Publications by authors named "Padraig Duignan"

46 Publications

A Comparison of Parapoxviruses in North American Pinnipeds.

Front Vet Sci 2021 17;8:653094. Epub 2021 May 17.

Department of Arctic and Marine Biology, UiT The Arctic University of Norway, Tromsø, Norway.

Parapoxviruses cause nodular lesions on the skin and mucosal membranes of pinnipeds and infections by these viruses have been documented worldwide. Seal parapoxvirus is currently classified as a tentative species of the genus. Tissue or swab samples were analyzed from 11 pinnipeds of different host species undergoing rehabilitation on the east and west coasts of the United States of America (USA) that were positive for parapoxvirus. The aim of the study was to compare parapoxvirus sequences of fragments of the and ( genes and to examine the evolutionary relationship between viruses detected in different pinniped species and at different locations with other members of the genus, such as Orf virus (ORFV), Bovine papular stomatitis virus (BPSV) and Pseudocowpox virus (PCPV). The sequence analysis showed that the parapoxvirus sequences from the pinnipeds differed significantly from those found in terrestrial hosts and that they formed a separate cluster within the genus. Our results suggest that transmission of the same parapoxvirus strain is possible between different species, including between members of different families (phocids and otariids). Animals belonging to the same species but living in distant geographic locations presented genetically distant parapoxviruses. The findings of this study demonstrate that sealpox lesions in pinnipeds of different species are caused by viruses that belong to the genus but have significant genetic differences compared to the established virus species in terrestrial hosts, thus strongly supporting the classification of pinniped parapoxvirus as a new species of the genus.
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http://dx.doi.org/10.3389/fvets.2021.653094DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8165162PMC
May 2021

Respiratory tract explant infection dynamics of influenza A virus in California sea lions, northern elephant seals, and rhesus macaques.

J Virol 2021 May 26:JVI0040321. Epub 2021 May 26.

University of California, Davis, School of Veterinary Medicine, Department of Pathology, Microbiology and Immunology, Davis, California.

To understand susceptibility of wild California sea lions and Northern elephant seals to influenza A virus (IAV), we developed an respiratory explant model and used it to compare infection kinetics for multiple IAV subtypes. We first established the approach using explants from colonized rhesus macaques, a model for human IAV. Trachea, bronchi, and lungs from 11 California sea lions, 2 Northern elephant seals and 10 rhesus macaques were inoculated within 24 hours post-mortem with 6 strains representing 4 IAV subtypes. Explants from the 3 species showed similar IAV infection kinetics with peak viral titers 48-72 hours post-inoculation that increased by 2-4 log plaque forming units (PFU)/explant relative to the inoculum. Immunohistochemistry localized IAV infection to apical epithelial cells. These results demonstrate that respiratory tissue explants from wild marine mammals support IAV infection. In the absence of the ability to perform experimental infections of marine mammals, this culture of respiratory tissues mirrors the environment and serves as a tool to study IAV susceptibility, host-range, and tissue tropism. Although influenza A virus can infect marine mammals, a dearth of marine mammal cell lines and ethical and logistical challenges prohibiting experimental infections of living marine mammals means that little is known about IAV infection kinetics in these species. We circumvented these limitations by adapting a respiratory tract explant model first to establish the approach with rhesus macaques and then for use with explants from wild marine mammals euthanized for non-respiratory medical conditions. We observed that multiple strains representing 4 IAV subtypes infected trachea, bronchi, and lungs of macaques and marine mammals with variable peak titers and kinetics. This model can define infection dynamics for IAV in marine mammals. Further, use of explants from animals euthanized for other reasons reduces use of animals in research.
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http://dx.doi.org/10.1128/JVI.00403-21DOI Listing
May 2021

CLASSIFICATION AND REGRESSION TREE ANALYSIS FOR PREDICTING PROGNOSIS IN WILDLIFE REHABILITATION: A CASE STUDY OF LEPTOSPIROSIS IN CALIFORNIA SEA LIONS ().

J Zoo Wildl Med 2021 Apr;52(1):38-48

Department of Ecology and Evolutionary Biology, University of California, Los Angeles, CA 90095, USA.

The spirochete bacterium serovar Pomona is enzootic to California sea lions (CSL; ) and causes periodic epizootics. Leptospirosis in CSL is associated with a high fatality rate in rehabilitation. Evidence-based tools for estimating prognosis and guiding early euthanasia of animals with a low probability of survival are critical to reducing the severity and duration of animal suffering. Classification and regression tree (CART) analysis of clinical data was used to predict survival outcomes of CSL with leptospirosis in rehabilitation. Classification tree outputs are binary decision trees that can be readily interpreted and applied by a clinician. Models were trained using data from cases treated from 2017 to 2018 at The Marine Mammal Center in Sausalito, CA, and tested against data from cases treated from 2010 to 2012. Two separate classification tree analyses were performed, one including and one excluding data from euthanized animals. When data from natural deaths and euthanasias were included in model-building, the best classification tree predicted outcomes correctly for 84.7% of cases based on four variables: appetite over the first 3 days in care, and blood urea nitrogen (BUN), creatinine, and sodium at admission. When only natural deaths were included, the best model predicted outcomes correctly for 87.6% of cases based on BUN and creatinine at admission. This study illustrates that CART analysis can be successfully applied to wildlife in rehabilitation to establish evidence-based euthanasia criteria with the goal of minimizing animal suffering. In the context of a large epizootic that challenges the limits of a facility's capacity for care, the models can assist in maximizing allocation of resources to those animals with the highest predicted probability of survival. This technique may be a useful tool for other diseases seen in wildlife rehabilitation.
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http://dx.doi.org/10.1638/2020-0111DOI Listing
April 2021

Occurrence of Mycoplasmas in Galapagos Sea Lions (Zalophus wollebaeki) and their Association with Other Respiratory Pathogens.

