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

• Published in: PLoS neglected tropical diseases 2021-09, Vol.15 (9), p.e0009752
• Main Authors: Pocquet, Nicolas, O'Connor, Olivia, Flores, Heather A, Tutagata, Jordan, Pol, Morgane, Hooker, David J, Inizan, Catherine, Russet, Sylvie, Duyvestyn, Johanna M, Pacidônio, Etiene C, Girault, Dominique, da Silva Gonçalves, Daniela, Minier, Marine, Touzain, Frédéric, Chalus, Elodie, Lucien, Kevin, Cheilan, Florie, Derycke, Tristan, Laumond, Sylvie, Simmons, Cameron P, Dupont-Rouzeyrol, Myrielle, Rossi, Nadège
• Format: Article
• Language: English
• Subjects: Aedes - microbiology; Animals; Biology and Life Sciences; Chikungunya virus - physiology; Dengue Virus - classification; Dengue Virus - physiology; Disease transmission; Insects as carriers of disease; Life Sciences; Medicine and Health Sciences; Mosquito Control - methods; Mosquito Vectors - microbiology; New Caledonia; Pest Control, Biological - methods; Physiological aspects; Rickettsiales infections; Risk factors; Vector-borne diseases; Wolbachia; Zika Virus - classification
• ISSN: 1935-2735; 1935-2727; 1935-2735
• DOI: 10.1371/journal.pntd.0009752

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. 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. 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.