Diagnostic investigation of new disease syndromes in farmed Australian saltwater crocodiles (Crocodylus porosus) reveals associations with herpesviral infection

Cathy Shilton, I JERRETT, Stephen Davis, Susan J Walsh, Suresh Benedict, Sally Isberg, Grahame Webb, Charlie Manolis, Tim Hyndman, D Phalen, G BROWN, L Melville

    Research output: Contribution to journalArticleResearchpeer-review

    Abstract

    Since 2006, 3 new disease syndromes have emerged in farmed saltwater crocodiles (Crocodylus porosus) in the Northern Territory of Australia. We describe the syndromes through a retrospective study of laboratory findings from 187 diagnostic cases submitted to Berrimah Veterinary Laboratories between 2005 and 2014. The first syndrome was characterized by conjunctivitis and/or pharyngitis (CP), primarily in hatchlings. Herpesviruses were isolated in primary crocodile cell culture, or were detected by PCR directly from conjunctiva or pharyngeal tissue, in 21 of 39 cases of CP (54%), compared with 9 of 64 crocodiles without the syndrome (14%, p < 0.0001). Chlamydiaceae were detected by PCR in conjunctiva or pharyngeal tissue of 55% of 29 CP cases tested, and of these, 81% also contained herpesvirus. The second syndrome occurred in juveniles and growers exhibiting poor growth, and was characterized histologically by systemic lymphoid proliferation and nonsuppurative encephalitis (SLPE). Herpesviruses were isolated or detected by PCR from at least 1 internal organ in 31 of 33 SLPE cases (94%) compared with 5 of 95 crocodiles without the syndrome (5%, p < 0.0001). The third syndrome, characterized by multifocal lymphohistiocytic infiltration of the dermis (LNS), occurred in 6 harvest-sized crocodiles. Herpesviruses were isolated from at least 1 skin lesion in 4 of these 6 cases. Although our study revealed strong associations between herpesvirus and the CP and SLPE syndromes, the precise nature of the role of herpesvirus, along with the pathogenesis and epidemiology of the syndromes, requires further investigation.
    Original languageEnglish
    Pages (from-to)279-290
    Number of pages12
    JournalJournal of Veterinary Diagnostic Investigation
    Volume28
    Issue number3
    DOIs
    Publication statusPublished - 2016

    Fingerprint

    Crocodylus porosus
    Alligators and Crocodiles
    crocodiles
    encephalitis
    Herpesviridae
    conjunctiva
    Infection
    infection
    Chlamydiaceae
    Encephalitis
    conjunctivitis
    Northern Territory
    dermis
    skin lesions
    Conjunctiva
    retrospective studies
    epidemiology
    growers
    Polymerase Chain Reaction
    cell culture

    Cite this

    Shilton, Cathy ; JERRETT, I ; Davis, Stephen ; Walsh, Susan J ; Benedict, Suresh ; Isberg, Sally ; Webb, Grahame ; Manolis, Charlie ; Hyndman, Tim ; Phalen, D ; BROWN, G ; Melville, L. / Diagnostic investigation of new disease syndromes in farmed Australian saltwater crocodiles (Crocodylus porosus) reveals associations with herpesviral infection. In: Journal of Veterinary Diagnostic Investigation. 2016 ; Vol. 28, No. 3. pp. 279-290.
    @article{9942ee525d104901ba465c3a0d0a528d,
    title = "Diagnostic investigation of new disease syndromes in farmed Australian saltwater crocodiles (Crocodylus porosus) reveals associations with herpesviral infection",
    abstract = "Since 2006, 3 new disease syndromes have emerged in farmed saltwater crocodiles (Crocodylus porosus) in the Northern Territory of Australia. We describe the syndromes through a retrospective study of laboratory findings from 187 diagnostic cases submitted to Berrimah Veterinary Laboratories between 2005 and 2014. The first syndrome was characterized by conjunctivitis and/or pharyngitis (CP), primarily in hatchlings. Herpesviruses were isolated in primary crocodile cell culture, or were detected by PCR directly from conjunctiva or pharyngeal tissue, in 21 of 39 cases of CP (54{\%}), compared with 9 of 64 crocodiles without the syndrome (14{\%}, p < 0.0001). Chlamydiaceae were detected by PCR in conjunctiva or pharyngeal tissue of 55{\%} of 29 CP cases tested, and of these, 81{\%} also contained herpesvirus. The second syndrome occurred in juveniles and growers exhibiting poor growth, and was characterized histologically by systemic lymphoid proliferation and nonsuppurative encephalitis (SLPE). Herpesviruses were isolated or detected by PCR from at least 1 internal organ in 31 of 33 SLPE cases (94{\%}) compared with 5 of 95 crocodiles without the syndrome (5{\%}, p < 0.0001). The third syndrome, characterized by multifocal lymphohistiocytic infiltration of the dermis (LNS), occurred in 6 harvest-sized crocodiles. Herpesviruses were isolated from at least 1 skin lesion in 4 of these 6 cases. Although our study revealed strong associations between herpesvirus and the CP and SLPE syndromes, the precise nature of the role of herpesvirus, along with the pathogenesis and epidemiology of the syndromes, requires further investigation.",
    author = "Cathy Shilton and I JERRETT and Stephen Davis and Walsh, {Susan J} and Suresh Benedict and Sally Isberg and Grahame Webb and Charlie Manolis and Tim Hyndman and D Phalen and G BROWN and L Melville",
    year = "2016",
    doi = "10.1177/1040638716642268",
    language = "English",
    volume = "28",
    pages = "279--290",
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    Shilton, C, JERRETT, I, Davis, S, Walsh, SJ, Benedict, S, Isberg, S, Webb, G, Manolis, C, Hyndman, T, Phalen, D, BROWN, G & Melville, L 2016, 'Diagnostic investigation of new disease syndromes in farmed Australian saltwater crocodiles (Crocodylus porosus) reveals associations with herpesviral infection', Journal of Veterinary Diagnostic Investigation, vol. 28, no. 3, pp. 279-290. https://doi.org/10.1177/1040638716642268

    Diagnostic investigation of new disease syndromes in farmed Australian saltwater crocodiles (Crocodylus porosus) reveals associations with herpesviral infection. / Shilton, Cathy; JERRETT, I; Davis, Stephen; Walsh, Susan J; Benedict, Suresh; Isberg, Sally; Webb, Grahame; Manolis, Charlie; Hyndman, Tim; Phalen, D; BROWN, G; Melville, L.

    In: Journal of Veterinary Diagnostic Investigation, Vol. 28, No. 3, 2016, p. 279-290.

    Research output: Contribution to journalArticleResearchpeer-review

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    AU - JERRETT, I

    AU - Davis, Stephen

    AU - Walsh, Susan J

    AU - Benedict, Suresh

    AU - Isberg, Sally

    AU - Webb, Grahame

    AU - Manolis, Charlie

    AU - Hyndman, Tim

    AU - Phalen, D

    AU - BROWN, G

    AU - Melville, L

    PY - 2016

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