ORCID Profile
0000-0002-8571-4453
Current Organisations
University of Melbourne
,
James Cook University
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Publisher: Wiley
Date: 03-06-2019
DOI: 10.1002/FEE.2057
Publisher: Elsevier BV
Date: 12-2017
DOI: 10.1016/J.DCI.2017.08.018
Abstract: Temperature variability, and in particular temperature decreases, can increase susceptibility of hibians to infections by the fungus Batrachochytrium dendrobatidis (Bd). However, the effects of temperature shifts on the immune systems of Bd-infected hibians are unresolved. We acclimated frogs to 16 °C and 26 °C (baseline), simultaneously transferred them to an intermediate temperature (21 °C) and inoculated them with Bd (treatment), and tracked their infection levels and white blood cell profiles over six weeks. Average weekly infection loads were consistently higher in 26°C-history frogs, a group that experienced a 5 °C temperature decrease, than in 16°C-history frogs, a group that experienced a 5 °C temperature increase, but this pattern only approached statistical significance. The 16°C-acclimated frogs had high neutrophil:lymphocyte (N:L) ratios (suggestive of a hematopoietic stress response) at baseline, which were conserved post-treatment. In contrast, the 26°C-acclimated frogs had low N:L ratios at baseline which reversed to high N:L ratios post-treatment (suggestive of immune system activation). Our results suggest that infections were less physiologically taxing for the 16°C-history frogs than the 26°C-history frogs because they had already adjusted immune parameters in response to challenging conditions (cold). Our findings provide a possible mechanistic explanation for observations that hibians are more susceptible to Bd infection following temperature decreases compared to increases and underscore the consensus that increased temperature variability associated with climate change may increase the impact of infectious diseases.
Publisher: Wiley
Date: 20-12-2018
DOI: 10.1111/AEC.12695
Publisher: Oxford University Press (OUP)
Date: 16-03-2018
DOI: 10.1093/MMY/MYY010
Abstract: Captive and wild hibians are under threat of extinction from the deadly fungal pathogen Batrachochytrium dendrobatidis (Bd). The antifungal drug terbinafine (TBF) is used by pet owners to treat Bd-infected frogs however, it is not widely used in academic or zoological institutions due to limited veterinary clinical trials. To assess TBF's efficacy, we undertook treatment trials and pharmacokinetic studies to investigate drug absorption and persistence in frog skin and then we correlated these data to the minimal lethal concentrations (MLC) against Bd. Despite an initial reduction in zoospore load, the recommended treatment (five daily 5 min 0.01% TBF baths) was unable to cure experimentally infected alpine tree frogs and naturally infected common eastern froglets. In vitro and in vivo pharmacokinetics showed that absorbed TBF accumulates in frog skin with increased exposure, indicating its suitability for treating cutaneous pathogens via direct application. The MLC of TBF for zoosporangia was 100 μg/ml for 2 h, while the minimal inhibitory concentration was 2 μg/ml, suggesting that the drug concentration absorbed during 5 min treatments is not sufficient to cure high Bd burdens. With longer treatments of five daily 30 min baths, Bd clearance improved from 12.5% to 50%. A higher dose of 0.02% TBF resulted in 78% of animals cured however, clearance was not achieved in all in iduals due to low TBF skin persistence, as the half-life was less than 2 h. Therefore, the current TBF regime is not recommended as a universal treatment against Bd until protocols are optimized, such as with increased exposure frequency.
Publisher: Wiley
Date: 24-08-2021
DOI: 10.1111/EVO.14327
Abstract: The devastating infectious disease chytridiomycosis has caused declines of hibians across the globe, yet some populations are persisting and even recovering. One understudied effect of wildlife disease is changes in reproductive effort. Here, we aimed to understand if the disease has plastic effects on reproduction and if reproductive effort could evolve with disease endemism. We compared the effects of experimental pathogen exposure (trait plasticity) and population-level disease history (evolution in trait baseline) on reproductive effort using gametogenesis as a proxy in the declining and endangered frog Litoria verreauxii alpina. We found that unexposed males from disease-endemic populations had higher reproductive effort, which is consistent with an evolutionary response to chytridiomycosis. We also found evidence of trait plasticity, where males and females were affected differently by infection: pathogen exposed males had higher reproductive effort (larger testes), whereas females had reduced reproductive effort (smaller and fewer developed eggs) regardless of the population of origin. Infectious diseases can cause plastic changes in the reproductive effort at an in idual level, and population-level disease exposure can result in changes to baseline reproductive effort therefore, in idual- and population-level effects of disease should be considered when designing management and conservation programs for threatened and declining species.
Publisher: Inter-Research Science Center
Date: 13-06-2012
DOI: 10.3354/DAO02461
Abstract: Chytridiomycosis in hibians, and mucormycosis in the platypus Ornithorhynchus anatinus and hibians, are serious fungal diseases affecting these aquatic taxa. In Tasmania, Australia, the fungi that cause these diseases overlap in range along with Phytophthora cinnamomi (Pc), an invasive fungal plant pathogen. To identify disinfectants that may be useful to reduce anthropogenic spread of these fungi to uninfected wilderness areas, for ex le by bush walkers and forestry or fire-fighting operations, we tested 3 disinfectants and a fire-fighting foam against Mucor hibiorum (Ma) and tested 1 disinfectant and the foam against Batrachochytrium dendrobatidis (Bd). Combining the present study with previous work we found Bd was more susceptible to all 4 chemicals than Ma. Phytoclean, a disinfectant used at 2 to 10% for 30 s to control Pc, killed cultures of Bd at 0.075% and Ma at 5%, when also applied for 30 s. The disinfectant F10sc was not effective against Ma at standard exposures, but previous work shows Bd is killed at 0.03% with a 1 min exposure. Path-X is effective against Bd at 0.001% with a 30 s exposure and killed Ma at 1% with a 5 min exposure. Forexpan S, a foam added to water at 0.1 to 1% to control forest fires, killed Bd but not Ma when used at 1% for 2 min. Therefore, Phytoclean and Path-X have broader efficacy, although Path-X has not been trialled against Pc. Interestingly a positive mating strain of Ma (from a platypus) was more resistant to disinfectants than a negative strain (from a frog). Current protocols against Pc that involve high concentrations (10%) of Phytoclean are likely to reduce spread of pathogenic wildlife fungi, which is important for protecting bio ersity.