J Wildl Dis 2021 Mar 31. Epub 2021 Mar 31.

Galapagos Science Center, Universidad San Francisco de Quito. Isla San Cristóbal EC200150, Islas Galápagos, Ecuador.

During the 2018 breeding season, an outbreak of respiratory disease occurred among Galapagos sea lions (Zalophus wollebaeki) that inhabit rookeries near urban areas with introduced fauna such as dogs and cats. Several sea lions had nasal discharge and respiratory distress and were in poor body condition. Eighteen sea lions were captured for a general health assessment including collection of blood for serology and nasal discharge for culture and PCR. Samples were analyzed for 15 respiratory pathogens known to infect cats, dogs, and marine mammals. There was no evidence for interspecies pathogen transmission between Galapagos sea lions and domestic animals. Several bacterial pathogens associated with respiratory tract infection in the California sea lion (Zalophus californianus) were isolated. Mycoplasma spp. were identified by PCR in nasal discharge samples but were not the species commonly found in cats and dogs.
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http://dx.doi.org/10.7589/JWD-D-20-00081DOI Listing
March 2021

Demodectic mange in threatened southern sea otters (Enhydra lutris nereis).

Vet Dermatol 2021 Jun 19;32(3):211-e55. Epub 2021 Mar 19.

Marine Wildlife Veterinary Care and Research Center, California Department of Fish and Wildlife, 151 McAllister Way, Santa Cruz, CA, 95060, USA.

Background: Southern sea otters (Enhydra lutris nereis) rely on intact pelage for thermoregulation, and thus clinically significant demodicosis and associated alopecia can cause morbidity and death.

Hypothesis/objectives: This study aimed to describe lesions associated with follicular Demodex sp. infestation, estimate the prevalence and intensity of infestation, describe mite distribution across key anatomical regions, and assess mite presence or absence in relation to lesions and host risk factors.

Animals: Twenty necropsied, wild southern sea otters that stranded along the central California coast from 2005 to 2018.

Methods And Materials: Grossly normal and abnormal integument from the head, perineum, genitals, mamillary papillae and limbs was assessed microscopically for mites and mite-associated pathological findings.

Results: Intrafollicular mites were observed in the integument of 55% of otters and 20% had clinical demodicosis. Demodicosis was considered to be contributory to death or euthanasia in two cases. Although Demodex sp. mites often were observed microscopically in grossly normal skin, the presence of multiple densely-packed intrafollicular mites generally was associated with pigmentary incontinence, ectatic follicles, lymphoplasmacytic perifolliculitis, and neutrophilic and lymphoplasmacytic, dermal inflammation. Other findings included epidermal hyperplasia, orthokeratotic hyperkeratosis of epidermis and follicular epithelium, concurrent pyoderma and cell necrosis. Perioral integument, especially of the chin, had the highest prevalence of mites and the highest mite density, suggesting facial contact as a means of mite transmission.

Conclusions And Clinical Importance: Our research confirmed demodectic mange as a contributor to morbidity and mortality in sea otters, with important implications for clinical care, rehabilitation and conservation.
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http://dx.doi.org/10.1111/vde.12947DOI Listing
June 2021

Unlocking the Role of a Genital Herpesvirus, Otarine Herpesvirus 1, in California Sea Lion Cervical Cancer.

Animals (Basel) 2021 Feb 13;11(2). Epub 2021 Feb 13.

Veterinary Sciences, The Marine Mammal Center, Sausalito, CA 94965, USA.

Urogenital carcinoma in California sea lions () is the most common cancer of marine mammals. Primary tumors occur in the cervix, vagina, penis, or prepuce and aggressively metastasize resulting in death. This cancer has been strongly associated with a sexually transmitted herpesvirus, otarine herpesvirus 1 (OtHV1), but the virus has been detected in genital tracts of sea lions without cancer and a causative link has not been established. To determine if OtHV1 has a role in causing urogenital carcinoma we sequenced the viral genome, quantified viral load from cervical tissue from sea lions with ( = 95) and without ( = 163) urogenital carcinoma, and measured viral mRNA expression using in situ mRNA hybridization (Basescope) to quantify and identify the location of OtHV1 mRNA expression. Of the 95 sea lions diagnosed with urogenital carcinoma, 100% were qPCR positive for OtHV1, and 36% of the sea lions with a normal cervix were positive for the virus. The non-cancer OtHV1 positive cases had significantly lower viral loads in their cervix compared to the cervices from sea lions with urogenital carcinoma. The OtHV1 genome had several genes similar to the known oncogenes, and RNA in situ hybridization demonstrated high OtHV1 mRNA expression within the carcinoma lesions but not in normal cervical epithelium. The high viral loads, high mRNA expression of OtHV1 in the cervical tumors, and the presence of suspected OtHV1 oncogenes support the hypothesis that OtHV1 plays a significant role in the development of sea lion urogenital carcinoma.
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http://dx.doi.org/10.3390/ani11020491DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7918579PMC
February 2021

Fresh water skin disease in dolphins: a case definition based on pathology and environmental factors in Australia.

Sci Rep 2020 12 15;10(1):21979. Epub 2020 Dec 15.

Marine Mammal Foundation, Hampton East 3188, PO Box 2046, Victoria, Australia.

