# Arbovirus population biology: temperature impacts on selection and collective dynamics

> **NIH NIH R01** · COLORADO STATE UNIVERSITY · 2023 · $348,383

## Abstract

Arthropod-borne viruses (arboviruses) adapt to local conditions, maximizing their potential to perpetuate and
emerge as health threats. The adaptive potential of arboviruses is driven by error-prone replication, which
creates a genetically diverse pool of competing virus genotypes within each host. One of the most important
ways that the environment is changing is that temperatures are rising. This proposal examines some of the
ways that temperature may impact arbovirus evolutionary biology.
Aim 1 will address how a comprehensive temperature gradient that includes both constant and fluctuating
temperatures with varying means and amplitudes alters natural selection on WNV populations within
mosquitoes and the strength of bottlenecks. Our predictions are that fluctuating temperatures will increase the
strength of purifying selection, that diversity will be maximized at optimal constant temperatures, and that
bottlenecks will become wider as temperature increases. Flaviviruses infections are most frequently initiated by
aggregates of virus particles. Aim 2 will address the extent that this occurs in a host- and temperature-
dependent manner, bringing our previous work into a more ecologically relevant, realistic context. In the
second phase of Aim 2, we will ask whether these genome aggregates can help to facilitate the maintenance
of genetic diversity in the WNV population. This is important because population bottlenecks can significantly
impact virus fitness, and aggregation of genomes in individual infections may help viruses escape from them.
We have found that birds that generate high WNV viremia and are highly infectious to mosquitoes (crows)
have significantly more unique WNV genomes per cell than those that have lower viremias (robins). Aim 3 will
assess whether this also may occur in mosquitoes. We also will assess the degree to which this phenomenon
may allow for the maintenance of low fitness viral genotypes while preventing those of high fitness from gaining
dominance. Preliminary data supporting the feasibility of these studies is provided in the application.
The significance of this work is that it will provide novel, comprehensive data on the ways that changing
environmental conditions such as those that we are now experiencing may alter the fundamental population
biology of arboviruses. Arboviruses are uniquely susceptible to these conditions because they must replicate in
mosquitoes. This is inherently significant. Our work is also significant because it will provide mechanistic data
on how viruses may maintain genetic diversity in the face of both selective and stochastic reductions in genetic
diversity. Finally, the significance of our work is that we have provided technical and analytical tools that are
broadly useful and have permitted us to collaborate effectively with a wide array of investigators. The proposed
studies are technically and conceptually innovative because of the ways that we can combine realistic
transmission s...

## Key facts

- **NIH application ID:** 10568405
- **Project number:** 1R01AI173206-01
- **Recipient organization:** COLORADO STATE UNIVERSITY
- **Principal Investigator:** Gregory David Ebel
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $348,383
- **Award type:** 1
- **Project period:** 2023-09-01 → 2027-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10568405

## Citation

> US National Institutes of Health, RePORTER application 10568405, Arbovirus population biology: temperature impacts on selection and collective dynamics (1R01AI173206-01). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/10568405. Licensed CC0.

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