In situ hybridisation detects pro-apoptotic gene expression of a Bcl-2 family member in white syndrome-affected coral

White syndrome has been described as one of the most prolific diseases on the Great Barrier Reef. Previously, apoptotic cell death has been described as the mechanism driving the characteristic rapid tissue loss associated with this disease, but the molecular mechanisms controlling apoptotic cell death in coral disease have yet to be investigated. In situ methods were used to study the expression patterns of 2 distinct regulators of apoptosis in Acropora hyacinthus tissues undergoing white syndrome and apoptotic cell death. Apoptotic genes within the Bcl-2 family were not localized in apparently healthy coral tissues. However, a Bcl-2 family member (bax-like) was found to localize to cells and tissues affected by white syndrome and those with morphological evidence for apoptosis. A potential up-regulation of pro-apoptotic or bax-like gene expression in tissues with apoptotic cell death adjacent to disease lesions is consistent with apoptosis being the primary cause of rapid tissue loss in coral affected by white syndrome. Pro-apoptotic (bax-like) expression in desmocytes and the basal tissue layer, the calicodermis, distant from the disease lesion suggests that apoptosis may also underlie the sloughing of healthy tissues associated with the characteristic, rapid spread of tissue loss, evident of this disease. This study also shows that in situ hybridisation is an effective tool for studying gene expression in adult corals, and wider application of these methods should allow a better understanding of many aspects of coral biology and disease pathology

Who rescues who? Understanding aquatic rescues in Australia using coronial data and a survey

Objective: To examine fatal drowning associated with aquatic rescues and prior self‐reported experience of undertaking an aquatic rescue in Australia. Methods: Previous aquatic rescue experience was sourced through the 2013 Queensland Computer Assisted Telephone Instrument Survey and compared to data on rescue‐related fatal unintentional drowning between 1 January 2006 and 31 December 2015. Results: Twenty‐three per cent (n=294/1291) of survey respondents had previously performed an aquatic rescue. Males (X2=35.2; p<0.001) were more likely to have performed a rescue; commonly at a beach/ocean/harbour location (X2=13.5; p<0.001). Females were more likely to have rescued a child (0‐4 years of age) (X2=29.2; p<0.001) from a swimming pool (X2=34.3; p<0.001). Fifty‐one people drowned while performing an aquatic rescue (Males=82.4%; 25–44 years of age=53.0%; beaches=54.9%). Conclusions: Drownings are prevented by bystanders; this is not without risk to the rescuer. Most people perform only one rescue in their life, often at a younger age, on an altruistic basis, of family members or young children. Community‐wide rescue skills, taught at a young age, with consideration for coastal, inland and swimming pool environments, may prevent drowning

PROBE: preparedness and response - online bioterrorism education: foundation knowledge training

Terrorism and the resulting geo-political state of affairs have created a need for health professionals to be well prepared for bioterror. In our socio-political climate we need a rational approach to managing public perceptions and need to be able to lead an appropriate response to suspected bioterror events. This website was created as a resource for public health professionals interested in learning how to be more effective at preparing for and responding to a terrorist attack using bioweapons. Who is involved: The Anton Breinl Centre for Public Health and Tropical Medicine (ABC) at James Cook University, has particular expertise in disaster/emergency management, biological agents that constitute the greatest threat, and the sociology of terror. The ABC was the first institution in Australia to develop a bioterrorism course. What is PROBE? The PROBE (Preparedness & Response - Online Bioterrorism Education) project designs and develops multimedia-based, interactive decision support simulation modules for training and support of health professionals in the management of bioterrorism events in an Australian context. PROBE modules provide knowledge and experience that to enhance ability to make timely and appropriate decisions to management of bioterrorism events. In the foundation chapters, students develop an awareness of the increased focus and attention on bioterrorism research and preparedness and explore the implications for the public health sector

High flow conditions mediate damaging impacts of sub-lethal thermal stress on corals' endosymbiotic algae

