Adam Polkinghorne

Epitheliocystis in fish: An emerging aquaculture disease with a global impact.

Publisher: Hindawi Limited

Date: 23-05-2018

DOI: 10.1111/TBED.12908

Abstract: Epitheliocystis is a skin and gill disease in fish caused by pathogenic intracellular bacteria. The disease has been reported in at least 90 species of marine and freshwater fish in both the southern and northern hemispheres. It affects a number of commercially important aquaculture species, including salmon, kingfish and bream. In infected fish, cysts typically develop in the gill epithelia, promoting the fusion of gill lamellae. Infections can lead to respiratory distress and death, particularly in cultured and juvenile fish with cases rarely reported in wild fish. Modern molecular techniques are challenging the conventional wisdoms regarding the epidemiology of epitheliocystis, showing now that a number of distinct bacterial pathogens from completely different phyla can cause this disease. Here, we review the state of knowledge, including updates on aetiology, host range, diagnosis and treatments. Traditionally, bacteria from the phylum Chlamydiae were the only known pathogenic agents of epitheliocystis, but aetiology is now recognized as being more complex, including a range of Proteobacteria. Notwithstanding recent advances in identifying the pathogens, the reservoirs and modes of transmission remain largely unknown. Recent genome sequencing of the growing number of epitheliocystis agents suggests that many bacteria causing this disease are unique to in idual species of fish. Environmental conditions that approach or exceed animals' physiological tolerances (e.g. atypical temperature, salinity or pH levels) are thought to contribute to disease development and progression. Empirical data and evidence concerning epidemiology, aetiology and treatments are, however, in many cases limited, highlighting the need for more work to better characterize this disease across the different hosts and locales affected.

Humoral immune response against two surface antigens of Chlamydia pecorum in vaccinated and naturally infected sheep

Publisher: Public Library of Science (PLoS)

Date: 30-11-2017

DOI: 10.1371/JOURNAL.PONE.0188370

Molecular evidence to suggest pigeon-type Chlamydia psittaci in association with an equine foal loss

Publisher: Hindawi Limited

Date: 19-01-2018

DOI: 10.1111/TBED.12817

Abstract: Chlamydia psittaci is an important avian pathogen with spillover from infected wild and domesticated birds also posing a risk to human health. We recently reported a case of C. psittaci equine placentitis associated with further spillover to humans. Molecular typing of this case revealed it belonged to the 6BC clade of C. psittaci, a globally distributed highly virulent set of strains, typically linked to infection spillover from parrots. Equine chlamydiosis associated with C. psittaci infection has previously been reported elsewhere in countries where parrots are not endemic, however, raising questions over the identity of infecting C. psittaci strains and the potential infection reservoirs. In this study, we describe the detection and molecular characterization of C. psittaci in a case of equine abortion in southern Queensland. Equine placenta and fresh liver and lung tissue from the necropsied foetus were positive by C. psittaci-specific qPCR. Chlamydia psittaci-specific multilocus sequence typing and ompA genotyping were used to further characterize the detected equine strains and an additional strain obtained from a dove from a different geographic region presenting with psittacosis. Molecular typing of this case revealed that the infecting equine strains were closely related to the C0sittaci detected in dove, all belonging to an evolutionary lineage of C. psittaci strains typically associated with infections of pigeons globally. This finding suggests a broader ersity of C. psittaci strains may be detected in horses and in association with reproductive loss, highlighting the need for an expansion of surveillance studies globally to understand the epidemiology of equine chlamydiosis and the associated zoonotic risk.

New and emerging chlamydial infections of creatures great and small

Publisher: Elsevier BV

Date: 07-2017

DOI: 10.1016/J.NMNI.2017.04.004

Mitochondrial genome sequencing reveals potential origins of the scabies mite Sarcoptes scabiei infesting two iconic Australian marsupials

Publisher: Springer Science and Business Media LLC

Date: 28-11-2017

DOI: 10.1186/S12862-017-1086-9

Detection of a range of genetically diverse chlamydiae in Australian domesticated and wild ungulates.

