Combining Wolbachia-induced sterility and virus protection to fight Aedes albopictus-borne viruses

Riccardo Moretti (1) , Pei-Shi Yen (2) , Vincent Houé (2) , Elena Lampazzi (1) , Angiola Desiderio (1) , Anna-Bella Failloux (2) , Maurizio Calvitti (3)

1 ENEA - Agenzia Nazionale per le nuove Tecnologie, l’energia e lo sviluppo economico sostenibile = Italian National Agency for New Technologies, Energy and Sustainable Economic Development
2 Arbovirus et Insectes Vecteurs - Arboviruses and Insect Vectors
3 ENEA - Italian National agency for new technologies, Energy and sustainable economic development [Frascati]

Among the strategies targeting vector control, the exploitation of the endosymbiont Wolba-chia to produce sterile males and/or invasive females with reduced vector competence seems to be promising. A new Aedes albopictus transinfection (ARwP-M) was generated by introducing wMel Wolbachia in the ARwP line which had been established previously by replacing wAlbA and wAlbB Wolbachia with the wPip strain. Various infection and fitness parameters were studied by comparing ARwP-M, ARwP and wild-type (S ANG population) Ae. albopictus sharing the same genetic background. Moreover, the vector competence of ARwP-M related to chikungunya, dengue and zika viruses was evaluated in comparison with ARwP. ARwP-M showed a 100% rate of maternal inheritance of wMel and wPip Wolba-chia. Survival, female fecundity and egg fertility did not show to differ between the three Ae. albopictus lines. Crosses between ARwP-M males and S ANG females were fully unfertile regardless of male age while egg hatch in reverse crosses increased from 0 to about 17% with S ANG males aging from 3 to 17 days. When competing with S ANG males for S ANG females, ARwP-M males induced a level of sterility significantly higher than that expected for an equal mating competitiveness (mean Fried index of 1.71 instead of 1). The overall Wolbachia density in ARwP-M females was about 15 fold higher than in ARwP, mostly due to the wMel infection. This feature corresponded to a strongly reduced vector competence for chikungunya and dengue viruses (in both cases, 5 and 0% rates of transmission at 14 and 21 days post infection) with respect to ARwP females. Results regarding Zika virus did not highlight significant differences between ARwP-M and ARwP. However, none of the tested ARwP-M females was capable at transmitting ZIKV. These findings are expected to promote the exploitation of Wolbachia to suppress the wild-type Ae. albopictus populations. PLOS Neglected Tropical Diseases | https://doi.

Mots clés: Mosquitoes; Chikungunya infection; Dengue virus; Saliva; Zika virus; Vector biology; Wolbachia; Chikungunya virus

Domaines: Virologie

Riccardo Moretti, Pei-Shi Yen, Vincent Houé, Elena Lampazzi, Angiola Desiderio, et al.. Combining Wolbachia-induced sterility and virus protection to fight Aedes albopictus-borne viruses. PLoS Neglected Tropical Diseases, 2018, 12 (7), pp.e0006626. ⟨10.1371/journal.pntd.0006626⟩. ⟨pasteur-01857926⟩