BIOPHYSICAL MODELS OF WEST NILE VIRUS TRANSMISSION IN CULEX PIPIENS

Graduation Date

Spring 5-9-2026

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Programs

Medical Sciences Interdepartmental Area

First Advisor

Dr Jesse E Bell

Abstract

West Nile virus (WNV) transmission is governed by complex interactions between environmental exposure, vector biology, and other factors. Despite countless methods to model disease outcomes using environmental information, few such models can outperform simple negative binomial models in forecasting challenges. This dissertation progresses through successively complex building blocks to explore correlative and mechanistic modeling approaches to predict application-relevant WNV outcomes, focusing on the primary vector Culex pipiens, to explore opportunities to improve prediction skill.

Chapter 1 presents a meta-analysis of the effect of temperature on WNV disease cases. By synthesizing existing correlative studies, this chapter evaluates the extent to which observation biases, such as the use of unconfirmed versus confirmed neuroinvasive disease (WNND) cases, and other methodological decisions drive heterogeneity in the literature. It establishes a baseline for how temperature influences human cases of WNV.

Chapter 2 investigates WNV transmission suitability by modeling the influence of the environment on biophysical traits of Cx. pipiens mosquitos. Customizing a pre-existing R package, to model the steps in the sylvatic cycle, this chapter introduces several new improvements to the model including replacing Relative Humidity with Vapor Pressure Deficit to better represent evaporative stress on mosquitos. The analysis highlights the importance of matching mechanistic models with the species driving transmission, suggesting that an ensemble of species-specific trait models may be useful rather than a generalized model.

Chapter 3 addresses a key gap in mosquito biology by examining the environmental mechanisms of diapause in Cx. pipiens. Because diapause temporarily removes mosquitoes from the transmission cycle, understanding its timing is critical. This chapter identifies the critical photoperiods and interacting environmental cues that regulate diapause, defining an observed lag of ~47.5 days between the critical photoperiod and population growth rate surges.

Collectively, this research demonstrates the necessity of carefully considering the limitations of each modeling approach to select the best approach for the intended application of the predictions. By detailing temperature-driven disease patterns, customized thermal traits, and diapause phenology, this dissertation provides the foundational framework needed to improve the accuracy of mechanistic models and better predict the spatiotemporal risk of WNV outbreaks.

Rights

The author holds the copyright to this work and any reuse or permissions must be obtained from the author directly.

Available for download on Saturday, April 29, 2028

Share

COinS