All images are from the FWS Image Library unless otherwise noted.

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• All images are from the FWS Image Library unless
  otherwise noted.

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Wildlife Diseases

• Chapter 8

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• Disease
• disturbance to normal function or structure of an
  animal
• Causes
• infectious
• pathogens
• bacteria, viruses, rikettsias, parasites, fungi
• parasitic
• toxic
• physiological
• nutritional
• congenital
• degenerative
• Epizootiology
• how and why of diseases

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• Enzootic
• chronic disease
• Epizootic
• eruptive states of disease

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Why Study Wildlife Diseases?

• Reservoirs or vectors for pathogens infecting
  domestic animals
• brucellosis
• Montana and Yellowstone fear
• Density of animal populations
• habitat decreases, density increases, disease
  increases
• Diseases may cause serious losses in already
  small populations of endangered species
• whooping cranes
• canine parvovirus and wolves at Isle Royale
• Diseases part of spectrum of issues facing
  wildlife mgrs.
• Ways to estimate health of populations

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Wildlife Diseases

• Avian cholera
• Tularemia
• Brucellosis
• Sylvatic plague
• Duck virus
• Infectious hemotopeotic necrosis
• Aspergillosis
• Sarcoptic mange

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Perspectives

• Disease as natural phenomena
• Some severely affect wildlife populations
• Implications for domestic animals
• Implications for hunting
• quit hunting that species
• hunt elsewhere
• reduced time hunting
• Management tools
• alter hunting dates
• infected animals die
• parasites leave host

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Figure 8-2 Botfly Larvae
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Table 8-1 Wildlife Diseases
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Table 8-2
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Table 8-3 Management Responses to Wildlife
Disease
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Diseases and Habitat

• Habitat conditions influence the course of many
  diseases
• Habitat manipulations
• wildlife medicine
• Avian botulism
• linked with habitat conditions
• dead organic matter, high temperatures, alkaline
  environment related to toxin production
• sludge-bed hypothesis
• microenviroment concept
• wetland invertebrates prime transmitters
• maggot cycle
• manipulate water levels to remain constant during
  season

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Figure 8-5 Epizootiology of Botulism
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Diseases and Populations

• Disease effecting regulatory controls
• Insufficient data to assess impact of pathogens
• sampling difficulties
• interactions of disease with predation
• Density-dependent mechanism
• higher density, grater incidence of disease
• Management
• lace food with medicine
• prevent disease in unborn ewes lambs
• treating symptoms, overcrowding

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Figure 8-8 Infection vs. Densities
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Figure 8-9 Schematic Infections
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Diseases and Biological Controls

• Australian exotics
• European rabbit overpopulation/overgrazing
• disease myxomatosis (poxvirus)
• resistance developed
• rabbit calicivirus disease used in 1996
• wholesale elimination of rabbits may disrupt food
  chain
• Bluetongue
• viral disease
• connected with domestic grazing, carried vectors
• utilized arthropod vector to immunize desert
  bighorns

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Lyme Disease Emerging Diseases

• AIDS
• Hantavirus
• deer mice droppings
• Conjunctivitis in birds spreading across NA
• Lyme disease
• arthropod-borne disease
• deer tick
• may be caused by ecological changes
• reversal of abandoned farms to early forest
  succession

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• Preventing Lyme disease
• inspect for ticks after outdoor activities
• promptly removing ticks with tweezers
• wear light-colored clothing
• ticks are more visible
• use insect repellents
• insert pant cuffs inside tops of socks

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Wildlife Diseases and Humans

• Wildlife populations
• reservoirs
• carriers
• Examples
• bubonic plague
• rodents
• sylvatic plague
• rodents carriers for bobcats, badgers,etc. fleas
  vectors
• tularemia
• ticks/arthropods feeding on infected rabbits
• rabies

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Table 8-4 Rabies in Raccoons
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Summary

• Epizootiology
• how
• why
• Ecological conditions
• habitat quality
• habitat quantity
• Density dependent mechanism
• Emerging Diseases
• Lyme disease