Date of Award

January 2026

Document Type

Open Access Thesis

Degree Name

Master of Public Health (MPH)

Department

School of Public Health

First Advisor

Albert I. Ko

Second Advisor

Julio Croda

Abstract

Chikungunya is a mosquito-borne arboviral disease primarily transmitted by Aedes aegypti and Aedes albopictus that is rapidly emerging in new geographical settings because of climate change, viral adaptation, and globalization. Brazil has experienced the significant expansion of chikungunya over the past decade and has adopted novel vector control interventions, including Wolbachia-based population replacement, as part of its public health response. While the effectiveness of wMel Wolbachia on dengue incidence has been demonstrated across multiple settings, evidence on its effect on chikungunya risk remains limited. Large-scale releases of wMel-infected Aedes aegypti mosquitoes were implemented in the city of Campo Grande, Brazil between December 2020 and December 2023. This study evaluated the effectiveness of this intervention on chikungunya incidence using interrupted time series (ITS) analysis and augmented synthetic control methods (ASCM), drawing on monthly municipality-level surveillance data from January 2017 to December 2025. Neither the ITS nor the ASCM identified a statistically significant reduction in chikungunya incidence in Campo Grande following the intervention. The absence of a significant effect is likely attributable to the inherent limitations of observational studies that seek to evaluate an intervention to an emerging infectious disease with a single concentrated post-intervention outbreak, limited pre-intervention baseline data, and no comparable control.

Comments

This is an Open Access Thesis.

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