An epidemiologic approach to free-ranging wood duck (Aix sponsa) health assessment

Winter, John Mark

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https://hdl.handle.net/2142/129266 Copy

Description

Title

An epidemiologic approach to free-ranging wood duck (Aix sponsa) health assessment

Author(s)

Winter, John Mark

Issue Date

2025-05-08

Director of Research (if dissertation) or Advisor (if thesis)

Allender, Matthew C

Committee Member(s)

• Langan, Jennifer N
• Anchor, Chris

Department of Study

Vet Clinical Medicine

Discipline

VMS-Veterinary Clinical Medcne

Degree Granting Institution

University of Illinois Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• wood duck
• Aix sponsa
• epidemiology
• wildlife health
• adenovirus
• Riemerella anatipestifer
• hematology
• plasma biochemistry
• protein electrophoresis
• reference intervals

Abstract

The wood duck (Aix sponsa) is a medium-sized perching duck and is one of the five most commonly harvested waterfowl species in the Mississippi Flyway. However, this species was threatened with extinction in the early 1900’s due to habitat loss combined with unregulated hunting practices and has only recovered with the help of extensive hunting limitations, habitat restoration, and the implementation of nationwide wood duck nest box installation programs. This study set out to perform a comprehensive health assessment for normal baseline characterization of wood duck health and identification of possible wood duck disease threats for the first time in the North American Mississippi Flyway. Physical examination, complete blood counts, plasma biochemistry, protein electrophoresis (capillary zone electrophoresis and agarose gel electrophoresis), and pathogen surveillance via PCR was performed on 253 free-ranging wood ducks over August and September of 2022-2024 in northeastern Illinois. The most common clinical abnormalities observed included: beak abrasions (n = 118, 48%), pododermatitis (n = 32, 13%), small defects (circular or irregular holes) in the interdigital webbing of the feet (n = 20, 8%), sinus arrhythmia on cardiac auscultation (n = 10, 4%), small abrasions/wounds on the face or head (n=9, 4%), auscultated pulmonary crackles (n = 8, 3%), and raised nodules on toes and feet webbing (n = 7, 3%). The four diagnosed pathogens via PCR included duck hepatitis B virus (n = 20, 12%), Riemerella anatipestifer (n = 87, 51.2%), an adenovirus previously isolated from a Pacific black duck (Anas superciliosa; n = 7, 3%, referred to in this study as PBDA1), and a novel adenovirus hereafter referred to as wood duck adenovirus 1 (WDA1; n = 4, 2%). A single individual with WDA1 was observed with an oral ulcer, but no other pathogens were associated with clinical lesions or bloodwork changes. Hemoparasites morphologically consistent with Haemoproteus spp. and Plasmodium spp. were commonly diagnosed (n = 98, 62.4%) with no associated clinical abnormalities. References ranges for complete blood counts, plasma biochemistry, plasma vitamin levels, capillary zone electrophoresis and agarose gel electrophoresis were created from 163 wood ducks. This study serves as an epidemiologic study template for future waterfowl health assessments and helps provide baseline information critical for success of future wood duck conservation medicine efforts.

Graduation Semester

2025-05

Type of Resource

Thesis

Handle URL

https://hdl.handle.net/2142/129266

Copyright and License Information

Copyright 2025 John Winter

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