Tracking and Jumping: A Cophylogenetic Analysis of Host Switching in the Lyssaviruses Public

Abstract

Host switching, in which an infection by a pathogen in a novel host results in sustained
transmission, is an infrequent phenomenon yet is responsible for viral zoonoses that have caused
many emerging infectious diseases in humans. RNA viruses of the Lyssavirus genus, including
the Rabies virus, are found in bat host reservoirs, and the frequency and risk factors for host
switching among these associations have not yet been characterized. Since the lyssaviruses
diverged after their hosts speciated, a history of cospeciation can be rejected, and instead this
study distinguishes between host tracking, in which host and pathogen divergences are tied to
each other, and host jumping, which describes switches that are not constrained by host
phylogeny. The study aims to identify host jumps in lyssavirus history and to characterize the
influence of genetic and geographic distance between hosts as determinants of successful host
jumping. Lyssavirus and bat host phylogenies were generated in BEAST v1.5.2, and host jumps
were identified in TreeMap v2.02β. Genetic distances between hosts and overlap of geographic
bat ranges for identified host jumps were then compared to the same distances for random
pairings of hosts. Eight host jumps were identified to explain the current host-virus associations.
Genetic similarity between donor and recipient hosts does not appear to constrain successful host
jumping. Host jumps occurred between both closely related and more distantly related hosts, and
the genetic distances between hosts of identified jumps were not significantly smaller than those
for random pairings of hosts. Conversely, host jumps were more common between hosts with
greater overlapping ranges, and hosts involved in jumps generally shared similar foraging and
roosting habitats. While genetic similarity may also have an impact, these results suggest that
geographic proximity to new hosts and the number and intensity of contacts between bat species
are the driving factors in host jumping events.

Table of Contents

Introduction

Emerging Zoonotic Diseases

Host Switching

Cophylogenetics and Cospeciation

Computational Methods

Lyssaviruses

Bat Hosts

Objectives

Hypotheses

Aim 1: Reconstruction Analysis

Aim 2: Genetic Distance Analysis

Aim 3: Geographic distance Analysis

Methods

Results

Phylogenetic Analysis

Reconstruction Analysis

Genetic Distance Analysis

Geographic Distance Analysis

Discussion

Future Directions

Conclusion

Appendix A

Appendix B

References

About this Honors Thesis

Rights statement

• Permission granted by the author to include this thesis or dissertation in this repository. All rights reserved by the author. Please contact the author for information regarding the reproduction and use of this thesis or dissertation.

School	Emory College
Department	Biology
Degree	BS
Submission	Honors Thesis
Language	English
Research Field	Biology, Bioinformatics Biology, Ecology Biology, General
Mot-clé	genetic distance cophylogeny host switching geographic overlap lyssavirus
Committee Chair / Thesis Advisor	Real, Leslie, Emory University
Committee Members	Waller, Lance, Emory University De Roode, Jacobus, Emory University

Dernière modification

Primary PDF

Thumbnail	Title	Date Uploaded	Actions
	Tracking and Jumping: A Cophylogenetic Analysis of Host Switching in the Lyssaviruses ()	2018-08-28 10:30:55 -0400	Press to Select an action Download

Supplemental Files

Thumbnail	Title	Date Uploaded	Actions