Infectious Diseases of Concern to Captive and Free-Ranging Wildlife in North America Updated Latest 2025–2026 Comprehensive Reference Resource for Wildlife Disease Ecology, Epidemiology, and Conservation Health Management with Key Insights and Case-Based

Infectious Disease Manual

Infectious Diseases of Concern to
Captive and Free Ranging Wildlife in
North America

An official publication of the
American Association of Zoo Veterinarians
Animal Health and Welfare Committee




Updated April 2020
Edited by
Paige Brock, DVM, DACZM, cVMA
Gretchen Cole, DVM, DACZM, DECZM (ZHM)
and
Richard Sim, DVM, DACZM

,Introduction:
This publication was designed as a starting reference point for information on the
infectious diseases that affect zoo and wild animal species captively housed or
free-ranging in North America. This volume complements a similar dynamic and
routinely-updated version that exists for the same populations in Europe. While
each sheet has been peer-reviewed, often by a topic expert, these fact sheets are not
intended to be used as an exclusive source of information, but rather provide quick
reference of basic disease properties and concerns. These fact sheets also highlight
diagnostics, laboratories, specialists, and treatment recommendations for clinicians,
pathologists, and wildlife biologists that encounter an infectious disease.

This compendium acts as a common resource and point of information for this discipline.



It is important to remember that these fact sheets are not to replace state or federal
regulations. As such, they are not legally enforceable documents or required
standards of care.

, American Association of Zoo Veterinarians Infectious Disease Manual
ACANTHAMOEBIASIS
Animal Transmission Clinical Severity Treatment Prevention Zoonotic
Group(s) Signs and Control
Affected
-Primates -Source: soil, -Cutaneous -Asymptomatic in Pentamidine - Difficult -Not
-Dogs water lesions immunecompetent isethionate; due to directly
-Sheep -Gains entry -Sinusitis individuals Sulfadiazine; ubiquitous transmitted
-Cattle via: breaks in -Pneumonitis Flucytosine; nature of -Can cause
-Horses skin; -Neurologic -Frequently fatal in Fluconazole; the disease in
-Kangaroos respiratory signs immunocompromised Itraconazole organism humans
-Birds tract; corneal -Fever individuals Amphotericin - Limit
-Reptiles surface; -Nausea B; exposure
-Amphibians hematogenous -Vomiting Azithromycin to dust,
-Fish spread to central soil, and
-Invertebrates nervous system water

Fact Sheet compiled by: Laurie Gage T




Sheet completed on: April 14, 2011; updated 19 March 2013.
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Fact Sheet Reviewed by: Kimberly Rainwater, Ariana Finkelstein
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Susceptible animal groups: Primates, dogs, sheep, cattle, horses, kangaroos, birds, reptiles, amphibians, fish,
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invertebrates.
Causative organism: Opportunistic protozoan parasites, Acanthamoeba spp. (A. castellanii, A. culbertsoni, A.
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hatchetti, A. healyi, A. polyphaga, A. rhysodes, A. astronyxis, A. divionensis)
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Zoonotic potential: May infect cornea of contact lens wearers and cause disseminated infection in
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immunocompromised individuals. T




Distribution: Ubiquitous worldwide. It may be found in soil; fresh and brackish water; bottled mineral water;
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cooling towers of electric and nuclear power plants; heating, ventilating, and air conditioning units, humidifiers;
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Jacuzzi tubs; hydrotherapy pools in hospitals; dental irrigation units; dialysis machines; dust in the air; bacterial,
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fungal , and mammalian cell cultures; contact lenses and ophthalmic saline flush; aural discharge; pulmonary
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secretions; feces. T




Incubation period: 1 day to 2 weeks T T T T T T




Clinical signs: Granulomatous amoebic encephalitis: depression, nausea, vomiting, low-grade fever, lethargy,
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cerebellar ataxia, visual disturbances, hemiparesis, cranial nerve deficits, seizures, and coma. Cutaneous
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lesions: ulcers, nodules, and subcutaneous abscesses. Respiratory: sinusitis and pneumonitis. Acanthamoeba
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keratitis (reported in humans only): ocular pain, photophobia, corneal ulceration, loss of visual acuity, and
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blindness.
Post mortem, gross, or histologic findings:
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Gross Findings: multifocal encephalomalacia and cerebral hemorrhage; nodular necrosis in the liver, kidney,
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lung, pancreas; multifocal granulomatous pneumonia; cutaneous granulomas
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Histologic Findings: Focal areas of necrosis and granulomatous inflammation in affected tissues; necrotizing
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vasculitis; [resence of cysts (12-16 um diameter) and trophozoites (14-40 um diameter) in affected tissues
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Diagnosis: Direct observation of amoebae in tissues stained with hematoxylin-eosin; indirect
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immunofluorescence staining using rabbit anti-amoeba sera; polymerase chain reaction to detect amoeba DNA T T T T T T T T T T T T



in tissue and cerebrospinal fluid samples; computed tomography and magnetic resonance imaging
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Material required for laboratory analysis: Serum, cerebrospinal fluid, formalin-fixed tissue samples, fresh
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tissue samples for culture (culture should only be done by accredited laboratories with the proper safety
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equipment)

, American Association of Zoo Veterinarians Infectious Disease Manual
ACANTHAMOEBIASIS

Relevant diagnostic laboratories:
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Centers for Disease Control and Prevention, Atlanta, Georgia
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Treatment: Pentamidine isethionate, sulfadiazine and other sulfa drugs, flucytosine, fluconazole, itraconazole,
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amphotericin B, and azithromycin. T T T




Prevention and control: Limit exposure to airborne soil particles that may carry cysts to the respiratory system;
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prevent exposure of open wounds to contaminated soil or water; preventative measures are especially important
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for immunocompromised individuals.
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Suggested disinfectant for housing facilities: Chlorhexidine, isopropyl alcohol (20%), hydrogen peroxide
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Notification Not required T T




Measures required under the Animal Disease Surveillance Plan None required
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Measures required for introducing animals to infected animal None required
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Conditions for restoring disease-free status after an outbreak: It is not possible due to ubiquitous nature of
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this organism.
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Experts who may be consulted Centers for Disease Control
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References:
1. Mehlhorn, H. 2008. Encyclopedia of Parasitology Volume 1, 3rd Ed. Springer-Verlag, New York. Pp: 2.
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2. Schuster, F.L., and G.S. Visvesvara. 2004. Amebae and ciliated protozoa as causal agents of waterborne
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zoonotic disease. Vet. Parasitol. 126: 91-120.T T T T T



3. Rutala, W.A., D.J. Weber, and the Healthcare Infection Control Practices Advisory Committee. 2008.
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Guideline for Disinfection and Sterilization in Healthcare Facilities, 2008.
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http://www.cdc.gov/hicpac/pdf/guidelines/Disinfection_Nov_2008.pdf. Accessed 14 April 2011. T T T T



4. Visvesvara, G.S., H. Moura, and F L. Schuster. 2007. Pathogenic and opportunistic free-living amoebae:
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Acanthamoeba spp., Balamuthia mandrillaris, Naegleria fowleri, and Sappinia diploidea. FEMS
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Immunol. Med. Microbiol. 50: 1-26. T T T T