Disease dynamics, invasion and biological control of environmentally growing pathogens

Research output: ThesisDoctoral ThesisCollection of Articles

Abstract

Many existing and emerging microbial infectious diseases are caused by environmentally growing opportunist pathogens. These pathogens are, contrary to obligatory pathogens, able to survive and replicate in the outside-host environment as free-living microbes that use within-host growth as an alternative replication strategy. This disease class has eco-evolutionary implications in natural populations and causes a serious health and economical threat to humans, our food production and to wildlife. Because of the ability of environmentally growing opportunists to survive and replicate independently of hosts, these diseases are hard to eradicate with conventional methods. The conditions that favor or disfavor environmental opportunism are still poorly understood. Better understanding of the dynamics of these diseases is needed in order to develop proper control methods against them. In this thesis I have developed novel epidemiological models to describe the disease dynamics of environmentally growing pathogens. These models modify the traditional Susceptible-Infected host (SI-model) framework by combining it to the outside-host community of an environmentally growing pathogen. I have considered how the environmental growth of the pathogens and the antagonistic ecological interactions these pathogens face in the outside-host environment, such as competition, predation and parasitism, affect the disease dynamics, invasion of novel pathogens and biological control of environmentally growing infectious diseases. The analyses show that the disease dynamics of environmentally growing pathogens differ from obligatory pathogens. Importantly, ability to grow in the outside-host environment promotes disease outbreaks and can lead to the extinction of the host, which is untypical in the case of obligatory pathogens. Antagonistic interactions the pathogen faces in the outside-host environment can on the other hand limit disease outbreaks and prevent extinction of the hosts that would otherwise occur due to the disease. I conclude that the eradication can be accomplished 1) by increasing the outside-host competition, 2) through predation of pathogens, or 3) through viral infections in pathogens.
Original languageEnglish
Place of PublicationHelsinki
Publisher
Print ISBNs978-951-51-2077-9
Electronic ISBNs978-951-51-2078-6
Publication statusPublished - 29 Apr 2016
MoE publication typeG5 Doctoral dissertation (article)

Fields of Science

  • 1184 Genetics, developmental biology, physiology

Cite this

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title = "Disease dynamics, invasion and biological control of environmentally growing pathogens",
abstract = "Many existing and emerging microbial infectious diseases are caused by environmentally growing opportunist pathogens. These pathogens are, contrary to obligatory pathogens, able to survive and replicate in the outside-host environment as free-living microbes that use within-host growth as an alternative replication strategy. This disease class has eco-evolutionary implications in natural populations and causes a serious health and economical threat to humans, our food production and to wildlife. Because of the ability of environmentally growing opportunists to survive and replicate independently of hosts, these diseases are hard to eradicate with conventional methods. The conditions that favor or disfavor environmental opportunism are still poorly understood. Better understanding of the dynamics of these diseases is needed in order to develop proper control methods against them. In this thesis I have developed novel epidemiological models to describe the disease dynamics of environmentally growing pathogens. These models modify the traditional Susceptible-Infected host (SI-model) framework by combining it to the outside-host community of an environmentally growing pathogen. I have considered how the environmental growth of the pathogens and the antagonistic ecological interactions these pathogens face in the outside-host environment, such as competition, predation and parasitism, affect the disease dynamics, invasion of novel pathogens and biological control of environmentally growing infectious diseases. The analyses show that the disease dynamics of environmentally growing pathogens differ from obligatory pathogens. Importantly, ability to grow in the outside-host environment promotes disease outbreaks and can lead to the extinction of the host, which is untypical in the case of obligatory pathogens. Antagonistic interactions the pathogen faces in the outside-host environment can on the other hand limit disease outbreaks and prevent extinction of the hosts that would otherwise occur due to the disease. I conclude that the eradication can be accomplished 1) by increasing the outside-host competition, 2) through predation of pathogens, or 3) through viral infections in pathogens.",
keywords = "1184 Genetics, developmental biology, physiology",
author = "Ilona Merikanto",
year = "2016",
month = "4",
day = "29",
language = "English",
isbn = "978-951-51-2077-9",
publisher = "Helsingin yliopisto",
address = "Finland",

}

Disease dynamics, invasion and biological control of environmentally growing pathogens. / Merikanto, Ilona.

