Fungal pathogens in captive and free ranging wild animal conservation programs LuisR Padilla DVM Dipl ACZM Smithsonian Conservation Biology Institute National Zoological Park 1500 Remount Road Front Royal, VA 22630
Background The Smithsonian Conservation Biology Institute of the National Zoological Park serves as the umbrella for research effortsto conserve endangered species through captive breeding, research and free ranging studies
Captive Propagation Ideally, species are conserved in the wild Captive breeding a viable short term solution until threats to population can be mitigated Captivebreeding could be a way to supplement populations or a reservoir of genetic material against extinction
Captive Propagation may mitigate the effects of threats we cannot currently control Disease in this case fungi Climate change Natural disasters threats that can occur too quickly Habitat loss Pollution Poaching, Collection for animal trade Competition or predation by introduced species
In trying to accomplish our goal Fungal pathogens may be a threat that develops as spontaneous infections Fungal pathogens may be the reason a captive propagation program is undertaken Investigation of fungal diseases, diagnostics or treatments may be the reason for establishing a captive colony
Common fungal diseases in non-domestic animals Aspergillosis Blastomycosis Chromoblastomycosis Coccidioides Cryptococcosis Sporotrichosis Saprolegniasis Chytridiomycosis Chrysosporum Nanniziopsis Fusarium sp. Geomyces sp Lobomycosis Histoplasmosis Dermatophytosis Candidiasis Basidiobolus Mucor sp Conidiobolus Malassezia sp Mycotoxicosis*
Fungi infections in species recovery programs Opportunistic or secondary infections Immunosuppresion (ie Aspergillus, Candida) Limited immune function (Coccidioides in P horses) Opportunistic invaders (Saprolegnia, Candida, Dermatophytes) Primary Pathogens, often seen as emerging diseases Chytridiomycosis in amphibians Chrysosporium in reptiles Geomyces in reptiles, bats Fungal dermatitis in marine mammals Burbot reproductive disease Experimental Infections, done to develop treatment modalities or study disease mechanisms Chytridiomycosis Chrysosporium anamorph of Nanniziopsis vriesii
What captive populations can teach us about fungi Host responses, organ affinity Epidemiology of infections Emerging diseases 1991 mystery fungal disease in Arroyo toads noted by National Zoo pathologists, would be described as phylum Chytridiomycota in 1999 Species susceptibility Strains Treatment Diagnostic capabilities National Zoological Park
Captive models of disease Experimental populations can be used to study development of disease Animals can be natural models of disease and may elucidate important host defense mechanisms New pathogens may be detected in captive specimens, as carcass usually recoverable Photo by Lisa Ware
Przewalskii s horses: Coccidioides Disproportionately high prevalence of disease in endemic areas in Przewalskii s horses High morbidity and mortality Younger horses Immune system of P horses may fail to respond to coccidioides infection (Lymphocytes fail to proliferate in response to Coccidioides) Terio et al. JZWM (2003) 34:339-345 Vet.uga.edu NZP Photo, M. Murphy
Japanese Giant Salamanders Imported from Japan Tested negative for Bd prior to export Tested positive for Bd during quarantine May have own haplotype of Bd, with no clinical signs (ongoing) Culture? NZP Photo, M. Murphy
Japanese Giant Salamanders 4 JGS treated with itraconazole oral, baths successfully Biosecurity maintained NZP Photo, Dept Animal Health NZP Photo, Dept Animal Health
In the wild: burbot (Lota lota) NZP pathologist (Tim Walsh) working since 1996 In Pacific NW and SW Canada, may be affected by uncultured, novel fungus Fungus has an affinity for gonads and reproductive tissue Work in progress
Chrysosporium in reptiles Considered an emerging disease of captive and wild reptiles Can not be grouped as one disease entity, multiple species, and host-relationship being elucidated Primary pathogens of reptiles Asymptomatic carriers likely for some, which is a concern to mixed species collections
Threat of White Nose Syndrome 2009 Projected southward spread of white nose syndrome into range of VA Big Eared Bat in winter 2009 Action plan developed to try to establish a small, experimental rescue population prior to WNS entering range Photo Credit: USFWS
Captive breeding Is not feasible for all species for purposes of recovering populations Can be challenging, may not be cost-effective True value of a species or cost of recovery is difficult to estimate
Experimental Work: J lividum in Atelopus zeteki Matthew H. Becker, Reid N. Harris, Kevin P. C. Minbiole, Christian R. Schwantes, Louise A. Rollins-Smith, Laura K. Reinert, Robert M. Brucker, Brian Gratwicke J. lividum conveys anti-chytridiomycotic protection in Rana muscosa PRELIMINARY RESULTS: It was used to in captive-bred Panamanian golden frogs (Atelopus zeteki) infected with Bd., but was unsuccessful in preventing mortality Analysis of Bd infection intensity and J. lividum colonization suggest that probiotic colonization may have provided some initial protection, but not as strong as J. lividum cell numbers declined.
Take Home Messages Fungal diseases pose a risk to the extinction of major vertebrate groups Captive recovery efforts can contribute to understanding fungal disease dynamics and may be important to the preservation of some species Comparative medicine approach to improve diagnostics and recognition of disease in wild species essential to managing emerging fungal diseases in wildlife populations Recognition of diseases in captive or free ranging animal populations may be an early indicator of emerging diseases The extent of a threat to populations is often not known early in the detection process or threat not identified until it is too late