• A reservoir species for the emerging amphibian pathogen Batrachochytrium dendrobatidis thrives in a landscape decimated by disease.

      Reeder, N.M.M.; Pessier, Allan P.; Vredenburg, V.T. (2012)
      Chytridiomycosis, a disease caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is driving amphibian declines and extinctions in protected areas globally. The introduction of invasive reservoir species has been implicated in the spread of Bd but does not explain the appearance of the pathogen in remote protected areas. In the high elevation (>1500 m) Sierra Nevada of California, the native Pacific chorus frog, Pseudacris regilla, appears unaffected by chytridiomycosis while sympatric species experience catastrophic declines. We investigated whether P. regilla is a reservoir of Bd by comparing habitat occupancy before and after a major Bd outbreak and measuring infection in P. regilla in the field, monitoring susceptibility of P. regilla to Bd in the laboratory, examining tissues with histology to determine patterns of infection, and using an innovative soak technique to determine individual output of Bd zoospores in water. Pseudacris regilla persists at 100% of sites where a sympatric species has been extirpated from 72% in synchrony with a wave of Bd. In the laboratory, P. regilla carried loads of Bd as much as an order of magnitude higher than loads found lethal to sympatric species. Histology shows heavy Bd infection in patchy areas next to normal skin, a possible mechanism for tolerance. The soak technique was 77.8% effective at detecting Bd in water and showed an average output of 68 zoospores per minute per individual. The results of this study suggest P. regilla should act as a Bd reservoir and provide evidence of a tolerance mechanism in a reservoir species....
    • AMPHIBIAN DISEASES-Batrachochytrium dendrobatidis in Adult Notophthalmus viridescens in North-Central Alabama, USA

      Bakkegard, K. A.; Pessier, Allan P.; (2010)
      ...We report on a haphazard collection of dead adult Notophthalmus viridescens discovered during a field zoology class trip conducted by KAB in Birmingham, Alabama....
    • An enigmatic mortality event in the only population of the Critically Endangered Cameroonian frog Xenopus longipes

      Blackburn, David C.; Evans, Ben J.; Pessier, Allan P.; Vredenburg, Vance T.; (2010)
      Contemporary global declines and mortality events in amphibian populations have been often attributed to infectious disease and climate change, separately and in combination. We report on an enigmatic mortality event in the only known population of the Critically Endangered frog species Xenopus longipes....
    • Batrachochytrium dendrobatidis in Adult Notophthalmus viridescens in North-Central Alabama, USA

      Bakkegard, Kristin; Pessier, Allan P.; (2010)
      ...We report on a haphazard collection of dead adult Notophthalmus viridescens discovered during a field zoology class trip conducted by KAB in Birmingham, Alabama....
    • Climate suitability as a predictor of conservation translocation failure

      Bellis, Joe; Bourke, David; Maschinski, Joyce; Heineman, Katherine D.; Dalrymple, Sarah (2020)
      …We used species distribution models (SDMs) to predict the climate suitability of 102 release sites for amphibians, reptiles and terrestrial insects and compared suitability predictions between successful and failed attempts. We then quantified the importance of climate suitability relative to five other variables frequently considered in the literature to be important determinants of translocation success: number of release years, number of individuals released, life stage released, origin of the source population and position of the release site relative to the species’ range….
    • Clinical trials with itraconazole as a treatment for chytrid fungal infections in amphibians

      Brannelly, L.A.; Richards-Zawacki, C.L.; Pessier, Allan P. (2012)
      Due in large part to recent global declines and extinctions, amphibians are the most threatened vertebrate group. Captive assurance colonies may be the only lifeline for some rapidly disappearing species. Maintaining these colonies free of disease represents a challenge to effective amphibian conservation. The fungal disease chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), is one of the major contributors to global amphibian declines and also poses a serious threat to captive assurance colonies. Many treatment options for Bd infection have not been experimentally tested and the commonly administered dosages of some drugs are known to have negative side effects, highlighting a need for clinical trials. The objective of this study was to clinically test the drug itraconazole as a method for curing Bd infection. We bathed Bd-positive juveniles of 2 anuran amphibian species, Litoria caerulea and Incilius nebulifer, in aqueous itraconazole, varying the concentration and duration of treatment, to find the combination that caused the fewest side effects while also reliably ridding animals of Bd. Our results suggest that a bath in 0.0025% itraconazole for 5 min d?1 for 6 d reliably cures Bd infection and causes fewer side effects than the longer treatment times and higher concentrations of this drug that are commonly administered.
    • Conservation of amphibians and reptiles in the British Virgin Islands: status and patterns

      Perry, G.; Gerber, Glenn P.; Hailey, A.; Wilson, B.S.; Horrocks, J. (Brill Academic PublishersLeiden, The Netherlands, 2011)
      ...Invasive species are still arriving, establishing, and spreading. Thus, although the short-term conservation status of the BVI herpetofauna appears unlikely to change, we are more concerned about the mid-term outlook. We recommend some specific remedies intended to offset these pressures and provide long-term protection to the biota of the BVI
    • Diagnosis and control of amphibian chytridiomycosis

      Pessier, Allan P.; Miller, R. Eric; Fowler, Murray E. (Elsevier SaundersSt. Louis, 2012)
      Chytridiomycosis is an emerging infectious disease associated with global amphibian population dec- lines. The causative agent, Batrachochytrium dendrobatidis (Bd), is a chytrid fungus with a broad host range documented to infect the skin of over 300 different frog and salamander species to date (www.spatialepidemiology.net/bd-maps)....
    • Survey for the pathogenic chytrid fungus Batrachochytrium dendrobatidis in Southwestern North Carolina salamander populations

      Keitzer, S. Conor; Goforth, Reuben; Pessier, Allan P.; Johnson, April J. (2011)
      Batrachochytrium dendrobatidis is a fungal pathogen responsible for a potentially fatal disease of amphibians. We conducted a survey for B. dendrobatidis in the Appalachian Mountains of southwestern North Carolina, USA, from 10 June to 23 July 23 2009....
    • Treatment of chytridiomycosis requires urgent clinical trials

      Berger, L; Speare, R; Pessier, Allan A.; Voyles, J; Skerratt, L.F.; (2010)
      Effective and safe treatments of amphibian chytridiomycosis caused by Batrachochytrium dendrobatidis (Bd), are needed to prevent mortality in captive programs, reduce the risk of disease spread, and better manage the disease in threatened wild populations. Bd is susceptible to a range of antifungal agents and low levels of heat (>30°C) when tested in vitro, but there are few proven methods for clearing adult amphibians of Bd, and acute drug toxicity is a problem for tadpoles and juveniles....