# Linking host energetics and multiple host defenses to transmission and virulence evolution

> **NIH NIH F32** · UNIVERSITY OF NEBRASKA LINCOLN · 2020 · $5,776

## Abstract

PROJECT SUMMARY
 The evolution of pathogen traits such as virulence and transmission poses an increasingly
formidable challenge to basic and applied biology. Virulence and transmission fundamentally
shape the severity and spread of disease and the evolution of these traits frequently
undermines strategies to mitigate disease (e.g., vaccines, drugs, diet). Predicting virulence
evolution remains challenging, in large part, because one of the most important drivers of
pathogen evolution, host defense, remains poorly understood. Multiple host defense
mechanisms strongly determine pathogen production (within hosts) and thus transmission
between hosts at the population-level. Hence, both within-host and between-host processes
ultimately govern pathogen evolution. Yet, host defense mechanisms and their effects on
transmission are also difficult to unravel. Host defenses are energetically costly, interfere with
one another and with other aspects of host physiology (e.g., growth, reproduction), vary across
host genotypes, and are sensitive to environmental conditions (e.g., resource availability). Better
understanding of within-host processes and their effects on transmission will substantially
improve our ability to link these different scales of biological organization to pathogen evolution.
Recent theory suggests that such cross-scale links can provide key insight into pathogen
evolution. To date, however, this theory has not been tested empirically.
 We propose to identify how fundamental interactions between host energetics and multiple
host defense mechanisms shape the evolution of virulence and transmission. This project
integrates (i) the development of novel energetic and evolutionary theory with (ii) individual and
population-level experiments using a model host-pathogen system, Daphnia magna and
Pasteuria ramosa (to leverage this system’s well-known genetic and environmental variation in
host defense and rigorously test theoretical predictions). This integration will determine (1) the
unique and composite effects of different host defense mechanisms on pathogen production; (2)
how environmental variation in resource availability affects host defense strategies, pathogen
production, virulence, and transmission; and (3) whether understanding mechanistic
connections within and between hosts improves our ability to accurately predict pathogen
evolution across different environmental and genetic backgrounds. We will develop
mathematical models that explicitly integrate resources (host diet) and within-host and between-
host dynamics to predict epidemiological and evolutionary dynamics (virulence and transmission
evolution).

## Key facts

- **NIH application ID:** 10222441
- **Project number:** 3F32GM128246-02S1
- **Recipient organization:** UNIVERSITY OF NEBRASKA LINCOLN
- **Principal Investigator:** Jessica Leigh Hite
- **Activity code:** F32 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $5,776
- **Award type:** 3
- **Project period:** 2018-09-01 → 2020-09-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10222441

## Citation

> US National Institutes of Health, RePORTER application 10222441, Linking host energetics and multiple host defenses to transmission and virulence evolution (3F32GM128246-02S1). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10222441. Licensed CC0.

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