Vector competence of Aedes aegypti from New Caledonia for the four recent circulating dengue virus serotypes.

Nicolas Pocquet,Elodie Calvez,Vincent Richard,Catherine Inizan,Olivia O’Connor,Duane J Gubler,Myrielle Dupont-Rouzeyrol

doi:10.1371/journal.pntd.0008303

Nicolas Pocquet, Elodie Calvez + Show 5 more

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https://doi.org/10.1371/journal.pntd.0008303

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Abstract

In New Caledonia (NC), Aedes aegypti is the only proven vector of dengue virus (DENV), which is the most prevalent arbovirosis in NC. Since World War II, the four DENV serotypes have circulated regularly in NC. The epidemiological profile, however, has evolved over the last ten years, with the persistence of DENV-1 circulation and the co-circulation of several DENV serotypes. The current study evaluated the ability of Ae. aegypti from NC to transmit four DENV serotypes (and two DENV-1 genotypes) isolated during recent outbreaks in NC. An Ae. aegypti F1 generation was twice independently orally challenged with each DENV strain (107 FFU/ml). Infection, dissemination and transmission rates and transmission efficiency were measured at day 7 and 14 post-exposure, as well as the quantity of infectious virus particles. Mosquito infection was observed as early as 7 days post-infection. Infection rates between 18 and 58% were measured for all DENV serotypes/genotypes tested. Although dissemination rates ranged from 78 to 100%, transmission efficiencies were low, with values not exceeding 21% at 14 days post-infection for all DENV strains. This study shows that NC Ae. aegypti are moderately competent for DENV in laboratory conditions. In link with epidemiological data, these results suggest implication of other factors in the sustained circulation of DENV-1 in New Caledonia.

Highlights

Dengue fever is a worldwide public health concern, with approximately 390 million persons affected each year and 4 billion considered at risk [1]
Our results demonstrate that this vector is moderately competent for Dengue virus (DENV), with slight differences observed between DENV serotype/genotype in terms of transmission
Infection rates at 7 dpi ranged from 18% to 40% for the four DENV serotypes, with no significant difference (Fig 1A; S1 Table)

Summary

Introduction

Dengue fever is a worldwide public health concern, with approximately 390 million persons affected each year and 4 billion considered at risk [1]. A broad spectrum of clinical manifestations can be encountered, usually ranging from unapparent infections to mild-febrile illness. Severe forms of dengue, can occur with hemorrhagic manifestations, sometimes with a fatal outcome [2]. Dengue virus (DENV) is a positive-sense single-stranded RNA virus belonging to the Flaviviridae family. Four serotypes (DENV-1 to -4) can be antigenically distinguished. Infection by one serotype does not confer prolonged immunity against the others [4]. Like many RNA viruses, dengue viruses exhibit an extensive genetic diversity which makes it possible to identify distinct genotypes within each serotype [5]. DENV are transmitted to humans by the bite of infected Aedes mosquitoes, such as Aedes aegypti which is the most common vector, or, to a lesser extent, Aedes albopictus [6]

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