health, and will develop other innovative methodologies and technologies.