A distinct ulcerative dermatitis known as "freshwater skin disease" is an emerging clinical and pathological presentation in coastal cetaceans worldwide. In Australia, two remarkably similar mortality events enabled the creation of a case definition based on pathology and environmental factors. The first affected a community of endemic Tursiops australis in the Gippsland Lakes, Victoria, while the second occurred among T. aduncus resident in the Swan-Canning River system, Western Australia. The common features of both events were (1) an abrupt and marked decrease in salinity (from > 30ppt to < 5ppt) due to rainfall in the catchments, with hypo-salinity persisting weeks to months, and (2) dermatitis characterized grossly by patchy skin pallor that progressed to variable circular or targetoid, often raised, and centrally ulcerated lesions covering up to 70% of the body surface. The affected skin was often colonized by a variety of fungal, bacterial and algal species that imparted variable yellow, green or orange discoloration. Histologic lesions consisted of epidermal hydropic change leading to vesiculation and erosion; alternately, or in addition, the formation of intra-epithelial pustules resulting in ulceration and hypodermal necrosis. Thus, the environmental factors and characteristic pathologic lesions, are necessary components of the case definition for freshwater skin disease.
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http://dx.doi.org/10.1038/s41598-020-78858-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7738556PMC
December 2020

A novel quantitative real-time PCR diagnostic assay for fecal and nasal swab detection of an otariid lungworm, .

Int J Parasitol Parasites Wildl 2020 Aug 18;12:85-92. Epub 2020 May 18.

Smith College, Department of Biological Sciences, Northampton, MA, 01063, USA.

also known as sea lion lungworm, is a metastrongyloid nematode that infects otariid hosts, such as the charismatic California sea lion, causes bronchointerstitial pneumonia, respiratory distress, reduced ability to swim, dive and hunt and as a result, increased mortality particularly in young animals. Respiratory disease is a leading cause of stranding and admission to rehabilitation centers on the Pacific coast. Low-coverage genomic sequencing of four individuals analyzed through Galaxy's RepeatExplorer identified a novel repeat DNA family we employed to design a sensitive quantitative PCR (qPCR) assay for diagnosing infections from fecal or sputum samples. The assay detects as little as 10 fg of DNA and a linear regression model developed using a standard curve can be used to estimate the concentration of DNA in a sample, ± 0.015 ng. This knowledge can be leveraged to estimate the level of parasite burden, which can be used to design improved treatments for animals in rehabilitation. Improved treatment of infections will aid in more animals being successfully released back into the wild.
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http://dx.doi.org/10.1016/j.ijppaw.2020.04.012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7256429PMC
August 2020

Cranial crassicaudiasis in two coastal dolphin species from South Africa is predominantly a disease of immature individuals.

Dis Aquat Organ 2020 Apr 30;139:93-102. Epub 2020 Apr 30.

Cetacean Conservation Medicine Group, Peruvian Centre for Cetacean Research, Museo de Delfines, Lima 20, Peru.

Crassicauda spp. (Nematoda) infest the cranial sinuses of several odontocetes, causing diagnostic trabecular osteolytic lesions. We examined skulls of 77 Indian Ocean humpback dolphins Sousa plumbea and 69 Indo-Pacific bottlenose dolphins Tursiops aduncus, caught in bather-protecting nets off KwaZulu-Natal (KZN) from 1970-2017, and skulls of 6 S. plumbea stranded along the southern Cape coast in South Africa from 1963-2002. Prevalence of cranial crassicaudiasis was evaluated according to sex and cranial maturity. Overall, prevalence in S. plumbea and T. aduncus taken off KZN was 13 and 31.9%, respectively. Parasitosis variably affected 1 or more cranial bones (frontal, pterygoid, maxillary and sphenoid). No significant difference was found by gender for either species, allowing sexes to be pooled. However, there was a significant difference in lesion prevalence by age, with immature T. aduncus 4.6 times more likely affected than adults, while for S. plumbea, the difference was 6.5-fold. As severe osteolytic lesions are unlikely to heal without trace, we propose that infection is more likely to have a fatal outcome for immature dolphins, possibly because of incomplete bone development, lower immune competence in clearing parasites or an over-exuberant inflammatory response in concert with parasitic enzymatic erosion. Cranial osteolysis was not observed in mature males (18 S. plumbea, 21 T. aduncus), suggesting potential cohort-linked immune-mediated resistance to infestation. Crassicauda spp. may play a role in the natural mortality of S. plumbea and T. aduncus, but the pathogenesis and population level impact remain unknown.
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http://dx.doi.org/10.3354/dao03468DOI Listing
April 2020

Environmental persistence and disinfectant susceptibility of Klebsiella pneumoniae recovered from pinnipeds stranded on the California Coast.

Vet Microbiol 2020 Feb 17;241:108554. Epub 2019 Dec 17.

Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California, Davis, CA, 95616, USA.

Hypermucoviscous K. pneumoniae (HMV) are emergent zoonotic pathogens associated with increased invasiveness and pathogenicity in terrestrial and marine mammals. In this study, HMV and non-HMV isolates recovered from stranded pinnipeds were used to investigate: 1) their persistence in sea and fresh water microcosms at 10 and 20°C, 2) their capacity to form biofilms, and 3) the biocide efficacy of four disinfectants on their planktonic and biofilm phenotypes. Results indicated that although HMV isolates were significantly more mucoviscous, non-HMV isolates displayed significantly greater capacity to form biofilms (p < 0.05). Additionally, non-HMV isolates persisted in greater numbers in both sea- and freshwater, particularly at 20°C. These two phenomena could be associated with the greater growth observed for non-HMV isolates in in-vitro growth-curve assays (p < 0.05). Similar susceptibility to disinfectants was detected in HMV and non-HMV isolates when exposed for 24 h; however, the minimal biofilm disinfectant eradication concentration for HMV isolates was significantly higher than that for non-HMV when exposed to disinfectants for 0.5 h. This information should be taken into consideration when developing biosecurity protocols in facilities holding marine mammals in captivity.
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http://dx.doi.org/10.1016/j.vetmic.2019.108554DOI Listing
February 2020

Domestic sheep and bighorn sheep carry distinct gammaherpesviruses belonging to the genus Macavirus.