The effects of thermal anomalies on tropical coral endosymbiosis can be mediated by a range of environmental factors, which in turn ultimately influence coral health and survival. One such factor is the water flow conditions over coral reefs and corals. Although the physiological benefits of living under high water flow are well known, there remains a lack of conclusive experimental evidence characterizing how flow mitigates thermal stress responses in corals. Here we use in situ measurements of flow in a variety of reef habitats to constrain the importance of flow speeds on the endosymbiosis of an important reef building species under different thermal regimes. Under high flow speeds (0.15 m s−1) and thermal stress, coral endosymbionts retained photosynthetic function and recovery capacity for longer compared to low flow conditions (0.03 m s−1). We hypothesize that this may be due to increased rates of mass transfer of key metabolites under higher flow, putatively allowing corals to maintain photosynthetic efficiency for longer. We also identified a positive interactive effect between high flow and a pre-stress, sub-lethal pulse in temperature. While higher flow may delay the onset of photosynthetic stress, it does not appear to confer long-term protection; sustained exposure to thermal stress (eDHW accumulation equivalent to 4.9°C weeks) eventually overwhelmed the coral meta-organism as evidenced by eventual declines in photo-physiological function and endosymbiont densities. Investigating flow patterns at the scale of metres within the context of these physiological impacts can reveal interesting avenues for coral reef management. This study increases our understanding of the effects of water flow on coral reef health in an era of climate change and highlights the potential to learn from existing beneficial bio-physical interactions for the effective preservation of coral reefs into the future

Adaptation of travel medicine practitioners to the COVID-19 pandemic: a cross-sectional survey of ISTM members

[Extract] The global pandemic of coronavirus disease 2019 (COVID-19) has severely compromised international travel and the practice of travel medicine. Uncertainty surrounds new procedures for travel and high levels of public anxiety around travelling are evident, especially with the emergence of further COVID-19 variants.1,2 Although there have been some insightful reflections in the recent literature,3–5 the impact on and the response of the travel medicine community to this pandemic have not been formally evaluated. The International Society of Travel Medicine (ISTM) represents the largest group of travel healthcare professionals. Our study aimed to evaluate the attitudes and adaptations of current ISTM members in relation to the disruption caused by the COVID-19 pandemic. The specific objectives of the study were to ascertain the extent to which members’ clinical practice has been affected by the pandemic and inform the Society’s strategic planning for upcoming activities and member engagement during the pandemic and early post-pandemic period

The effect of thermal history on the susceptibility of reef-building corals to thermal stress

The mutualistic relationship between corals and their unicellular dinoflagellate symbionts (Symbiodinium sp.) is a fundamental component within the ecology of coral reefs. Thermal stress causes the breakdown of the relationship between corals and their symbionts (bleaching). As with other organisms, this symbiosis may acclimate to changes in the environment, thereby potentially modifying the environmental threshold at which they bleach. While a few studies have examined the acclimation capacity of reef-building corals, our understanding of the underlying mechanism is still in its infancy. The present study focused on the role of recent thermal history in influencing the response of both corals and symbionts to thermal stress, using the reef-building coral Acropora aspera. The symbionts of corals that were exposed to 31 degrees C for 48 h (pre-stress treatment) 1 or 2 weeks prior to a 6-day simulated bleaching event (when corals were exposed to 34 degrees C) were found to have more effective photoprotective mechanisms. These mechanisms included changes in non-photochemical quenching and xanthophyll cycling. These differences in photoprotection were correlated with decreased loss of symbionts, with those corals that were not prestressed performing significantly worse, losing over 40% of their symbionts and having a greater reduction in photosynthetic efficiency. These results are important in that they show that thermal history, in addition to light history, can influence the response of reef-building corals to thermal stress and therefore have implications for the modeling of bleaching events. However, whether acclimation is capable of modifying the thermal threshold of corals sufficiently to cope as sea temperatures increase in response to global warming has not been fully explored. Clearly increases in sea temperatures that extend beyond 1-2 degrees C will exhaust the extent to which acclimation can modify the thermal threshold of corals

Transcriptomic Analysis of Thermally Stressed Symbiodinium Reveals Differential Expression of Stress and Metabolism Genes

Endosymbioses between dinoflagellate algae (Symbiodinium sp.) and scleractinian coral species form the foundation of coral reef ecosystems. The coral symbiosis is highly susceptible to elevated temperatures, resulting in coral bleaching, where the algal symbiont is released from host cells. This experiment aimed to determine the transcriptional changes in cultured Symbiodinium, to better understand the response of cellular mechanisms under future temperature conditions. Cultures were exposed to elevated temperatures (average 31°C) or control conditions (24.5°C) for a period of 28 days. Whole transcriptome sequencing of Symbiodinium cells on days 4, 19, and 28 were used to identify differentially expressed genes under thermal stress. A large number of genes representing 37.01% of the transcriptome (∼23,654 unique genes, FDR < 0.05) with differential expression were detected at no less than one of the time points. Consistent with previous studies of Symbiodinium gene expression, fold changes across the transcriptome were low, with 92.49% differentially expressed genes at ≤2-fold change. The transcriptional response included differential expression of genes encoding stress response components such as the antioxidant network and molecular chaperones, cellular components such as core photosynthesis machinery, integral light-harvesting protein complexes and enzymes such as fatty acid desaturases. Differential expression of genes encoding glyoxylate cycle enzymes were also found, representing the first report of this in Symbiodinium. As photosynthate transfer from Symbiodinium to coral hosts provides up to 90% of a coral's daily energy requirements, the implications of altered metabolic processes from exposure to thermal stress found in this study on coral-Symbiodinium associations are unknown and should be considered when assessing the stability of the symbiotic relationship under future climate conditions.This study was supported by the Australian Research Council Centre of Excellence for Coral Reef Studies (CE140100020) and Australian Research Council Discovery Projects (DP130101421 and DP160100271)

