• 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....
    • Amdoparvovirus Infection in Red Pandas (Ailurus fulgens)

      Alex, Charles E.; Kubiski, Steven V.; Li, Linlin; Sadeghi, Mohammadreza; Wack, Raymund F.; McCarthy, Megan A.; Pesavento, Joseph B.; Delwart, Eric; Pesavento, Patricia A. (2018)
      Aleutian mink disease virus is the type species in the genus Amdoparvovirus, and in mink and other Mustelidae can cause either subclinical disease or fatal chronic immune stimulation and immune complex disease. The authors describe a novel amdoparvovirus in the endangered red panda (Ailurus fulgens), discovered using viral metagenomics....
    • 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.
    • Comparative pathology of ranaviruses and diagnostic techniques

      Miller, D.L.; Pessier, Allan P.; Hick, P.; Whittington, R.J.; Gray M.; Chinchar V. (SpringerNew York, 2015)
      Recognizing the pathological changes caused by ranaviruses, understanding how to properly collect test samples, and knowing what diagnostic tools to choose are key to detecting ranaviruses and in determining whether they are a factor in morbidity and mortality events. Whether infection occurs in fish, reptiles, or amphibians, clinical disease is typically acute and can affect a high proportion of the population. Among ectothermic vertebrates, affected individuals can present with hemorrhages, edema, and necrosis. Generally, microscopic examination reveals intracytoplasmic inclusion bodies and necrosis of hematopoietic tissues, vascular endothelium, and epithelial cells. Ultimately, the type and severity of the lesions that develop vary depending upon the host species, type of ranavirus, or environmental factors. Our ability to identify lesions caused by ranaviruses is improving because of the knowledge gained from laboratory experiments and the improvement of existing, or development of new diagnostic tests. There is no single Gold Standard test for ranavirus detection, rather the diagnostic test chosen depends on the question asked. For example, a surveillance study may use quantitative real-time PCR (qPCR) to detect ranaviruses, but an investigation of a mortality event may use virus isolation, qPCR, histopathology, electron microscopy, and bioassay. To date, a treatment for ranavirus infections has not been found; however, vaccine development against iridoviruses is showing promise for both DNA and live vaccines within the aquaculture industry.
    • Development of a case definition for clinical feline herpesvirus infection in cheetahs (acinonyx jubatus) housed in zoos

      Witte, Carmel L.; Lamberski, Nadine; Rideout, Bruce; Fields, Victoria; Teare, Cyd Shields; Barrie, Michael; Haefele, Holly; Junge, Randall; Murray, Suzan; Hungerford, Laura L. (2013)
      The identification of feline herpesvirus (FHV) infected cheetahs (Acinonyx jubatus) and characterization of shedding episodes is difficult due to nonspecific clinical signs and limitations of diagnostic tests. The goals of this study were to develop a case definition for clinical FHV and describe the distribution of signs. Medical records from six different zoologic institutions were reviewed to identify cheetahs with diagnostic test results confirming FHV….
    • Duration of maternal antibodies against canine distemper virus and hendra virus in pteropid bats

      Epstein, Jonathan H.; Baker, Michelle L.; Zambrana-Torrelio, Carlos; Middleton, Deborah; Barr, Jennifer A.; DuBovi, Edward; Boyd, Victoria; Pope, Brian; Todd, Shawn; Crameri, Gary; et al. (2013)
      Old World frugivorous bats have been identified as natural hosts for emerging zoonotic viruses of significant public health concern, including henipaviruses (Nipah and Hendra virus), Ebola virus, and Marburg virus. Epidemiological studies of these viruses in bats often utilize serology to describe viral dynamics, with particular attention paid to juveniles, whose birth increases the overall susceptibility of the population to a viral outbreak once maternal immunity wanes. However, little is understood about bat immunology, including the duration of maternal antibodies in neonates. Understanding duration of maternally derived immunity is critical for characterizing viral dynamics in bat populations, which may help assess the risk of spillover to humans. We conducted two separate studies of pregnant Pteropus bat species and their offspring to measure the half-life and duration of antibodies to 1) canine distemper virus antigen in vaccinated captive Pteropus hypomelanus; and 2) Hendra virus in wild-caught, naturally infected Pteropus alecto. Both of these pteropid bat species are known reservoirs for henipaviruses. We found that in both species, antibodies were transferred from dam to pup. In P. hypomelanus pups, titers against CDV waned over a mean period of 228.6 days (95% CI: 185.4–271.8) and had a mean terminal phase half-life of 96.0 days (CI 95%: 30.7–299.7). In P. alecto pups, antibodies waned over 255.13 days (95% CI: 221.0–289.3) and had a mean terminal phase half-life of 52.24 days (CI 95%: 33.76–80.83). Each species showed a duration of transferred maternal immunity of between 7.5 and 8.5 months, which was longer than has been previously estimated. These data will allow for more accurate interpretation of age-related Henipavirus serological data collected from wild pteropid bats.
    • Epidemiology of clinical feline herpesvirus infection in zoo-housed cheetahs (Acinonyx jubatus)