Virus Res 2019 10 21;272:197729. Epub 2019 Aug 21.

Animal Disease Research Unit-ARS-USDA, Pullman, WA, USA; Depart of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA.

The genus Macavirus of the subfamily Gammaherpesvirinae comprises two genetically distinct lineages of lymphotropic viruses. One of these lineages includes viruses that can cause malignant catarrhal fever (MCF), which are known as MCF viruses (MCFV). All MCFVs are genetically and antigenically related but carried by different hosts. In this study, we report the recognition of new MCFV carried by bighorn sheep. The virus was first identified in a bighorn sheep from Banff National Park, Alberta, Canada. Analysis of a conserved region of the viral DNA polymerase gene of the virus carried by this bighorn sheep showed 85.88% nucleotide identity to the MCFV carried by domestic sheep, ovine herpesvirus 2 (OvHV-2). Further investigation of bighorn samples obtained from animals in the US and Canada showed 98.87-100% identity to the DNA polymerase sequence of the first bighorn in the study. Phylogenetic analysis indicated that the MCFV carried by bighorn sheep is closely related but distinct from OvHV-2. Epidemiological and virulence features of the newly recognized MCFV are still unknown and warrant further investigation. Considering the current nomenclature for MCFVs, we suggest a tentative designation of ovine herpesvirus-3 (OvHV-3) for this newly identified bighorn sheep MCFV.
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http://dx.doi.org/10.1016/j.virusres.2019.197729DOI Listing
October 2019

Polyphasic Rhabdomyositis in California Sea Lions (): Pathology and Potential Causes.

Vet Pathol 2019 07 14;56(4):619-629. Epub 2019 Apr 14.

3 The Marine Mammal Center, Sausalito, CA, USA.

A myositis syndrome has been recognized for more than a decade in California sea lions (CSLs; ) but a detailed description of the lesions and potential causes of this condition is lacking. The tissues of 136 stranded CSLs with rhabdomyositis were examined. Rhabdomyositis was considered incidental in 67% (91/136) of the CSLs, and a factor contributing to the animal stranding (significant rhabdomyositis) in 33% (45/136). Of the 91 cases with incidental rhabdomyositis, lesions consisted of a few small foci of lymphohistiocytic inflammation. Of the 45 cases with significant rhabdomyositis, 28 (62%) also presented with major comorbidities such as leptospirosis (2 animals) and domoic acid toxicosis (6 animals), whereas 17 (38%) had severe polyphasic rhabdomyositis as the only major disease process associated with mortality. In these animals, most striated muscles had multiple white streaks and diffuse atrophy. Microscopically, there was myofiber necrosis surrounded by lymphocytes and histiocytes admixed with areas of myofiber regeneration, and/or moderate to severe rhabdomyocyte atrophy usually adjacent to intact cysts. At the interface of affected and normal muscle, occasional T lymphocytes infiltrated the sarcoplasm of intact myocytes, and occasional myofibers expressed MHCII proteins in the sarcoplasm. antibody titers and cyst burden were higher in animals with significant polymyositis antibody titers of (26125 ± 2164, 4.5 ± 1.2 cysts per section) and active myonecrosis than animals with incidental rhabdomyositis antibody titers of (7612 ± 1042, 1.7 ± 0.82 cysts per section). The presented findings suggest that infection and immune-mediated mechanisms could be associated with significant polyphasic rhabdomyositis in CSLs.
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http://dx.doi.org/10.1177/0300985819829526DOI Listing
July 2019

Pathology and molecular epidemiology of Mycobacterium pinnipedii tuberculosis in native New Zealand marine mammals.

PLoS One 2019 12;14(2):e0212363. Epub 2019 Feb 12.

AgResearch, Palmerston North, New Zealand.

Mycobacterium pinnipedii causes tuberculosis in a number of pinniped species, and transmission to cattle and humans has been reported. The aims of this study were to: characterize the pathology and prevalence of tuberculosis in New Zealand marine mammals; use molecular diagnostic methods to confirm and type the causal agent; and to explore relationships between type and host characteristics. Tuberculosis was diagnosed in 30 pinnipeds and one cetacean. Most affected pinnipeds had involvement of the pulmonary system, supporting inhalation as the most common route of infection, although ingestion was a possible route in the cetacean. PCR for the RD2 gene confirmed M. pinnipedii as the causal agent in 23/31 (74%) cases (22 using DNA from cultured organisms, and one using DNA from formalin-fixed paraffin-embedded (FFPE) tissue), including the first published report in a cetacean. RD2 PCR results were compared for 22 cases where both cultured organisms and FFPE tissues were available, with successful identification of M. pinnipedii in 7/22 (31.8%). In cases with moderate to large numbers of acid-fast bacilli, RD2 PCR on FFPE tissue provided a rapid, inexpensive method for confirming M. pinnipedii infection without the need for culture. VNTR typing distinguished New Zealand M. pinnipedii isolates from M. pinnipedii isolated from Australian pinnipeds and from common types of M. bovis in New Zealand. Most (16/18) M. pinnipedii isolates from New Zealand sea lions were one of two common VNTR types whereas the cetacean isolate was a type detected previously in New Zealand cattle.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0212363PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6372207PMC
November 2019

Primary Pleural Squamous Cell Carcinoma in a Free-Ranging River Otter ().

J Wildl Dis 2019 07 31;55(3):728-732. Epub 2019 Jan 31.