The characteristics of drowning among different types of international visitors to Australia and how this contributes to their drowning risk

Objective: Australia is a popular destination for international visitors. This study reviews international visitor drowning deaths in Australia and analyses drowning by visitor type. Methods: A total population retrospective study exploring drowning deaths of international visitors was conducted between 2008 and 2018. Data were extracted from the Royal Life Saving National Fatal Drowning Database and categorised into four subgroups: overseas tourists, international students, working holiday makers and work-related visitors. Descriptive statistics, non-parametric tests and relative risk (RR) were calculated. Results: In total, 201 international visitors drowned in Australia, 7% of all drowning deaths; a crude drowning rate of 0.27/100,000 visitors versus 0.95/100,000 for residents (RR=0.19 [95% CI: 0.16–0.22]). Most deaths were males (79%) and people aged 18–34 years (50%). Visitors frequently drowned at beaches (33%), and when swimming (41%). Thirty-five percent recorded a pre-existing medical condition. Overseas tourists on holiday were the most likely to drown compared to other subgroups. Conclusion: International visitors represent a small but increasing proportion of people drowning in Australia. The circumstances of which visitors drown vary by travel purpose, age, country of origin, location of drowning and activity. Implications for public health: International visitors have unique safety needs, requiring tailored prevention based on the purpose of travel and country of origin

In situ hybridisation detects pro-apoptotic gene expression of a Bcl-2 family member in white syndrome-affected coral

White syndrome has been described as one of the most prolific diseases on the Great Barrier Reef. Previously, apoptotic cell death has been described as the mechanism driving the characteristic rapid tissue loss associated with this disease, but the molecular mechanisms controlling apoptotic cell death in coral disease have yet to be investigated. In situ methods were used to study the expression patterns of 2 distinct regulators of apoptosis in Acropora hyacinthus tissues undergoing white syndrome and apoptotic cell death. Apoptotic genes within the Bcl-2 family were not localized in apparently healthy coral tissues. However, a Bcl-2 family member (bax-like) was found to localize to cells and tissues affected by white syndrome and those with morphological evidence for apoptosis. A potential up-regulation of pro-apoptotic or bax-like gene expression in tissues with apoptotic cell death adjacent to disease lesions is consistent with apoptosis being the primary cause of rapid tissue loss in coral affected by white syndrome. Pro-apoptotic (bax-like) expression in desmocytes and the basal tissue layer, the calicodermis, distant from the disease lesion suggests that apoptosis may also underlie the sloughing of healthy tissues associated with the characteristic, rapid spread of tissue loss, evident of this disease. This study also shows that in situ hybridisation is an effective tool for studying gene expression in adult corals, and wider application of these methods should allow a better understanding of many aspects of coral biology and disease pathology

Photoreactivation is the main repair pathway for UV-induced DNA damage in coral planulae

The larvae of most coral species spend some time in the plankton, floating just below the surface and hence exposed to high levels of ultraviolet radiation (UVR). The high levels of UVR are potentially stressful and damaging to DNA and other cellular components, such as proteins, reducing survivorship. Consequently, mechanisms to either shade (prevent) or repair damage potentially play an important role. In this study, the role of photoreactivation in the survival of coral planulae was examined. Photoreactivation is a light-stimulated response to UV-damaged DNA in which photolyase proteins repair damaged DNA. Photoreactivation rates, as well as the localization of photolyase, were explored in planulae under conditions where photoreactivation was or was not inhibited. The results indicate that photoreactivation is the main DNA repair pathway in coral planulae, repairing UV-induced DNA damage swiftly (K=1.75 h–1 and a half-life of repair of 23 min), with no evidence of any light-independent DNA repair mechanisms, such as nucleotide excision repair (NER), at work. Photolyase mRNA was localized to both the ectoderm and endoderm of the larvae. The amount of cell death in the coral planulae increased significantly when photoreactivation was inhibited, by blocking photoreactivating light. We found that photoreactivation, along with additional UV shielding in the form of five mycosporine-like amino acids, are sufficient for survival in surface tropical waters and that planulae do not accumulate DNA damage despite being exposed to high UVR