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AEROMONAS HYDROPHILA IN AMPHIBIANS: HARMLESS BYSTANDER OR OPPORTUNISTIC PATHOGEN

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Date Issued:
2016
Abstract/Description:
For several decades amphibian populations have been declining. Historically, the bacterium A. hydrophila (Ah) was hypothesized to be the causal factor in amphibian disease and population declines. However, with the discovery of a chytrid fungus, Batrachochytrium dendrobatidis (Bd) in 1998, which was identified on the skin of amphibians during documented mortality events, Ah research became of minor interest as focus shifted to Bd. Recent studies into the immunocompromising abilities of Bd, however, have opened new questions about its relationship with Ah and their combined effects on a host. In this study, I explore the relationship between infection with these two pathogens, Bd and Ah, in two amphibian species from distinct regions of the United States. I developed a novel qPCR assay to measure the microbial load of Ah on the skin of two anuran species, Lithobates yavapaiensis (N=232) and Pseudacris ornata (N=169), which have confirmed Bd infections. I use a logistic regression model to identify whether significant relationships exist between these two pathogens, disease, and death. I find that even amongst the most severely infected frogs, Ah is not detectable on the skin and only appears post-mortem. I therefore conclude that Ah is an opportunistic bacterial pathogen, scavenging on anurans only after mortality events. This research is the first known study to quantitatively assess Ah in amphibians in conjunction with Bd. While there is no causal relationship between these pathogens, future work will examine potential Ah infections in other organs to more fully understand the relationship between Bd and Ah.
Title: AEROMONAS HYDROPHILA IN AMPHIBIANS: HARMLESS BYSTANDER OR OPPORTUNISTIC PATHOGEN.
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Name(s): Rivas, Zachary P, Author
Savage, Anna Evangeline, Committee Chair
University of Central Florida, Degree Grantor
Type of Resource: text
Date Issued: 2016
Publisher: University of Central Florida
Language(s): English
Abstract/Description: For several decades amphibian populations have been declining. Historically, the bacterium A. hydrophila (Ah) was hypothesized to be the causal factor in amphibian disease and population declines. However, with the discovery of a chytrid fungus, Batrachochytrium dendrobatidis (Bd) in 1998, which was identified on the skin of amphibians during documented mortality events, Ah research became of minor interest as focus shifted to Bd. Recent studies into the immunocompromising abilities of Bd, however, have opened new questions about its relationship with Ah and their combined effects on a host. In this study, I explore the relationship between infection with these two pathogens, Bd and Ah, in two amphibian species from distinct regions of the United States. I developed a novel qPCR assay to measure the microbial load of Ah on the skin of two anuran species, Lithobates yavapaiensis (N=232) and Pseudacris ornata (N=169), which have confirmed Bd infections. I use a logistic regression model to identify whether significant relationships exist between these two pathogens, disease, and death. I find that even amongst the most severely infected frogs, Ah is not detectable on the skin and only appears post-mortem. I therefore conclude that Ah is an opportunistic bacterial pathogen, scavenging on anurans only after mortality events. This research is the first known study to quantitatively assess Ah in amphibians in conjunction with Bd. While there is no causal relationship between these pathogens, future work will examine potential Ah infections in other organs to more fully understand the relationship between Bd and Ah.
Identifier: CFH2000013 (IID), ucf:45589 (fedora)
Note(s): 2016-05-01
B.S.
College of Sciences, Biology
Bachelors
This record was generated from author submitted information.
Subject(s): co-infection
bacteria
fungus
amphibians
qPCR
Persistent Link to This Record: http://purl.flvc.org/ucf/fd/CFH2000013
Restrictions on Access: public
Host Institution: UCF

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