3 The Marine Mammal Center, 2000 Bunker Road, Sausalito, California 94965, USA.

An adult female North American river otter () presented with multiple intrathoracic masses identified histologically as squamous cell carcinoma. Immunohistochemical staining patterns for high- molecular-weight keratin, p40, p63, calretinin, and TTF-1, along with the gross and histologic findings, indicated a primary pleural squamous cell carcinoma as the most likely diagnosis.
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http://dx.doi.org/10.7589/2018-07-181DOI Listing
July 2019

Corrigendum to 'Detecting co-infections of Echinococcus multilocularis and Echinococcus canadensis in coyotes and red foxes in Alberta, Canada using real-time PCR' [IJP: Parasites and Wildlife 7 (2018) 111-115].

Int J Parasitol Parasites Wildl 2018 12 29;7(3):463. Epub 2018 Jul 29.

Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Alberta, T2N 4Z6, Canada.

[This corrects the article DOI: 10.1016/j.ijppaw.2018.03.001.].
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http://dx.doi.org/10.1016/j.ijppaw.2018.07.006DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6287575PMC
December 2018

Domoic acid in California sea lion fetal fluids indicates continuous exposure to a neuroteratogen poses risks to mammals.

Harmful Algae 2018 11 7;79:53-57. Epub 2018 Jul 7.

The Marine Mammal Center, 2000 Bunker Road, Sausalito, CA 94965, United States.

Domoic acid (DA) is a neuroexcitotoxic amino acid that is naturally produced by some species of marine diatoms during harmful algal blooms (HABs). The toxin is transferred through the food web from plantivorous fish and shellfish to marine mammals resulting in significant morbidity and mortality. Due to the timing and location of DA producing HABs, it is well documented that pregnant female California sea lions (CSL) are regularly exposed to DA through their diet thereby posing exposure risks to a neuroteratogen in developing fetuses. In the present study, fluids from 36 fetuses sampled from naturally exposed pregnant CSLs were examined for DA. Domoic acid was detected in 79% of amniotic fluid (n = 24), 67% of allantoic fluid (n = 9), 75% of urine (n = 4), 41% of meconium (n = 17) and 29% of stomach content (n = 21) samples opportunistically collected from CSL fetuses. The distribution of DA in fetal samples indicates an increased prenatal exposure risk due to recirculation of DA in fetal fluids and continuous exposure to the developing brain.
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http://dx.doi.org/10.1016/j.hal.2018.06.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7297052PMC
November 2018

Detecting co-infections of and in coyotes and red foxes in Alberta, Canada using real-time PCR.

Int J Parasitol Parasites Wildl 2018 Aug 2;7(2):111-115. Epub 2018 Mar 2.

Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, Alberta, T2N 4Z6, Canada.

The continued monitoring of species in intermediate and definitive hosts is essential to understand the eco-epidemiology of these parasites, as well to assess their potential impact on public health. In Canada, co-infections of and based on genetic characterization have been recently reported in wolves, but not yet in other possible hosts such as coyotes and foxes. In this study, we aimed to develop a quantitative real-time PCR assay to detect and and estimate the occurrence of co-infections while inferring about the relative abundance of the two parasites within hosts. We tested DNA extracted from aliquots of spp. specimens collected from intestinal tracts of 24 coyote and 16 fox carcasses from Alberta, Canada. We found evidence of co-infections of and in 11 out of 40 (27%) samples, with 8 out of 24 (33%) in coyote samples and 3 out of 16 (19%) in red fox samples. DNA concentrations were estimated in three samples with Cq values within the range of the standard curve for both parasites; two of them presented higher DNA concentrations of than . The use of qPCR aided detection of co-infections when morphological discrimination was difficult and quantification of DNA for samples within the standard curve. This is the first molecularly confirmed record of in coyotes and the first evidence of co-infections of and in coyotes and red foxes.
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http://dx.doi.org/10.1016/j.ijppaw.2018.03.001DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6031960PMC
August 2018

HYPERMUCOVISCOUS KLEBSIELLA PNEUMONIAE ISOLATES FROM STRANDED AND WILD-CAUGHT MARINE MAMMALS OF THE US PACIFIC COAST: PREVALENCE, PHENOTYPE, AND GENOTYPE.

J Wildl Dis 2018 10 7;54(4):659-670. Epub 2018 May 7.

1   Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California, Davis, 1 Garrod Drive, Davis, California 95616, USA.

Emergent hypermucoviscous (HMV) strains of Klebsiella pneumoniae have been reported in multiple marine mammal species; however, there is limited information regarding the epidemiology and pathogenesis of this infection in these species. We determined the prevalence of HMV K. pneumoniae in wild-caught and stranded marine mammal populations on the US Pacific Coast. Samples were collected from 270 free-ranging California sea lions (CSLs; Zalophus californianus) captured at three discrete sampling sites and from 336 stranded marine mammals of various species. We recovered HMV K. pneumoniae only from CSLs, with a prevalence of 1.5% (4 of 275) in stranded animals, compared with 1.1% (3 of 270) in wild-caught animals. We assessed the phenotypic and genotypic variability of recovered HMV K. pneumoniae isolates recovered from CSLs ( n=11) and of archival HMV and non-HMV isolates from stranded marine mammals ( n=19). All but two HMV isolates were of the K2 serotype, whereas none of the non-HMV isolates belonged to this serotype. Of the HMV isolates, 96% (24 of 25) were PCR positive for the HMV-associated gene p- rmpA, whereas 92% (23 of 25) were PCR positive for p- rmpA2. Genetic fingerprinting by repetitive extragenic palindromic PCR showed four discrete clusters, demonstrating genotypic variability that loosely correlated with phenotype. Antimicrobial susceptibility testing revealed all isolates from stranded CSLs were susceptible to ceftiofur, indicating this antimicrobial agent is an appropriate choice for treatment of HMV K. pneumoniae infections in stranded CSLs. Our culture assay could reliably detect HMV K. pneumoniae from concentrations as low as 10 colony-forming units per milligram of feces. We identified the presence of HMV K. pneumoniae in both wild-caught and stranded CSLs from the US Pacific Coast and highlight the need for further studies to evaluate the potential impact of this pathogen on marine mammal health.
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http://dx.doi.org/10.7589/2017-07-178DOI Listing
October 2018

Vasculitis and Thrombosis due to the Sea Lion Lungworm, Parafilaroides decorus, in a Guadalupe Fur Seal ( Arctocephalus philippii townsendi).

