Assessment of fitness and vector competence of a New Caledonia wMel Aedes aegypti strain before field-release

Nicolas Pocquet (1) , Olivia O'Connor (2) , Heather A. Flores (3) , Jordan Tutagata (1) , Morgane Pol (1) , David J. Hooker (3) , Catherine Inizan (2) , Sylvie Russet (4) , Johanna M. Duyvestyn (3) , Etiene C. Pacidônio (3) , Dominique Girault (2) , Daniela da Silva Gonçalves (3) , Marine Minier (2) , Frédéric Touzain (5) , Elodie Chalus (5) , Kevin Lucien (6) , Florie Cheilan (7) , Tristan Derycke (6) , Sylvie Laumond (7) , Cameron P. Simmons (3, 8, 9) , Myrielle Dupont-Rouzeyrol (2) , Nadège Rossi (4)

1 URE-EM - Entomologie médicale [Nouméa, Nouvelle-Calédonie]
2 URE-DA - Dengue et Arbovirose
3 Monash University [Melbourne]
4 Institut Pasteur de Nouvelle-Calédonie
5 Centre hospitalier territorial Gaston-Bourret [Nouméa]
6 Mairie de Nouméa [Nouvelle-Calédonie]
7 DASS [Nouméa] - Direction des Affaires sanitaires et sociales de la Nouvelle-Calédonie [Nouméa]
8 OUCRU - Oxford University Clinical Research Unit [Ho Chi Minh City]
9 University of Oxford

Background Biological control programs involving Wolbachia-infected Aedes aegypti are currently deployed in different epidemiological settings. New Caledonia (NC) is an ideal location for the implementation and evaluation of such a strategy as the only proven vector for dengue virus (DENV) is Ae. aegypti and dengue outbreaks frequency and severity are increasing. We report the generation of a NC Wolbachia-infected Ae. aegypti strain and the results of experiments to assess the vector competence and fitness of this strain for future implementation as a disease control strategy in Noumea, NC. Methods/principal findings The NC Wolbachia strain (NC-wMel) was obtained by backcrossing Australian AUS-wMel females with New Caledonian Wild-Type (NC-WT) males. Blocking of DENV, chikungunya (CHIKV), and Zika (ZIKV) viruses were evaluated via mosquito oral feeding experiments and intrathoracic DENV challenge. Significant reduction in infection rates were observed for NC-wMel Ae. aegypti compared to WT Ae. aegypti. No transmission was observed for NC-wMel Ae. aegypti. Maternal transmission, cytoplasmic incompatibility, fertility, fecundity, wing length, and insecticide resistance were also assessed in laboratory experiments. Ae. aegypti NC-wMel showed complete cytoplasmic incompatibility and a strong maternal transmission. Ae. aegypti NC-wMel fitness seemed to be reduced compared to NC-WT Ae. aegypti and AUS-wMel Ae. aegypti regarding fertility and fecundity. However further experiments are required to assess it accurately. Conclusions/significance Our results demonstrated that the NC-wMel Ae. aegypti strain is a strong inhibitor of DENV, CHIKV, and ZIKV infection and prevents transmission of infectious viral particles in mosquito saliva. Furthermore, our NC-wMel Ae. aegypti strain induces reproductive cytoplasmic incompatibility with minimal apparent fitness costs and high maternal transmission, supporting field-releases in Noumea, NC.

Domains: Life Sciences [q-bio]

Nicolas Pocquet, Olivia O'Connor, Heather A. Flores, Jordan Tutagata, Morgane Pol, et al.. Assessment of fitness and vector competence of a New Caledonia wMel Aedes aegypti strain before field-release. PLoS Neglected Tropical Diseases, 2021, 15 (9), pp.e0009752. ⟨10.1371/journal.pntd.0009752⟩. ⟨pasteur-03364844⟩