• Amphibian chytridiomycosis

      Pessier, Allan P.; Divers, S.; Mader, D. (ElsevierSt. Louis, 2014)
    • Drought reduces chytrid fungus (batrachochytrium dendrobatidis) infection intensity and mortality but not prevalence in adult crawfish frogs (lithobates areolatus)

      Terrell, Vanessa C. K.; Engbrecht, Nathan J.; Pessier, Allan P.; Lannoo, Michael J. (2014)
      To fully understand the impacts of the chytrid fungus Batrachochytrium dendrobatidis (Bd) on amphibians it is necessary to examine the interactions between populations and their environment. Ecologic variables can exacerbate or ameliorate Bd prevalence and infection intensity, factors that are positively related when Bd is acting on naive amphibian populations as an epidemic disease….
    • 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.
    • Emerging trends for biobanking amphibian genetic resources: The hope, reality and challenges for the next decade

      Kouba, Andrew J.; Lloyd, Rhiannon E.; Houck, Marlys L.; Silla, Aimee J.; Calatayud, Natalie E.; Trudeau, Vance L.; Clulow, John; Molinia, Frank; Langhorne, Cecilia; Vance, Carrie; et al. (2013)
      …Although many institutions have responded by establishing captive assurance colonies for several critically endangered amphibians, the resources provided by these conservation organizations will not be enough to save all species ‘at risk’ without a multi-pronged approach… Several international workshops on amphibian gene banking and assisted reproductive technologies have been held between 2010 and 2012, bringing together leading experts in the fields of amphibian ecology, physiology, and cryobiology to synthesize emerging trends for biobanking amphibian genetic resources, provide opportunities for collaboration, and discuss future research directions.…
    • External reinfection of a fungal pathogen does not contribute to pathogen growth

      DiRenzo, Graziella V.; Tunstall, Tate S.; Ibáñez, Roberto; deVries, Maya S.; Longo, Ana V.; Zamudio, Kelly R.; Lips, Karen R. (2018)
      Chytridiomycosis is an emerging infectious disease of amphibians caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), which has led to devastating declines in amphibian populations worldwide. Current theory predicts that Bd infections are maintained through both reproduction on the host’s skin and reinfection from sources outside of the host....
    • 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.
    • 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.” ....
    • Integrating current methods for the preservation of amphibian genetic resources and viable tissues to achieve best practices for species conservation

      Zimkus, Breda M; Hassapakis, Craig L; Houck, Marlys L. (2018)
      Global amphibian declines associated with anthropogenic causes, climate change, and amphibianspecific infectious diseases (e.g., chytridiomycosis) have highlighted the importance of biobanking amphibian genetic material. Genetic resource collections were the first to centralize the long-term storage of samples for use in basic science, including disciplines such as molecular evolution, molecular genetics, phylogenetics, and systematics. Biobanks associated with conservation breeding programs put a special emphasis on the cryopreservation of viable cells. These cell lines have a broader application, including the potential for genetic rescue and use in species propagation for population enhancement, such as captive breeding and reintroduction programs. We provide an overview of the most commonly used methods for the preservation of genetic resources, identify ways to standardize collection processes across biobanks, and provide decision trees to assist researchers in maximizing the potential use of their samples for both scientific research and the practice of species conservation. We hope that the collection and deposition of tissues preserved using methods that enable eventual cell line establishment will become routine practice among researchers, particularly herpetologists working in the field. While many major museums do not yet cryopreserve reproductive cells or cell lines, they contain the infrastructure and staff to maintain these collections if protocols and procedures are adapted. Collaboration between organizations can play an important future role in the conservation of amphibians, especially biobanks associated with research institutions and those pioneering techniques used in breeding programs.
    • Isolation of a Bohle-like iridovirus from boreal toads housed within a cosmopolitan aquarium collection

      Cheng, Kwang; Jones, Megan E. B.; Jancovich, James K.; Burchell, Jennifer; Schrenzel, Mark D.; Reavill, Drury R.; Imai, Denise M.; Urban, Abby; Kirkendall, Maryanne; Woods, Leslie W.; et al. (2014)
      A captive ‘survival assurance’ population of 56 endangered boreal toads Anaxyrus boreas boreas, housed within a cosmopolitan collection of amphibians originating from Southeast Asia and other locations, experienced high mortality (91%) in April to July 2010. Histological examination demonstrated lesions consistent with ranaviral disease, including multicentric necrosis of skin, kidney, liver, spleen, and hematopoietic tissue, vasculitis, and myriad basophilic intracytoplasmic inclusion bodies…. This finding has implications for the management of amphibians destined for use in reintroduction programs, as their release may inadvertently lead to viral dissemination.
    • 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….
    • Moving towards greater success in translocations: recent advances from the herpetofauna

      Germano, Jennifer M.; Ewen, J. G.; Mushinsky, H.; McCoy, E.; Ortiz-Catedral, L. (2014)
      ...While the idea of moving an animal may seem simple at first glance, the reality is that translocations are inherently complex. In order to improve our rates of success, this complexity must be considered....
    • Nutrition and health in amphibian husbandry: Ex situ amphibian health and nutrition