J Wildl Dis 2018 07 1;54(3):638-641. Epub 2018 May 1.

3 The Marine Mammal Center, 2000 Bunker Rd., Sausalito, California 94965, USA.

A free-ranging, male, yearling Guadalupe fur seal ( Arctocephalus philippii townsendi) died due to multifocal verminous vasculitis with thrombosis and several embolic infarcts in liver, kidney, and brain. Nematodes extracted from lung blood vessels were identified as Parafilaroides decorus, a parasite normally found in alveoli of California sea lions ( Zalophus californianus).
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http://dx.doi.org/10.7589/2017-12-291DOI Listing
July 2018

Prevalence of Urogenital Carcinoma in Stranded California Sea Lions ( Zalophus californianus) from 2005-15.

J Wildl Dis 2018 07 2;54(3):581-586. Epub 2018 Mar 2.

2 The Marine Mammal Center, 2000 Bunker Road, Sausalito, California 94965, USA.

Urogenital carcinoma is common in wild California sea lions ( Zalophus californianus) along the west coast of the US. From 1979 to 1994, this cancer was observed in 18% (66/370) of necropsied subadult and adult sea lions at The Marine Mammal Center in Sausalito, California. A retrospective review of records from 1 January 2005 to 31 December 2015 was performed to characterize prevalence and characteristics of cancer over this decade. Fourteen percent (263/1917) of necropsied sea lions had cancer, of which 90% (237/263) were urogenital carcinoma. The prevalence of urogenital carcinoma was significantly higher in adults compared to juveniles and subadults. Advanced-stage disease with metastases was identified histologically in 78% (182/232) of cases and was the cause of death in 95% (172/182) of these cases. Metastases were most common in lung and lymph nodes, and hydronephrosis, secondary to ureter obstruction by metastases, was identified in 62% (114/185) of animals with advanced disease. No significant temporal change in prevalence was detected over the decade, and this highly aggressive, fatal cancer remains common in stranded California sea lions.
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http://dx.doi.org/10.7589/2017-08-208DOI Listing
July 2018

Epidemiology of tattoo skin disease in captive common bottlenose dolphins (Tursiops truncatus): Are males more vulnerable than females?

J Appl Anim Welf Sci 2018 Oct-Dec;21(4):305-315. Epub 2018 Jan 22.

b Department of Veterinary Science, The Marine Mammal Center, Fort Cronkhite , Sausalito , California , USA.

Clinical and epidemiological features of tattoo skin disease (TSD) are reported for 257 common bottlenose dolphins held in 31 facilities in the Northern Hemisphere. Photographs and biological data of 146 females and 111 males were analyzed. Dolphins were classified into three age classes: 0-3 years, 4-8 years, and older than 9 years. From 2012 to 2014, 20.6% of the 257 dolphins showed clinical TSD. The youngest dolphins with tattoo lesions were 14 and 15 months old. TSD persisted from 4 to 65 months in 30 dolphins. Prevalence varied between facilities from 5.6% to 60%, possibly reflecting variation in environmental factors. Unlike in free-ranging Delphinidae, TSD prevalence was significantly higher in males (31.5%) than in females (12.3%). Infection was age-dependent only in females. Prevalence of very large tattoos was also higher in males (28.6%) than in females (11.1%). These data suggest that male T. truncatus are more vulnerable to TSD than females, possibly because of differences in immune response and susceptibility to captivity-related stress.
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http://dx.doi.org/10.1080/10888705.2017.1421076DOI Listing
January 2019

Brucellosis in Endangered Hector's Dolphins (Cephalorhynchus hectori).

Vet Pathol 2017 09 11;54(5):838-845. Epub 2017 May 11.

1 Ministry for Primary Industries, Investigation and Diagnostic Centers and Response, Wallaceville, New Zealand.

Brucella spp infections of marine mammals are often asymptomatic but have been associated with reproductive losses and deaths. Zoonotic infections originating from marine isolates have also been described. Hector's dolphins (Cephalorhynchus hectori) are an endangered species with a declining population, and the role of infectious disease in population dynamics is not fully understood. In this study, 27 Hector's dolphins found dead around the New Zealand coastline between November 2006 and October 2010 were evaluated for lesions previously associated with cetacean brucellosis. Tissues were examined using histological, immunohistochemical, and molecular (polymerase chain reaction [PCR]) techniques. Seven of 27 dolphins (26%) had at least 1 tissue that was positive on PCR for Brucella spp. Lesions consistent with brucellosis were present in 10 of 27 (37%) dolphins, but in 8 of these dolphins Brucella infection could not be demonstrated in lesional tissues. Two dolphins (7%) were diagnosed with active brucellosis: 1 female with placentitis and metritis, and 1 stillborn male fetus. Brucella identified in these 2 dolphins had genetic similarity (99%) to Brucella pinnipedialis. The omp2a gene amplicon from the uterus of the female had 100% homology with ST27 genotype isolates from a human in New Zealand and a bottlenose dolphin of Pacific origin. The remaining 5 PCR-positive dolphins were assessed as having asymptomatic or latent infection. While most Brucella infections identified in this study appeared to be subclinical, the finding of 2 dolphins with reproductive disease due to Brucella infection suggests that this disease has the potential to affect reproductive success in this species.
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http://dx.doi.org/10.1177/0300985817707023DOI Listing
September 2017

Cetacean Morbillivirus in Odontocetes Stranded along the Central California Coast, USA, 2000-15.