Helsinki : Helsingin yliopisto, 2016. 51 p.

Research output: ThesisDoctoral ThesisCollection of Articles

TY - THES

T1 - Disease dynamics, invasion and biological control of environmentally growing pathogens

AU - Merikanto, Ilona

PY - 2016/4/29

Y1 - 2016/4/29

N2 - Many existing and emerging microbial infectious diseases are caused by environmentally growing opportunist pathogens. These pathogens are, contrary to obligatory pathogens, able to survive and replicate in the outside-host environment as free-living microbes that use within-host growth as an alternative replication strategy. This disease class has eco-evolutionary implications in natural populations and causes a serious health and economical threat to humans, our food production and to wildlife. Because of the ability of environmentally growing opportunists to survive and replicate independently of hosts, these diseases are hard to eradicate with conventional methods. The conditions that favor or disfavor environmental opportunism are still poorly understood. Better understanding of the dynamics of these diseases is needed in order to develop proper control methods against them. In this thesis I have developed novel epidemiological models to describe the disease dynamics of environmentally growing pathogens. These models modify the traditional Susceptible-Infected host (SI-model) framework by combining it to the outside-host community of an environmentally growing pathogen. I have considered how the environmental growth of the pathogens and the antagonistic ecological interactions these pathogens face in the outside-host environment, such as competition, predation and parasitism, affect the disease dynamics, invasion of novel pathogens and biological control of environmentally growing infectious diseases. The analyses show that the disease dynamics of environmentally growing pathogens differ from obligatory pathogens. Importantly, ability to grow in the outside-host environment promotes disease outbreaks and can lead to the extinction of the host, which is untypical in the case of obligatory pathogens. Antagonistic interactions the pathogen faces in the outside-host environment can on the other hand limit disease outbreaks and prevent extinction of the hosts that would otherwise occur due to the disease. I conclude that the eradication can be accomplished 1) by increasing the outside-host competition, 2) through predation of pathogens, or 3) through viral infections in pathogens.

AB - Many existing and emerging microbial infectious diseases are caused by environmentally growing opportunist pathogens. These pathogens are, contrary to obligatory pathogens, able to survive and replicate in the outside-host environment as free-living microbes that use within-host growth as an alternative replication strategy. This disease class has eco-evolutionary implications in natural populations and causes a serious health and economical threat to humans, our food production and to wildlife. Because of the ability of environmentally growing opportunists to survive and replicate independently of hosts, these diseases are hard to eradicate with conventional methods. The conditions that favor or disfavor environmental opportunism are still poorly understood. Better understanding of the dynamics of these diseases is needed in order to develop proper control methods against them. In this thesis I have developed novel epidemiological models to describe the disease dynamics of environmentally growing pathogens. These models modify the traditional Susceptible-Infected host (SI-model) framework by combining it to the outside-host community of an environmentally growing pathogen. I have considered how the environmental growth of the pathogens and the antagonistic ecological interactions these pathogens face in the outside-host environment, such as competition, predation and parasitism, affect the disease dynamics, invasion of novel pathogens and biological control of environmentally growing infectious diseases. The analyses show that the disease dynamics of environmentally growing pathogens differ from obligatory pathogens. Importantly, ability to grow in the outside-host environment promotes disease outbreaks and can lead to the extinction of the host, which is untypical in the case of obligatory pathogens. Antagonistic interactions the pathogen faces in the outside-host environment can on the other hand limit disease outbreaks and prevent extinction of the hosts that would otherwise occur due to the disease. I conclude that the eradication can be accomplished 1) by increasing the outside-host competition, 2) through predation of pathogens, or 3) through viral infections in pathogens.

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M3 - Doctoral Thesis

SN - 978-951-51-2077-9

PB - Helsingin yliopisto

CY - Helsinki

ER -