• 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....
    • Comparison of beak and feather disease virus prevalence and immunity-associated genetic diversity over time in an island population of red-crowned parakeets

      Knafler, Gabrielle J.; Ortiz-Catedral, Luis; Jackson, Bethany; Varsani, Arvind; Grueber, Catherine E.; Robertson, Bruce C.; Jamieson, Ian G. (2016)
      …Beak and feather disease virus (BFDV) was detected for the first time in an island population of red-crowned parakeets (Cyanoramphus novaezelandiae) in 2008 on Little Barrier Island (Hauturu-o-Toi) of New Zealand. By 2013, the prevalence of the viral infection had significantly decreased within the population….
    • Depositional diseases

      Graham, E.A.; Burns, Rachel E.; Ossiboff, R. J.; Garner, Michael M.; Jacobson, Elliott R. (CRC Press, 2021)
      This book accompanies Infectious Diseases and Pathology of Reptiles, Second Edition to cover noninfectious diseases of reptiles, meeting the need for a similar, authoritative single-source reference. The volume features color photos of normal anatomy and histology, as well as gross, light, and electron microscopic imagery of diseases. Subjects range from neoplasia, nutrition, and metabolic disease, and deposition disorders to developmental anomalies, trauma, and physical diseases, and the unique contribution of paleopathology and diseases of bone. Each chapter is supported by numerous figures, many of which are unique and cannot be found in the published literature. Readers will note that some of the chapters are based on organ system, a trend that will continue into the next edition to encompass all of the basic organ systems. This book holds the most information ever accrued into one publication on noninfectious diseases and pathology of this class of animals, providing information on every aspect of the anatomy, pathophysiology, and differential diagnosis. With up-to-the-minute data, a never-before-seen collection of images, and a stellar panel of contributors, Noninfectious Diseases and Pathology of Reptiles is the definitive resource for veterinarians, biologists, and researchers involved in the study of reptile diseases.
    • Disseminated coccidoidomycosis in a koala (Phascolarctos cinereus)

      Burgdorf-Moisuk, Anne; Stalis, Ilse H.; Pye, Geoffrey W. (2012)
      A16-yr-old male koala (Phascolarctos cinereus) presented for nonspecific signs of illness and weight loss. Despite 2 mo of diagnostics and supportive care, the koala's health declined and euthanasia was elected....
    • Human and great ape red blood cells differ in plasmalogen levels and composition

      Moser, A.B.; Steinberg, S.J.; Watkins, P.A.; Moser, H.W.; Ramaswamy, K.; Siegmund, K.D.; Lee, D.R.; Ely, J.J.; Ryder, Oliver A.; Hacia, J.G. (2011)
      Plasmalogens are ether phospholipids required for normal mammalian developmental, physiological, and cognitive functions. They have been proposed to act as membrane antioxidants and reservoirs of polyunsaturated fatty acids as well as influence intracellular signaling and membrane dynamics. Plasmalogens are particularly enriched in cells and tissues of the human nervous, immune, and cardiovascular systems. Humans with severely reduced plasmalogen levels have reduced life spans, abnormal neurological development, skeletal dysplasia, impaired respiration, and cataracts. Plasmalogen deficiency is also found in the brain tissue of individuals with Alzheimer disease.
    • Investigating embryo deaths and hatching failure

      Rideout, Bruce (2012)
      Artificial incubation and hand-rearing allow aviculturists to greatly increase the reproductive potential of breeding populations. When one clutch is pulled for artificial incubation, a second clutch will typically be laid, which can then be parent-reared or also pulled for artificial incubation, thereby doubling or tripling reproductive output....
    • Koala retrovirus diversity, transmissibility, and disease associations

      Zheng, HaoQiang; Pan, Yi; Tang, Shaohua; Pye, Geoffrey W.; Stadler, Cynthia K; Vogelnest, Larry; Herrin, Kimberly Vinette; Rideout, Bruce; Switzer, William M. (2020)
      Background Koalas are infected with the koala retrovirus (KoRV) that exists as exogenous or endogenous viruses. KoRV is genetically diverse with co-infection with up to ten envelope subtypes (A-J) possible; KoRV-A is the prototype endogenous form. KoRV-B, first found in a small number of koalas with an increased leukemia prevalence at one US zoo, has been associated with other cancers and increased chlamydial disease. To better understand the molecular epidemiology of KoRV variants and the effect of increased viral loads (VLs) on transmissibility and pathogenicity we developed subtype-specific quantitative PCR (qPCR) assays and tested blood and tissue samples from koalas at US zoos (n=78), two Australian zoos (n=27) and wild-caught (n=21) in Australia. We analyzed PCR results with available clinical, demographic, and pedigree data. Results All koalas were KoRV-A-infected. A small number of koalas (10.3%) at one US zoo were also infected with non-A subtypes, while a higher non-A subtype prevalence (59.3%) was found in koalas at Australian zoos. Wild koalas from one location were only infected with KoRV-A. We observed a significant association of infection and plasma VLs of non-A subtypes in koalas that died of leukemia/lymphoma and other neoplasias and report cancer diagnoses in KoRV-A-positive animals. Infection and VLs of non-A subtypes was not associated with age or sex. Transmission of non-A subtypes occurred from dam-to-offspring and likely following adult-to-adult contact, but associations with contact type were not evaluated. Brief antiretroviral treatment of one leukemic koala infected with high plasma levels of KoRV-A, -B, and -F did not affect VL or disease progression. Conclusions Our results show a significant association of non-A KoRV infection and plasma VLs with leukemia and other
    • Metabolic bone disease in juvenile koalas (phascolartcos cinereus)

