• 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.
    • Co-infection by alveolate parasites and frog virus 3-like ranavirus during an amphibian larval mortality event in Florida, USA

      Landsberg, J.H.; Kiryu, Y.; Tabuchi, M.; Preston, Asa; Pessier, Allan P. (2013)
      A multispecies amphibian larval mortality event, primarily affecting American bullfrogs Lithobates catesbeianus, was investigated during April 2011 at the Mike Roess Gold Head Branch State Park, Clay County, Florida, USA. Freshly dead and moribund tadpoles had hemorrhagic lesions around the vent and on the ventral body surface, with some exhibiting a swollen abdomen. Bullfrogs (100%), southern leopard frogs L. sphenocephalus (33.3%), and gopher frogs L. capito (100%) were infected by alveolate parasites. The intensity of infection in bullfrog livers was high. Tadpoles were evaluated for frog virus 3 (FV3) by histology and PCR. For those southern leopard frog tadpoles (n = 2) whose livers had not been obscured by alveolate spore infection, neither a pathologic response nor intracytoplasmic inclusions typically associated with clinical infections of FV3-like ranavirus were noted. Sequencing of a portion (496 bp) of the viral major capsid protein gene confirmed FV3-like virus in bullfrogs (n = 1, plus n = 6 pooled) and southern leopard frogs (n = 1, plus n = 4 pooled). In July 2011, young-of-the-year bullfrog tadpoles (n = 7) were negative for alveolate parasites, but 1 gopher frog tadpole was positive. To our knowledge, this is the first confirmed mortality event for amphibians in Florida associated with FV3-like virus, but the extent to which the virus played a primary role is uncertain. Larval mortality was most likely caused by a combination of alveolate parasite infections, FV3-like ranavirus, and undetermined etiological factors.
    • Differential success in obtaining gametes between male and female Australian temperate frogs by hormonal induction: A review

      Clulow, John; Pomering, Melissa; Herbert, Danielle; Upton, Rose; Calatayud, Natalie E.; Clulow, Simon; Mahony, Michael J.; Trudeau, Vance L. (2018)
      Most Australian frogs fall into two deeply split lineages, conveniently referred to as ground frogs (Myobatrachidae and Limnodynastidae) and tree frogs (Pelodryadidae). Species of both lineages are endangered because of the global chytrid pandemic, and there is increasing interest and research on the endocrine manipulation of reproduction to support the use of assisted reproductive technologies in conservation....
    • Efficacy of treatment and long-term follow-up of Batrachochytrium dendrobatidis PCR-positive anurans following itraconazole bath treatment

      Georoff, Timothy A.; Moore, Robert P.; Rodriguez, Carlos; Pessier, Allan P.; Newton, Alisa L.; McAloose, Denise; Calle, Paul P. (2013)
      All anuran specimens in the Wildlife Conservation Society's collections testing positive for Batrachochytrium dendrobatidis (Bd) were treated with itraconazole and then studied after treatment to assess the long-term effects of itraconazole and the drug's effectiveness in eliminating Bd carriers. Twenty-four individuals and eight colonies of 11 different species (75 total specimens) tested positive for Bd via polymerase chain reaction (PCR) on multicollection survey. All positive individuals and colonies were treated with a 0.01% itraconazole bath solution and retested for Bd via one of two PCR methodologies within 14 days of treatment completion, and all were negative for Bd. A total of 64 animals received secondary follow-up PCR testing at the time of death, 6–8 mo, or 12–15 mo post-treatment. Fourteen animals (14/64, 21.9%) were PCR positive for Bd on second follow-up. The highest percentage positive at second recheck were green-and-black poison dart frogs (Dendrobates auratus; 5/5 specimens, 100%), followed by red-eyed tree frogs (Agalychnis callidryas; 4/11, 36.4%), grey tree frogs (Hyla versicolor; 1/3, 33.3%), and green tree frogs (Hyla cinera; 3/11, 27.3%). Re-testing by PCR performed on 26/28 individuals that died during the study indicated 11/26 (42.3%) were positive (all via DNA extracted from formalin-fixed paraffin-embedded skin sections). However, there was no histologic evidence of chytridiomycosis in any of 27/28 individuals. The small number of deceased animals and effects of postmortem autolysis limited the ability to determine statistical trends in the pathology data, but none of the necropsied specimens showed evidence of itraconazole toxicity. Problems with itraconazole may be species dependent, and this report expands the list of species that can tolerate treatment. Although itraconazole is effective for clearance of most individuals infected with Bd, results of the study suggest that repeat itraconazole treatment and follow-up diagnostics may be required to ensure that subclinical infections are eliminated in amphibian collections.
    • 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....
    • Population genetic analysis of the recently rediscovered Hula painted frog ( Latonia nigriventer ) reveals high genetic diversity and low inbreeding

      Perl, R. G. Bina; Geffen, Eli; Malka, Yoram; Barocas, Adi; Renan, Sharon; Vences, Miguel; Gafny, Sarig (2018)
      After its recent rediscovery, the Hula painted frog (Latonia nigriventer) has remained one of the world’s rarest and least understood amphibian species. Together with its apparently low dispersal capability and highly disturbed niche, the low abundance of this living fossil calls for urgent conservation measures. We used 18 newly developed microsatellite loci and four different models to calculate the effective population size (Ne) of a total of 125 Hula painted frog individuals sampled at a single location. We compare the Ne estimates to the estimates of potentially reproducing adults in this population (Nad) determined through a capture-recapture study on 118 adult Hula painted frogs captured at the same site. Surprisingly, our data suggests that, despite Nad estimates of only ~234–244 and Ne estimates of ~16.6–35.8, the species appears to maintain a very high genetic diversity (HO = 0.771) and low inbreeding coefficient (FIS = −0.018). This puzzling outcome could perhaps be explained by the hypotheses of either genetic rescue from one or more unknown Hula painted frog populations nearby or by recent admixture of genetically divergent subpopulations. Independent of which scenario is correct, the original locations of these populations still remain to be determined.