Modeling the potential of wAu-Wolbachia strain invasion in mosquitoes to control Aedes-borne arboviral infections

Abstract

Arboviral infections such as dengue, Zika and chikungunya are fast spreading diseases that pose significant health problems globally. In order to control these infections, an intracellular bacterium called Wolbachia has been introduced into wild-type mosquito populations in the hopes of replacing the vector transmitting agent, Aedes aegypti with one that is incapable of transmission. In this study, we developed a Wolbachia transmission model for the novel wAu strain which possesses several favourable traits (e.g., enhanced viral blockage and maintenance at higher temperature) but not cyctoplasmic incompatibility (CI)—when a Wolbachia-infected male mosquito mates with an uninfected female mosquito, producing no viable offspring. This model describes the competitive dynamics between wAu-Wolbachia-infected and uninfected mosquitoes and the role of imperfect maternal transmission. By analysing the system via computing the basic reproduction number(s) and stability properties, the potential of the wAu strain as a viable strategy to control arboviral infections is established. The results of this work show that enhanced maintenance of Wolbachia infection at higher temperatures can overcome the lack of CI induction to support wAu-Wolbachia infected mosquito invasion. This study will support future arboviral control programs, that rely on the introduction of new Wolbachia variants.

RNA virome diversity and Wolbachia infection in individual Drosophila simulans flies

“…This is consistent with the data provided here and indicates that Wolbachia might be present in a significant proportion of the natural fly population, at least around Perth. Although w Au does not cause cytoplasmic incompatibility, its spread is suggested to confer fitness advantages (increased survival and/or reproduction) to the host, including antiviral protection [ 48, 49 ], that might favour its spread and prevent the bacteria from being eliminated from D. simulans populations [ 30, 50 ]. However, our comparison of Wolbachia -infected and -uninfected D. simulans in western Australia revealed no clear effect of Wolbachia infection on virome composition and viral abundance between Wolbachia infected and uninfected animals.…”

RNA virome diversity and Wolbachia infection in individual Drosophila simulans flies

“…This is consistent with the data provided here and suggests that Wolbachia might be present in a significant proportion of the natural fly population, at least around Perth. Although w Au does not cause cytoplasmic incompatibility, its spread is hypothesized to confer fitness advantages (increased survival and/or reproduction) to the host, including antiviral protection [47,48], that might favour its spread and prevent the bacteria from being eliminated from D. simulans populations [30,49]. However, our comparison of Wolbachia -infected and uninfected D. simulans in western Australia revealed no clear effect of Wolbachia infection on virome composition and viral abundance between Wolbachia infected/uninfected animals.…”

Modelling the ecological dynamics of mosquito populations with multiple co-circulating Wolbachia strains

“…Other schematics showing the two-strain Wolbachia combinations of wAu and wAlbB, and wMel and wAlbB are shown in the Appendices section (Supplementary Figures S3 and S4). Proportion of aquatic stage mosquitoes that mature to adult females 0.5 13,40 -…”

“…Some Wolbachia features regulating the success of these mechanisms include immune system preactivation in the vectors, induction of cytoplasmic incompatibility (CI) rendering offspring unviable, imperfect maternal transmission of Wolbachia, loss of Wolbachia infection (LWI) due to high temperature, and superinfection by a second Wolbachia strain [9][10][11][12] . Based on these features, there are some tradeoffs exhibited by different Wolbachia strains, i.e., some strains induce CI (which is good) but also have LWI due to high temperature (which is bad) and vice versa 13,14 .…”