J Wildl Dis 2017 04 25;53(2):386-392. Epub 2017 Jan 25.

1 Marine Mammal Center, 2000 Bunker Road, Sausalito, California 94965, USA.

Effects of cetacean morbillivirus (CeMV) on dolphins vary from causing epidemics to subclinical infections. The former have been documented in the North Atlantic Ocean and Mediterranean Sea but not in the North Pacific Ocean, and the reasons for this are unknown. To explore the distribution of this virus in areas that have not experienced epidemics, we reviewed evidence for morbilliviral infection in odontocetes stranded along the California coast, US from 2000-15. Nine of 212 animals examined histologically had lesions compatible with morbilliviral infection, and 11 were tested for CeMV via reverse transcriptase-PCR. One striped dolphin ( Stenella coeruleoalba ) was PCR positive, and the sequenced product was most closely related to sequences in two strains found in cetaceans in Hawaii. This study suggests that CeMV may be a cause of morbidity and a rare contributor to mortality in cetaceans stranding along the California coast. Additional work is needed to understand CeMV distribution and host species susceptibility in this region.
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http://dx.doi.org/10.7589/2016-09-219DOI Listing
April 2017

Sheep-Associated Malignant Catarrhal Fever-Like Skin Disease in a Free-Ranging Bighorn Sheep ( Ovis canadensis ), Alberta, Canada.

J Wildl Dis 2017 01 17;53(1):153-158. Epub 2016 Oct 17.

1 Faculty of Veterinary Medicine, Department of Ecosystem and Public Health, University of Calgary, 3280 Hospital Dr. NW, Calgary, Alberta, Canada, T2N 4Z6.

Malignant catarrhal fever-like clinical disease was diagnosed in a free-ranging bighorn sheep ( Ovis canadensis ) from Alberta, Canada, in June 2015. Antemortem and gross pathology findings included muscle atrophy, marked weight loss, and bilaterally symmetric alopecia with hyperpigmentation and crusting over the face, medial surfaces of the pinnae, dorsal trunk, distal limbs, perineal area, and tail. Histologically, the skin lesions were characterized by granulomatous mural folliculitis with numerous multinucleated giant cells and fewer lymphocytes and eosinophils consistent with previous reports of chronic ovine herpesvirus-2 (OvHV-2) infection. Multiple skin samples were positive for OvHV-2 DNA on PCR, and on partial sequencing of the viral DNA, there was 94% homology with reference GenBank OvHV-2. Quantitative PCR confirmed an increased level of OvHV-2 DNA in the lesional skin tissues. Based on exclusion of other disease processes, gross and histological lesions, PCR, and viral DNA sequencing results, a diagnosis of OvHV-2-mediated malignant catarrhal fever-like dermatitis was made.
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http://dx.doi.org/10.7589/2016-05-103DOI Listing
January 2017

Contagious Ecthyma, Rangiferine Brucellosis, and Lungworm Infection in a Muskox ( Ovibos moschatus ) from the Canadian Arctic, 2014.

J Wildl Dis 2016 07 10;52(3):719-24. Epub 2016 Jun 10.

1 Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, Alberta T2N 4Z6, Canada;

An adult male muskox ( Ovibos moschatus ), harvested on 26 August 2014 on Victoria Island, Nunavut, in the Canadian Arctic, had proliferative dermatitis on the muzzle and fetlocks suggestive of contagious ecthyma or orf (Parapoxvirus). Histopathologic features of the lesions were consistent with this diagnosis. Orf virus DNA, phylogenetically similar to an isolate from a captive muskox of the Minnesota Zoo, US, was detected in the lesions by PCR using Parapoxvirus primers. Additionally, there was a metaphyseal abscess with a cortical fistula in the right metacarpus from which Brucella suis biovar 4 was isolated and identification supported by PCR. Brucella spp. antibodies were detected in serum. Finally, 212 nodules were dissected from the lungs. Fecal analysis and lung examination demonstrated co-infection with the lungworms Umingmakstrongylus pallikuukensis and Varestrongylus eleguneniensis. The zoonotic potential of orf and rangiferine brucellosis adds an important public health dimension to this case, particularly given that muskoxen are a valuable source of food for Arctic residents. Careful examination of these pathogens at a population level is needed as they may contribute to muskox population decline and potentially constitute a driver of food insecurity for local communities. This case underscores the importance of wildlife health surveillance as a management tool to conserve wildlife populations and maintain food security in subsistence-oriented communities.
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http://dx.doi.org/10.7589/2015-12-327DOI Listing
July 2016

Morphological variability and molecular identification of Uncinaria spp. (Nematoda: Ancylostomatidae) from grizzly and black bears: new species or phenotypic plasticity?

J Parasitol 2015 Apr 30;101(2):182-92. Epub 2014 Dec 30.

Department of Ecosystem and Public Health, Faculty of Veterinary Medicine, University of Calgary, 3280 Hospital Drive NW, Calgary, AB T2N 4Z6, Canada.

