Establishment of
wMel
Wolbachia in
Aedes aegypti mosquitoes and reduction of local dengue transmission in Cairns and surrounding locations in northern Queensland, Australia.
Gates Open Res 2020;
3:1547. [PMID:
31667465 PMCID:
PMC6801363 DOI:
10.12688/gatesopenres.13061.2]
[Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/01/2020] [Indexed: 01/14/2023] Open
Abstract
Background: The
wMel strain of
Wolbachia has been successfully introduced into
Aedes aegypti mosquitoes and subsequently shown in laboratory studies to reduce transmission of a range of viruses including dengue, Zika, chikungunya, yellow fever, and Mayaro viruses that cause human disease. Here we report the entomological and epidemiological outcomes of staged deployment of
Wolbachia across nearly all significant dengue transmission risk areas in Australia.
Methods: The
wMel strain of
Wolbachia was backcrossed into the local
Aedes aegypti genotype (Cairns and Townsville backgrounds) and mosquitoes were released in the field by staff or via community assisted methods. Mosquito monitoring was undertaken and mosquitoes were screened for the presence of
Wolbachia. Dengue case notifications were used to track dengue incidence in each location before and after releases.
Results: Empirical analyses of the
Wolbachia mosquito releases, including data on the density, frequency and duration of
Wolbachia mosquito releases, indicate that
Wolbachia can be readily established in local mosquito populations, using a variety of deployment options and over short release durations (mean release period 11 weeks, range 2-22 weeks). Importantly,
Wolbachia frequencies have remained stable in mosquito populations since releases for up to 8 years. Analysis of dengue case notifications data demonstrates near-elimination of local dengue transmission for the past five years in locations where
Wolbachia has been established. The regression model estimate of
Wolbachia intervention effect from interrupted time series analyses of case notifications data prior to and after releases, indicated a 96% reduction in dengue incidence in
Wolbachia treated populations (95% confidence interval: 84 – 99%).
Conclusion: Deployment of the
wMel strain of
Wolbachia into local
Ae. aegypti populations across the Australian regional cities of Cairns and most smaller regional communities with a past history of dengue has resulted in the reduction of local dengue transmission across all deployment areas.
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