      Pye, Geoffrey W.; Gait, Sarah Catherine; Mulot, Baptiste; de Asua, Maria Delclaux Real; Martinez-Nevado, Eva; Bonar, Christopher J.; Baines, Stephen J.; Baines, Elizabeth A. (2013)
      Due to climate restrictions in parts of North America and Europe, koalas (Phascolarctos cinereus) are housed indoors. Koala young (joeys) raised indoors are susceptible to the development of metabolic bone disease (MBD) due to a lack of exposure to natural ultraviolet light to themselves and their female paren....
    • Patterns of mortality in free-ranging California condors (Gymnogyps californianus)

      Rideout, Bruce; Stalis, Ilse H.; Papendick, Rebecca; Pessier, Alan P.; Puschner, B.; Finkelstien, M.E.; Smith, D.R.; Johnson, M.; Mace, Michael E.; Stroud, R.; et al. (2012)
      We document causes of death in free-ranging California Condors (Gymnogyps californianus) from the inception of the reintroduction program in 1992 through December 2009 to identify current and historic mortality factors that might interfere with establishment of self-sustaining populations in the wild. A total of 135 deaths occurred from October 1992 (the first post-release death) through December 2009, from a maximum population-at-risk of 352 birds, for a cumulative crude mortality rate of 38%. A definitive cause of death was determined for 76 of the 98 submitted cases, 70%(53/76) of which were attributed to anthropogenic causes. Trash ingestion was the most important mortality factor in nestlings (proportional mortality rate [PMR] 73%; 8/11), while lead toxicosis was the most important factor in juveniles (PMR 26%; 13/50) and adults (PMR 67%; 10/15). These results demonstrate that the leading causes of death at all California Condor release sites are anthropogenic. The mortality factors thought to be important in the decline of the historic California Condor population, particularly lead poisoning, remain the most important documented mortality factors today. Without effective mitigation, these factors can be expected to have the same effects on the sustainability of the wild populations as they have in the past.
    • Provision of ultraviolet basking lights to indoor housed tropical birds and their effect on suspected vitamin D3 deficiency

      Drake, Gabby Jeanne-Clare; Shea, Robyn L.; Fidgett, Andrea; Lopez, Javier; Christley, Robert M. (2017)
      Vitamin D deficiency (measured as 25(OH)D3) can occur if birds are fed a vitamin D deficient diet and do not have access to ultraviolet B light (UVB). This can result in eggs with deficient yolks and consequent metabolic bone disease (MBD) in chicks. In this study, hypovitaminosis D was suspected in 31 adult birds, from five orders, housed indoors long-term without prior access to UVB light. The study aimed to assess the effect of providing UVB basking lights on their vitamin D status and incidence of MBD in chicks. It also aimed to assess whether the birds would access the UVB provided. Breeding and pathology records were analysed, and birds were blood tested for 25(OH)D3 before, and 12 months after, being provided with access to UVB basking lights. The area of perching with UVB irradiance was filmed before and after the UVB basking lights were switched on. There was a significant increase in 25(OH)D3 after 12 months of UVB provision from a mean of 9.3 nmol/L to 14.2 nmol/L (p = 0.001, CI = 2.35 to 9.47). Annual incidence of metabolic bone disease in chicks dropped from an average of 14.4% over the three years prior to UVB provision to 2.8% in the two years afterwards, although this reduction was not statistically significant. Birds appeared to actively seek the basking spots and significantly increased the proportion of time spent in the area of UVB irradiance (p = 0.02). No correlation was found between the total amount, or change in time spent in the UVB area and the final, or change in individual birds circulating 25(OH)D3 levels. These results show that indoor housed birds will bask in UVB light if provided and this radiation can increase vitamin D levels of the birds, which may prevent MBD in their offspring.
    • Resolution of a localized granuloma caused by Mycobacterium avium-intracellulare complex on the cere of a Bruce's green pigeon (Treron waalia)

      Zikovitz, Andrea E.; Stalis, Ilse H.; Bicknese, Elizabeth; Rideout, Bruce; Pye, Geoffrey W. (2018)
      A 3-year-old female Bruce's green pigeon (Treron waalia) was presented with granulomatous inflammation of the cere and underlying tissues with osteomyelitis and bone proliferation of the dorsal premaxilla. Biopsy and culture revealed the presence of Mycobacterium avium-intracellulare complex, and multi-antimicrobial treatment was initiated with clarithromycin, ethambutol, rifabutin, and enrofloxacin....
    • 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....
    • Tumoral calcinosis form of hydroxyapatite deposition disease in related red-bellied short-necked turtles, Emydura subglobosa

      Burns, Rachel E.; Bicknese, Elizabeth; Westropp, J. L.; Shiraki, R.; Stalis, Ilse H. (2013)
      Ten of 12 red-bellied short-necked turtles from a single clutch presented at 9 months of age with multiple white to tan nodules on their feet. Histologically, the nodules were composed of large periarticular deposits of mineralized crystalline material that extended into the joint spaces of interphalangeal joints and was surrounded by granulomatous inflammation and fibrosis. Crystallographic analysis determined the material to be apatite (calcium phosphate hydroxide) consistent with the tumoral calcinosis form of hydroxyapatite deposition disease (HADD). HADD has previously been described in aquatic turtles and rarely lizards and must be differentiated from gout in reptiles. A cause for the tumoral calcinosis lesions in these turtles could not be determined; however, based on previous reports in this species, a species-specific predilection, in conjunction with unknown environmental factors, is suspected. The use of the terms HADD, pseudogout (calcium pyrophosphate crystal deposition disease), and calcinosiscircumscripta has been inconsistent, creating confusion in the literature.