The hookworms Uncinaria rauschi Olsen, 1968 and Uncinaria yukonensis ( Wolfgang, 1956 ) were formally described from grizzly ( Ursus arctos horribilis) and black bears ( Ursus americanus ) of North America. We analyzed the intestinal tracts of 4 grizzly and 9 black bears from Alberta and British Columbia, Canada and isolated Uncinaria specimens with anatomical traits never previously documented. We applied morphological and molecular techniques to investigate the taxonomy and phylogeny of these Uncinaria parasites. The morphological analysis supported polymorphism at the vulvar region for females of both U. rauschi and U. yukonensis. The hypothesis of morphological plasticity for U. rauschi and U. yukonensis was confirmed by genetic analysis of the internal transcribed spacers (ITS-1 and ITS-2) of the nuclear ribosomal DNA. Two distinct genotypes were identified, differing at 5 fixed sites for ITS-1 (432 base pairs [bp]) and 7 for ITS-2 (274 bp). Morphometric data for U. rauschi revealed host-related size differences: adult U. rauschi were significantly larger in black bears than in grizzly bears. Interpretation of these results, considering the historical biogeography of North American bears, suggests a relatively recent host-switching event of U. rauschi from black bears to grizzly bears which likely occurred after the end of the Wisconsin glaciation. Phylogenetic maximum parsimony (MP) and maximum likelihood (ML) analyses of the concatenated ITS-1 and ITS-2 datasets strongly supported monophyly of U. rauschi and U. yukonensis and their close relationship with Uncinaria stenocephala (Railliet, 1884), the latter a parasite primarily of canids and felids. Relationships among species within this group, although resolved by ML, were unsupported by MP and bootstrap resampling. The clade of U. rauschi, U. yukonensis, and U. stenocephala was recovered as sister to the clade represented by Uncinaria spp. from otariid pinnipeds. These results support the absence of strict host-parasite co-phylogeny for Uncinaria spp. and their carnivore hosts. Phylogenetic relationships among Uncinaria spp. provided a framework to develop the hypothesis of similar transmission patterns for the closely related U. rauschi, U. yukonensis, and U. stenocephala.
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http://dx.doi.org/10.1645/14-621.1DOI Listing
April 2015

Cetacean morbillivirus: current knowledge and future directions.

Viruses 2014 Dec 22;6(12):5145-81. Epub 2014 Dec 22.

Department of Ecosystem and Public Health, University of Calgary, Calgary, AL T2N 4Z6, Canada.

We review the molecular and epidemiological characteristics of cetacean morbillivirus (CeMV) and the diagnosis and pathogenesis of associated disease, with six different strains detected in cetaceans worldwide. CeMV has caused epidemics with high mortality in odontocetes in Europe, the USA and Australia. It represents a distinct species within the Morbillivirus genus. Although most CeMV strains are phylogenetically closely related, recent data indicate that morbilliviruses recovered from Indo-Pacific bottlenose dolphins (Tursiops aduncus), from Western Australia, and a Guiana dolphin (Sotalia guianensis), from Brazil, are divergent. The signaling lymphocyte activation molecule (SLAM) cell receptor for CeMV has been characterized in cetaceans. It shares higher amino acid identity with the ruminant SLAM than with the receptors of carnivores or humans, reflecting the evolutionary history of these mammalian taxa. In Delphinidae, three amino acid substitutions may result in a higher affinity for the virus. Infection is diagnosed by histology, immunohistochemistry, virus isolation, RT-PCR, and serology. Classical CeMV-associated lesions include bronchointerstitial pneumonia, encephalitis, syncytia, and lymphoid depletion associated with immunosuppression. Cetaceans that survive the acute disease may develop fatal secondary infections and chronic encephalitis. Endemically infected, gregarious odontocetes probably serve as reservoirs and vectors. Transmission likely occurs through the inhalation of aerosolized virus but mother to fetus transmission was also reported.
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http://dx.doi.org/10.3390/v6125145DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4276946PMC
December 2014

Phocine distemper virus: current knowledge and future directions.

Viruses 2014 Dec 22;6(12):5093-134. Epub 2014 Dec 22.

Cetacean Conservation Medicine Group (CMED), Peruvian Centre for Cetacean Research (CEPEC), Pucusana, Lima 20, Peru.

Phocine distemper virus (PDV) was first recognized in 1988 following a massive epidemic in harbor and grey seals in north-western Europe. Since then, the epidemiology of infection in North Atlantic and Arctic pinnipeds has been investigated. In the western North Atlantic endemic infection in harp and grey seals predates the European epidemic, with relatively small, localized mortality events occurring primarily in harbor seals. By contrast, PDV seems not to have become established in European harbor seals following the 1988 epidemic and a second event of similar magnitude and extent occurred in 2002. PDV is a distinct species within the Morbillivirus genus with minor sequence variation between outbreaks over time. There is now mounting evidence of PDV-like viruses in the North Pacific/Western Arctic with serological and molecular evidence of infection in pinnipeds and sea otters. However, despite the absence of associated mortality in the region, there is concern that the virus may infect the large Pacific harbor seal and northern elephant seal populations or the endangered Hawaiian monk seals. Here, we review the current state of knowledge on PDV with particular focus on developments in diagnostics, pathogenesis, immune response, vaccine development, phylogenetics and modeling over the past 20 years.
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http://dx.doi.org/10.3390/v6125093DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4276944PMC
December 2014

Cetacean morbillivirus in coastal Indo-Pacific bottlenose dolphins, Western Australia.

Emerg Infect Dis 2014 Apr;20(4):666-70

Cetacean morbillivirus (CeMV) has caused several epizootics in multiple species of cetaceans globally and is an emerging disease among cetaceans in Australia. We detected CeMV in 2 stranded coastal Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Western Australia. Preliminary phylogenetic data suggest that this virus variant is divergent from known strains.
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http://dx.doi.org/10.3201/eid2004.131714DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3966363PMC
April 2014