      Witte, Carmel L.; Lamberski, Nadine; Rideout, Bruce; Vaida, Florin; Citino, Scott B.; Barrie, Michael T.; Haefele, Holly J.; Junge, Randall E.; Murray, Suzan; Hungerford, Laura L. (2017)
      OBJECTIVE To determine the incidence of and risk factors for clinical feline herpesvirus (FHV) infection in zoo-housed cheetahs and determine whether dam infection was associated with offspring infection. DESIGN Retrospective cohort study....
    • 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.
    • Rigorous wildlife disease surveillance

      Watsa, Mrinalini; Wildlife Disease Surveillance Focus Group; Erkenswick, G.; Prost, S.; Davis, Elizabeth Oneita; Moore, Caroline; Kubiski, Steven V.; Witte, Carmel L.; Ogden, R.; Meredith, A.; et al. (2020)
      Evidence suggests that zoonotic (animal origin) coronaviruses have caused three recent emerging infectious disease (EID) outbreaks: severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), and the current coronavirus disease 2019 (COVID-19) pandemic. In the search for an intermediate host for SARS coronavirus 2 (SARS-CoV-2, which causes COVID-19), studies have identified SARS-CoV-2–like strains in bats (1) and pangolins (2), but these do not contain the same polybasic cleavage site that is present in SARS-CoV-2 (3). It is unknown what the intermediate host for this spillover event was because to date there are no international or national conventions on pathogen screening associated with animals, animal products, or their movements, and capacity for EID diagnostics is limited along much of the human-wildlife interface....
    • The first reptilian circovirus identified infects gut and liver tissues of black-headed pythons

      Altan, Eda; Kubiski, Steven V.; Burchell, Jennifer; Bicknese, Elizabeth; Deng, Xutao; Delwart, Eric (2019)
      Viral metagenomic analysis of the liver of a black headed python (Aspidites melanocephalus) euthanized for a proliferative spinal lesion of unknown etiology yielded the first characterized genome of a reptile-infecting circovirus (black-headed python circovirus or BhPyCV). BhPyCV-specific in situ hybridization (ISH) showed that viral nucleic acids were strongly expressed in the intestinal lining and mucosa and multifocally in the liver. To investigate the presence of this virus in other snakes and its possible pathogenicity, 17 snakes in the python family with spinal disease were screened with ISH yielding a second BhP positive in intestinal tissue, and a Boelen’s python (Morelia boeleni) positive in the liver. BhPyCV specific PCR was used to screen available frozen tissues from 13 of these pythons, four additional deceased pythons with and without spinal disease, and fecal samples from 37 live snakes of multiple species with unknown disease status. PCR detected multiple positive tissues in both of the ISH positive BhP and in the feces of another two live BhP and two live annulated tree boas (Corallus annulatus). Preliminary analysis indicates this circovirus can infect BhPs where it was found in 4/5 BhPs tested (2/2 with spinal disease, 2/3 live with unknown status), Boelen’s python (1/2 with spinal disease), and annulated tree boa (2/6 live with unknown status) but was not detected in other python species with the same spinal lesions. This circovirus’ causal or contributory role in spinal disease remains speculative and not well supported by these initial data.