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" The relevance of Hayek's theory of the trade cycle for understanding the United Kingdom business cycle "
Whittle, Richard Robert
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Latin Dissertation
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| Language of Document
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English
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| Record Number
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1058647
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| Doc. No
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TL57764
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| Main Entry
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Dwight, Ian Alexander
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| Title & Author
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Pathogen Surveillance in Wild and Pen-Reared Ring-Necked Pheasants (Phasianus colchicus) in California\ Dwight, Ian AlexanderPitesky, Maurice E.
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| College
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University of California, Davis
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| Date
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2020
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| Degree
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M.S.
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2020
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| Note
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60 p.
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| Abstract
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The release of captive-reared animals into wildlife habitat may have unintended consequences including the introduction of novel pathogens to the environment. Many studies focus on the protection of domesticated species from wildlife, but the impacts of disease on wildlife populations are not generally considered in the context of releasing animals reared in captivity. Releasing pen-reared game birds such as the ring-necked pheasant (Phasianus colchicus) onto public and private wildlands is a common management practice, often for the purpose of augmenting local pheasant populations, that may provide a mechanism by which novel disease agents can be disseminated into the environment. This study presents findings that characterize pathogen exposure, as well as make inference to the potential of detecting these pathogens, in a sample of pen-reared pheasants from game bird breeding farms, as well as wild pheasants from public and private wildlands in California. Serological data were collected from three sources, which consisted of: (1) pen-reared pheasants from seven game bird breeding farms, (2) previously released pen-reared pheasants captured at two study sites where wild pheasants occurred, and (3) wild pheasants captured across six study sites in California during 2014–2017. In pen-reared pheasants sampled across breeding farms (n = 71) antibodies were detected via enzyme-linked immunosorbent assay against hemorrhagic enteritis virus (HEV; 66%), infectious laryngotracheitis (ILT; 13%), infectious bursal disease virus (IBDV; 24%), paramyxovirus type 1 (PMV-1; 10%), and Pasteurella multocida (PM; 8%). Previously released pen-reared pheasants captured at our study sites (n = 6) were seropositive for HEV (33%), ILT (50%), and PM (100%). Wild pheasants (n = 79) were seropositive for HEV (29%), ILT (1%), IBDV (34%), PMV-1 (8%), and PM (30%). To go beyond pathogen exposure and detect infection, necropsy and ancillary diagnostics were performed in addition to serological testing on 40 of the 71 pen-reared pheasants sampled from five of the seven farms. Owners from these five farms were subsequently interviewed and asked a specific set of questions related to husbandry and biosecurity practices on the farm. Pheasants from three of these farms were positive by polymerase chain reaction for Siadenovirus, the causative agent of both hemorrhagic enteritis in turkeys and marble spleen disease (MSD) of pheasants, which are genetically similar and serologically indistinguishable. Based on serological surveillance, both wild and pen-reared pheasants appear to be exposed to similar pathogens, making it difficult to demonstrate a causative link based on the serological data analyzed in both populations. Whole genome sequencing would be a logical step forward in distinguishing HEV from MSD and to trace the origin of pathogens from farm to environment. Nonetheless, the release of pen-reared pheasants and other game birds for recreation may facilitate pathogen introductions to wild pheasant populations, and perhaps other wildlife, which warrants further investigation.
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| Descriptor
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Animal diseases
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Ecology
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Wildlife conservation
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| Added Entry
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Pitesky, Maurice E.
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University of California, Davis
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