Publisher: Hindawi Limited

Date: 03-04-2019

DOI: 10.1111/TBED.13171

Abstract: Chlamydiae are globally widespread obligate intracellular bacteria, which several species are a well-recognized threat to human and animal health. In Australia, the most successful chlamydial species are the infamous koala pathogen C. pecorum, and C. psittaci, an emerging pathogen associated with zoonotic events. Little is known about infections caused by other chlamydial organisms in Australian livestock or wildlife. Considering that these hosts can be encountered by humans at the animal/human interface, in this study, we investigated genetic ersity of chlamydial organisms infecting Australian domesticated and wild ungulates. A total of 185 s les from 129 domesticated (cattle, horses, sheep, and pigs) and 29 wild (deer) ungulate hosts were screened with C. pecorum and C. psittaci species-specific assays, followed by a screen with pan-Chlamydiales assay. Overall, chlamydial DNA was detected in 120/185 (65%) s les, including all ungulate hosts. Species-specific assays further revealed that C. pecorum and C. psittaci DNA were detected in 27% (50/185) and 6% (11/185) of the s les, respectively, however from domesticated hosts only. A total of 46 "signature" 16S rRNA sequences were successfully resolved by sequencing and were used for phylogenetic analyses. Sequence analyses revealed that genetically erse novel as well as traditional chlamydial organisms infect an expanded range of ungulate hosts in Australia. Detection of the C. psittaci and C. pecorum in livestock, and novel taxa infecting horses and deer raises questions about the genetic make-up and pathogenic potential of these organisms, but also concerns about risks of spill-over between livestock, humans, and native wildlife.

Identification, characterisation and expression analysis of natural killer receptor genes in Chlamydia pecorum infected koalas (Phascolarctos cinereus)

Publisher: Springer Science and Business Media LLC

Date: 15-10-2015

DOI: 10.1186/S12864-015-2035-X

Population‐scale treatment informs solutions for control of environmentally transmitted wildlife disease

Publisher: Wiley

Date: 23-07-2019

DOI: 10.1111/1365-2664.13467

Abstract: Long‐term pathogen control or eradication in wildlife is rare and represents a major challenge in conservation. Control is particularly difficult for environmentally transmitted pathogens, including some of the most conservation‐critical wildlife diseases. We undertook a treatment programme aimed at population‐scale eradication of the environmentally transmitted Sarcoptes scabiei mite (causative agent of sarcoptic mange) during an epizootic in bare‐nosed wombats ( Vombatus ursinus ). Field trial results were used to parameterize a mechanistic host‐disease model that explicitly described indirect transmission, host behaviour and viable disease intervention methods. Model analysis shows that elimination of S. scabiei in the wild is most sensitive to the success of treatment delivery, and duration of the programme. In addition, we found the frequency that wombats switch burrows was an important positive driver of mite persistence. Synthesis and applications . This research emphasizes the utility of applying model‐guided management techniques in order to achieve practical solutions for controlling disease in the field. We find that control efforts of Sarcoptes scabiei are most successful when simultaneous improvements are made to the current best‐practice protocol, specifically the implementation of better treatment application methods in combination with a longer lasting treatment. These suggested management changes may also reduce the resources and field effort required to implement a successful regime. Furthermore, our approach and findings have applicability to other species affected by S. scabiei (e.g. wolves, red foxes, Spanish ibex and American black bear), as well as other conservation‐critical systems involving environmental transmission (e.g. bat white‐nose syndrome and hibian chytridiomycosis).

University Of The Sunshine Coast

Location: Australia

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Queensland University Of Technology

Location: Australia

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Linkage Projects - Grant ID: LP120200051

Start Date: 07-2012

End Date: 12-2015

Amount: $465,000.00

Funder: Australian Research Council

Discovery Projects - Grant ID: DP150101485

Start Date: 2015

End Date: 02-2018

Amount: $458,600.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP140100315

Start Date: 07-2014

End Date: 07-2017

Amount: $509,100.00

Funder: Australian Research Council

Understanding The Origin, Epidemiology And Transmission Threat Of Chlamydial Infections Between Australian Native Animals And Livestock

Start Date: 2013

End Date: 2015

Funder: Australian Research Council

Project LP160100138

Start Date: 2016

End Date: 2018

Funder: Australian Research Council

Development Of A Safe And Immunogenic Anti-chlamydia Vaccine For The Koala

Start Date: 2012

End Date: 2015

Funder: Australian Research Council

Project DP150101485

Start Date: 2015

End Date: 2017

Funder: Australian Research Council

Project LP150100046

Start Date: 2015

End Date: 2018

Funder: Australian Research Council

Improving The Diagnosis, Management And Control Of Chlamydial Infections In Australian Livestock

Start Date: 2014

End Date: 2017

Funder: Australian Research Council

Linkage Infrastructure, Equipment And Facilities - Grant ID: LE170100192

Start Date: 05-2017

End Date: 12-2017

Amount: $450,000.00

Funder: Australian Research Council

Linkage Projects - Grant ID: LP160101599

Start Date: 03-2018

End Date: 10-2018

Amount: $293,000.00

Funder: Australian Research Council