• A highly divergent picornavirus infecting the gut epithelia of zebrafish (Danio rerio) in research institutions worldwide

      Altan, Eda; Kubiski, Steven V.; Boros, Ákos; Reuter, Gábor; Sadeghi, Mohammadreza; Deng, Xutao; Creighton, Erica K.; Crim, Marcus J.; Delwart, Eric (2019)
      Zebrafish have been extensively used as a model system for research in vertebrate development and pathogen–host interactions. We describe the complete genome of a novel picornavirus identified during a viral metagenomics analysis of zebrafish gut tissue....
    • Anthropogenic change alters ecological relationships via interactive changes in stress physiology and behavior within and among organisms

      Hammond, Talisin T.; Ortiz-Jimenez, Chelsea A; Smith, Jennifer E (2020)
      ...Human-induced changes in the stress physiology of one species and the downstream impacts on behavior can therefore interact with the physiological and behavioral responses of other organisms to alter emergent ecological phenomena. Here, we highlight three scenarios in which the stress physiology and behavior of individuals on different sides of an ecological relationship are interactively impacted by anthropogenic change....
    • Bovidae, Antilocapridae, Giraffidae, Tragulidae, Hippopotamidae

      Jones, Megan E. B.; Gasper, D.J.; Mitchell, E.; Terio, Karen A.; McAloose, Denise; St. Leger, Judy (Academic PressSan Diego, CA, 2018)
    • Case series: clinical salmonellosis in four black rhinoceros (diceros bicornis) calves

      Love, David; Madrigal, Rodolfo; Cerveny, Shannon; Raines, Janis; Rideout, Bruce; Lung, Nancy P. (2017)
      Although Salmonella spp. infection has been identified in captive and free-ranging rhinoceros, clinical cases in black rhinoceros (Diceros bicornis) calves have not been described. This case series describes clinical salmonellosis in four black rhinoceros calves....
    • Causes of mortality in anuran amphibians from an ex-situ survival assurance colony in Panama

      Pessier, Allan P.; Baitchman, E.J.; Crump, P.; Wilson, B.; Griffith, E.; Ross, H. (2014)
      …This study reviewed postmortem findings in 167 frogs from 13 species that died in a large Panamanian rescue and survival assurance population between 2006 and 2011…. Applied research efforts to improve sustainability of survival assurance populations should focus on elucidating optimal husbandry practices for diverse species, improving methods for nutritional supplementation of cultured insects and examination of the role of water composition in disease development.
    • Early 1900s Detection of Batrachochytrium dendrobatidis in Korean Amphibians

      Fong, Jonathan J.; Cheng, Tina L.; Bataille, Arnaud; Pessier, Allan P.; Waldman, Bruce; Vredenburg, Vance T. (2015)
      The pathogenic fungus Batrachochytrium dendrobatidis (Bd) is a major conservation concern because of its role in decimating amphibian populations worldwide. We used quantitative PCR to screen 244 museum specimens from the Korean Peninsula, collected between 1911 and 2004, for the presence of Bd to gain insight into its history in Asia. Three specimens of Rugosa emeljanovi (previously Rana or Glandirana rugosa), collected in 1911 from Wonsan, North Korea, tested positive for Bd. Histology of these positive specimens revealed mild hyperkeratosis – a non-specific host response commonly found in Bd-infected frogs – but no Bd zoospores or zoosporangia. Our results indicate that Bd was present in Korea more than 100 years ago, consistent with hypotheses suggesting that Korean amphibians may be infected by endemic Asian Bd strains.
    • Early-life exposures and Johne’s disease risk in zoo ruminants

      Burgess, Tristan L.; Witte, Carmel L.; Rideout, Bruce (2017)
      Johne’s disease, caused by Mycobacterium avium subsp. paratuberculosis (MAP), is a chronic, progressive bacterial enteritis of ruminants that can cause serious losses in both livestock and exotic species. Infection risk in exotic ruminants is associated with maternal infection status, but the effect of other herdmates on risk of infection has not been reported, to our knowledge....
    • First evidence of amphibian chytrid fungus (Batrachochytrium dendrobatidis) and ranavirus in Hong Kong amphibian trade

      Kolby, Jonathan E.; Smith, Kristine M.; Berger, Lee; Karesh, William B.; Preston, Asa; Pessier, Allan P.; Skerratt, Lee F. (2014)
      The emerging infectious amphibian diseases caused by amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) and ranaviruses are responsible for global amphibian population declines and extinctions. Although likely to have been spread by a variety of activities, transcontinental dispersal appears closely associated with the international trade in live amphibians. The territory of Hong Kong reports frequent, high volume trade in amphibians, and yet the presence of Bd and ranavirus have not previously been detected in either traded or free-ranging amphibians. In 2012, a prospective surveillance project was conducted to investigate the presence of these pathogens in commercial shipments of live amphibians exported from Hong Kong International Airport. Analysis of skin (Bd) and cloacal (ranavirus) swabs by quantitative PCR detected pathogen presence in 31/265 (11.7%) and in 105/185 (56.8%) of amphibians, respectively. In addition, the water in which animals were transported tested positive for Bd, demonstrating the risk of pathogen pollution by the disposal of untreated wastewater. It is uncertain whether Bd and ranavirus remain contained within Hong Kong’s trade sector, or if native amphibians have already been exposed. Rapid response efforts are now urgently needed to determine current pathogen distribution in Hong Kong, evaluate potential trade-associated exposure to free-ranging amphibians, and identify opportunities to prevent disease establishment.
    • Hepatitis and splenitis due to systemic tetratrichomoniasis in an American white pelican (Pelecanus erythrorhynchos)