Publisher: Informa UK Limited
Date: 09-10-2023
Publisher: Hindawi Limited
Date: 13-08-2019
DOI: 10.1111/CMI.13089
Abstract: Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd), is a skin disease responsible for the global decline of hibians. Frog species and populations can vary in susceptibility, but this phenomenon remains poorly understood. Here, we investigated serotonin in the skin of infected and uninfected frogs. In more susceptible frog populations, skin serotonin rose with increasing infection intensity, but decreased in later stages of the disease. The more resistant population maintained a basal level of skin serotonin. Serotonin inhibited both Bd sporangial growth and Jurkat lymphocyte proliferation in vitro. However, serotonin accumulates in skin granular glands, and this compartmentalisation may prevent inhibition of Bd growth in vivo. We suggest that skin serotonin increases in susceptible frogs due to pathogen excretion of precursor tryptophan, but that resistant frogs are able to control the levels of serotonin. Overall, the immunosuppressive effects of serotonin may contribute to the susceptibility of frogs to chytridiomycosis.
Publisher: Wiley
Date: 03-09-2023
Publisher: Informa UK Limited
Date: 17-12-2022
DOI: 10.1080/09638288.2021.2012843
Abstract: People with communication disability after stroke need interventions to optimise healthcare communication and rehabilitation outcomes. Current evidence syntheses do not adequately inform the management of communication disability during the first 90 days post-stroke. To explore the scope of literature for the management of communication disability in the first 90 days after stroke. A scoping review was conducted using a systematic keyword search of six databases. A descriptive synthesis was generated using communication-related domains related to the biopsychosocial framework of the International Classification of Functioning, Disability, and Health (ICF). A total of 129 studies met eligibility criteria. Aphasia was the most frequently addressed communication disability after stroke (76/129 studies) with a paucity of evidence investigating other acquired neurogenic communication impairments. Management predominantly focused on communication-related: body functions and structures (62 studies) (e.g., linguistic-behavioural therapies), followed by environmental factors (39 studies) (e.g., communication partner training/support) activities and participation (15 studies) (e.g., augmentative and alternative communication) and personal factors (13 studies) (e.g., assessment of depression after aphasia). A coordinated, integrated approach to developing and testing acute and subacute interventions for all communication disabilities across all communication-related domains is required.IMPLICATIONS FOR REHABILITATIONInterdisciplinary stroke clinicians need to manage communication disabilities in the first 90 days after stroke to optimise healthcare communication and rehabilitation outcomes.There is some evidence to guide clinicians in aphasia management but less in other disabilities of speech and cognitive functioning.Most interventions to inform clinical practice address communication-related body functions and structures (e.g., linguistic and speech therapies). Clinicians need to address all domains and more evidence is needed to address environmental factors (e.g., communication support) activities and participation (e.g., person-centred goal setting) and personal factors (e.g., psychological care).
Publisher: Wiley
Date: 14-08-2017
Publisher: Informa UK Limited
Date: 09-10-2022
DOI: 10.1080/09638288.2021.1971307
Abstract: Community aphasia groups (CAGs) can provide a range of benefits to people with aphasia and support long-term psychosocial wellbeing. However, the dominant speech-pathologist-led service delivery model is inherently limited in scope. Peer-led groups hold potential as a sustainable and empowering extension of this traditional model. The implementation of peer-led models likely requires targeted training and support, however little is known about the characteristics and impacts of CAG facilitation. This study reviews the literature on CAGs and their facilitation. We conducted a scoping review on this topic. One hundred and seventy-seven texts were included, reporting on a heterogeneous range of activities. Most texts reported on speech-pathologist-led groups, however, a range of alternative models were also represented. While no studies directly compared the impacts of different facilitation models, some comparative benefits could be drawn from the literature. Facilitation was perceived as complex and challenging, and significant gaps were identified in the training of facilitators. Ten qualitative studies investigated characteristics and impacts of facilitator behaviours, providing a useful foundation for future development of training and evaluation tools. Further investigation into alternative facilitation models and facilitator training needs will likely support the proliferation of high-quality CAGs.Implications for RehabilitationCommunity aphasia groups (CAGs) play an important role in supporting identity and wellbeing for in iduals with chronic aphasia.The traditional speech-pathology led model of group service delivery is limited in scope the addition of peer- and volunteer-led CAGs may facilitate access to groups and meet a range of different needs for in iduals with aphasia.CAG facilitation is a complex and challenging task, likely requiring specialised training, however, this has not been widely available to facilitators.The development of specialised facilitator training will likely support the proliferation of sustainable and high-quality CAGs.
No related grants have been discovered for Lucette Lanyon.