      Ferrie, Gina M.; Alford, Vance C.; Atkinson, Jim; Baitchman, Eric; Barber, Diane; Blaner, William S.; Crawshaw, Graham; Daneault, Andy; Dierenfeld, Ellen; Finke, Mark; et al. (2014)
      Amphibian biology is intricate, and there are many inter‐related factors that need to be understood before establishing successful Conservation Breeding Programs (CBPs). Nutritional needs of amphibians are highly integrated with disease and their husbandry needs, and the diversity of developmental stages, natural habitats, and feeding strategies result in many different recommendations for proper care and feeding….
    • 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….
    • Ovarian control and monitoring in amphibians

      Calatayud, Natalie E.; Stoops, M.; Durrant, Barbara S. (2018)
      Amphibian evolution spans over 350 million years ago, consequently this taxonomic group displays a wide, complex array of physiological adaptations and their diverse modes of reproduction are a prime example. Reproduction can be affected by taxonomy, geographic and altitudinal distribution, and environmental factors....
    • Pathogenesis, diagnosis, and treatment of amphibian chytridiomycosis

      Baitchman, Eric J.; Pessier, Allan P. (2013)
      Amphibian chytridiomycosis, caused by the chytridiomycete fungus, Batrachochytrium dendrobatidis (Bd), is responsible for a global pandemic that has dramatically reduced global amphibian populations and diversity. Species declines, extirpations, and extinctions attributed to chytridiomycosis have occurred in Australia, Europe, Latin America, and the United States….
    • 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.
    • Rapid response to evaluate the presence of amphibian chytrid fungus (Batrachochytrium dendrobatidis) and ranavirus in wild amphibian populations in Madagascar

      Kolby, Jonathan E.; Smith, Kristine M.; Ramirez, Sara D.; Rabemananjara, Falitiana; Pessier, Allan P.; Brunner, Jesse L.; Goldberg, Caren S.; Berger, Lee; Skerratt, Lee F. (2015)
      We performed a rapid response investigation to evaluate the presence and distribution of amphibian pathogens in Madagascar following our identification of amphibian chytrid fungus (Batrachochytrium dendrobatidis, Bd) and ranavirus in commercially exported amphibians. This targeted risk-based field surveillance program was conducted from February to April 2014 encompassing 12 regions and 47 survey sites. We simultaneously collected amphibian and environmental samples to increase survey sensitivity and performed sampling both in wilderness areas and commercial amphibian trade facilities. Bd was not detected in any of 508 amphibian skin swabs or 68 water filter samples, suggesting pathogen prevalence was below 0.8%, with 95% confidence during our visit. Ranavirus was detected in 5 of 97 amphibians, including one adult Mantidactylus cowanii and three unidentified larvae from Ranomafana National Park, and one adult Mantidactylus mocquardi from Ankaratra. Ranavirus was also detected in water samples collected from two commercial amphibian export facilities. We also provide the first report of an amphibian mass-mortality event observed in wild amphibians in Madagascar. Although neither Bd nor ranavirus appeared widespread in Madagascar during this investigation, additional health surveys are required to disentangle potential seasonal variations in pathogen abundance and detectability from actual changes in pathogen distribution and rates of spread. Accordingly, our results should be conservatively interpreted until a comparable survey effort during winter months has been performed. It is imperative that biosecurity practices be immediately adopted to limit the unintentional increased spread of disease through the movement of contaminated equipment or direct disposal of contaminated material from wildlife trade facilities. The presence of potentially introduced strains of ranaviruses suggests that Madagascar's reptile species might also be threatened by disease. Standardized population monitoring of key amphibian and reptile species should be established with urgency to enable early detection of potential impacts of disease emergence in this global biodiversity hotspot.
    • 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....
    • Reproductive techniques for ovarian monitoring and control in amphibians

      Calatayud, Natalie E.; Chai, Norin; Gardner, Nicole R.; Curtis, Michelle J.; Stoops, Monica A. (2019)
      Ovarian control and monitoring in amphibians require a multi-faceted approach. There are several applications that can successfully induce reproductive behaviors and the acquisition of gametes and embryos for physiological or molecular research. Amphibians contribute to one-quarter to one-third of vertebrate research, and of interest in this context is their contribution to the scientific community's knowledge of reproductive processes and embryological development. However, most of this knowledge is derived from a small number of species. In recent times, the decimation of amphibians across the globe has required increasing intervention by conservationists. The captive recovery and assurance colonies that continue to emerge in response to the extinction risk make existing research and clinical applications invaluable to the survival and reproduction of amphibians held under human care. The success of any captive population is founded on its health and reproduction and the ability to develop viable offspring that carry forward the most diverse genetic representation of their species. For researchers and veterinarians, the ability to monitor and control ovarian development and health is, therefore, imperative. The focus of this article is to highlight the different assisted reproductive techniques that can be used to monitor and, where appropriate or necessary, control ovarian function in amphibians. Ideally, any reproductive and health issues should be reduced through proper captive husbandry, but, as with any animal, issues of health and reproductive pathologies are inevitable. Non-invasive techniques include behavioral assessments, visual inspection and palpation and morphometric measurements for the calculation of body condition indices and ultrasound. Invasive techniques include hormonal injections, blood sampling, and surgery. Ovarian control can be exercised in a number of ways depending on the application required and species of interest.
    • Short tongue syndrome and hypovitaminosis A

      Pessier, Allan P.; Divers, S.; Mader, D. (ElsevierSt. Louis, 2014)