      Burns, Rachel E.; Braun, Josephine; Armién, Aníbal G.; Rideout, Bruce (2013)
      A free-ranging, young adult, female American white pelican (Pelecanus erythrorhynchos), found dead on the grounds of the San Diego Zoo Safari Park in Southern California, had severe multifocal to coalescing necrotizing hepatitis and splenitis on postmortem examination. Histologically, within the large areas of necrosis were myriad pleomorphic, 5–20 µm in diameter, protozoal organisms with 1 to multiple nuclei. Ultrastructurally, the organisms were consistent with a trichomonad flagellate. Polymerase chain reaction and sequencing of the small subunit ribosomal RNA gene identified nucleotide sequences with 99% identity to Tetratrichomonas gallinarum, which is a common inhabitant of the intestinal tract of galliform and anseriform birds that has occasionally been associated with disease, including typhlitis and hepatitis. Damage to the cecal mucosa in the pelican from trematodes and secondary bacterial infection could have allowed invasion and systemic dissemination of the organism. Exposure of the pelican to a variety of native and exotic anseriform and galliform birds at the zoological institution could have led to cross-species infection and severe manifestation of disease in a novel host.
    • Histopathologic findings in free-ranging California hummingbirds, 1996–2017

      Magagna, Michelle; Noland, Erica; Tell, Lisa A.; Purdin, Guthrum; Rideout, Bruce; Lipman, Max W.; Agnew, Dalen (2018)
      A histopathologic study of free-ranging hummingbirds in California was performed to identify mortality trends. Tissues from 61 wild hummingbirds representing five native California species collected by the San Diego Zoo from 1996 to 2016 or the Lindsay Wildlife Experience from 2015 to 2017 were histologically examined....
    • Hopping over red leg: The metamorphosis of amphibian pathology

      Pessier, Allan P. (2017)
      It wasn’t very long ago that the only disease of amphibians that students might hear about in veterinary school was “red leg syndrome,” attributed to infections with the bacterium Aeromonas hydrophila.... This would begin to change with recognition of the “Amphibian Extinction Crisis.” ....
    • Laboratory diagnostics

      Rideout, Bruce; Braun, Josephine; Pessier, Allan P.; Terio, Karen A.; McAloose, Denise; St. Leger, Judy (Academic PressSan Diego, CA, 2018)
      This chapter focuses on the challenges of using laboratory diagnostics in wildlife and how to choose an appropriate test and interpret the results. Very few diagnostic tests have been validated for use in wildlife, which creates challenges for the diagnostician because some of these tests must be used anyway, while others should be avoided....
    • Leaping forward in amphibian health and nutrition

      Olea-Popelka, Francisco; Ferrie, Gina M.; Morris, Cheryl; Pessier, Allan P.; Schad, Kristine; Stamper, M. Andrew; Gagliardo, Ron; Koutsos, Elizabeth; Valdes, Eduardo V. (2014)
      …In this manuscript, we describe and summarize the outcomes of this workshop with regards (a) the identified gaps in knowledge, (b) identified priorities for closing these gaps, and (c) compile a list of actions to address these priorities. Four general areas of improvement were identified in relation to how measurements are currently being taken to evaluate ex situ amphibian health: nutrition, infectious diseases, husbandry, and integrated biology including genetics and endocrinology….
    • Leukoencephalomyelopathy of mature captive cheetahs and other large felids: A novel neurodegenerative disease that came and went?

      Brower, A. I.; Munson, L.; Radcliffe, R. W.; Citino, S. B.; Lackey, L. B.; Van Winkle, T. J.; Stalis, Ilse H.; Terio, K. A.; Summers, B. A.; de Lahunta, A. (2014)
      A novel leukoencephalomyelopathy was identified in 73 mature male and female large captive felids between 1994 and 2005. While the majority of identified cases occurred in cheetahs (Acinonyx jubatus), the disease was also found in members of 2 other subfamilies of Felidae: 1 generic tiger (Panthera tigris) and 2 Florida panthers (Puma concolor coryi). The median age at time of death was 12 years, and all but 1 cheetah were housed in the United States. Characteristic clinical history included progressive loss of vision leading to blindness, disorientation, and/or difficulty eating. Neurologic deficits progressed at a variable rate over days to years. Mild to severe bilateral degenerative lesions were present in the cerebral white matter and variably and to a lesser degree in the white matter of the brain stem and spinal cord. Astrocytosis and swelling of myelin sheaths progressed to total white matter degeneration and cavitation. Large, bizarre reactive astrocytes are a consistent histopathologic feature of this condition. The cause of the severe white matter degeneration in these captive felids remains unknown; the lesions were not typical of any known neurotoxicoses, direct effects of or reactions to infectious diseases, or nutritional deficiencies. Leukoencephalomyelopathy was identified in 70 cheetahs, 1 tiger, and 2 panthers over an 11-year period, and to our knowledge, cases have ceased without planned intervention. Given what is known about the epidemiology of the disease and morphology of the lesions, an environmental or husbandry-associated source of neurotoxicity is suspected., A novel leukoencephalomyelopathy was identified in 73 mature male and female large captive felids between 1994 and 2005. While the majority of identified cases occurred in cheetahs (Acinonyx jubatus), the disease was also found in members of 2 other subfamilies of Felidae: 1 generic tiger (Panthera tigris) and 2 Florida panthers (Puma concolor coryi). The median age at time of death was 12 years, and all but 1 cheetah were housed in the United States. Characteristic clinical history included progressive loss of vision leading to blindness, disorientation, and/or difficulty eating. Neurologic deficits progressed at a variable rate over days to years. Mild to severe bilateral degenerative lesions were present in the cerebral white matter and variably and to a lesser degree in the white matter of the brain stem and spinal cord. Astrocytosis and swelling of myelin sheaths progressed to total white matter degeneration and cavitation. Large, bizarre reactive astrocytes are a consistent histopathologic feature of this condition. The cause of the severe white matter degeneration in these captive felids remains unknown; the lesions were not typical of any known neurotoxicoses, direct effects of or reactions to infectious diseases, or nutritional deficiencies. Leukoencephalomyelopathy was identified in 70 cheetahs, 1 tiger, and 2 panthers over an 11-year period, and to our knowledge, cases have ceased without planned intervention. Given what is known about the epidemiology of the disease and morphology of the lesions, an environmental or husbandry-associated source of neurotoxicity is suspected.
    • Low MHC variation in the polar bear: Implications in the face of Arctic warming?

      Weber, D.S.; Van Coeverden de Groot, P.J.; Schrenzel, Mark D.; Perez, D.A.; Thomas, S. (2013)
      Animals in the Arctic have low pathogen diversity but with rapid climate warming, this is expected to change. One insidious consequence of climate change is exposure of Arctic species to new pathogens derived from more southern species expanding their range northward. To assess potential vulnerability of polar bears to disease exposure, we examined genetic variation in major histocompatibility complex (MHC) loci (part of immune system) in Canadian polar bears and found low genetic diversity, consistent with long?standing exposure to low pathogen/parasite loads....
    • On the timing of an epidemic of amphibian chytridiomycosis in the highlands of Guatemala

      Mendelson, Joseph R.; Jones, Megan E. B.; Pessier, Allan P.; Toledo, Gabriela; Kabay, Edward H.; Campbell, Jonathan A. (2014)
      We analyzed museum specimens from two regions of Guatemala for the presence of the pathogenic amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) using both histological and PCR-based assays. We determined that the pathogen was present at one site at low prevalence in 1980 and 1981, immediately preceding drastic declines of amphibian in the region by 1983….
    • Pathologic changes associated with suspected hypovitaminosis A in amphibians under managed care

      Rodríguez, Carlos E.; Pessier, Allan P. (2014)
      Vitamin A deficiency is a recently recognized nutritional disease in amphibians fed insect-based diets…. This review highlights the need to establish standardized guidelines for optimal postmortem tissue sampling of amphibians in order to maximize the accurate diagnosis of pathologic lesions that may be associated with hypovitaminosis A.
    • Prosimians

      McAloose, Denise; Stalis, Ilse H.; Terio, Karen A.; McAloose, Denise; St. Leger, Judy (Academic PressSan Diego, CA, 2018)
    • Pulmonary hyalinosis in captive sugar gliders (Petaurus breviceps)

      Sokol, Set A.; Agnew, Dalen W.; Lewis, Anne D.; Southard, Teresa L.; Miller, Andrew D. (2017)
      ...Lung lesions resembling pulmonary hyalinosis were observed in 6 captive adult sugar gliders (Petaurus breviceps; 5 females and 1 male) in a retrospective review of 18 autopsied animals. Clinical signs for 3 of the sugar gliders included lethargy, tachypnea, and dyspnea....
    • Relationships between glucocorticoids and infection with Batrachochytrium dendrobatidis in three amphibian species

      Hammond, Talisin T.; Blackwood, Paradyse E.; Shablin, Samantha A.; Richards-Zawacki, Corinne L. (2020)
      It is often hypothesized that organisms exposed to environmental change may experience physiological stress, which could reduce individual quality and make them more susceptible to disease. Amphibians are amongst the most threatened taxa, particularly in the context of disease, but relatively few studies explore links between stress and disease in amphibian species....