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Little puppy lost
After he slips out of his collar, Harry the dog gets lost in the woods until a cat named Ginger comes to his rescue.
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Stable in vitro fluorescence for enhanced live imaging of infection models for Batrachochytrium dendrobatidis
Realistic and modifiable infection models are required to study the pathogenesis of amphibian chytridiomycosis. Understanding the mechanism by which
Batrachochytrium dendrobatidis
(Bd) can infect and kill diverse amphibians is key to mitigating this pathogen and preventing further loss of biodiversity.
In vitro
studies of Bd typically rely on a tryptone based growth media, whereas the recent development of a kidney cell-line infection model has provided a more realistic alternative, without the need for live animals. Here we use expression of a fluorescent reporter to enhance the
in vitro
cell-line based growth assay, and show that transformed Bd cells are able to invade and grow in an amphibian kidney epithelial cell line (A6) as well as in a new system using a lung fibroblast cell line (DWJ). Both Bd and host cells were modified to express reporter fluorescent proteins, enabling immediate and continuous observation of the infection process without the need for destructive sampling for fixation and staining. Plasmid DNA conferring hygromycin resistance and TdTomato (RFP) expression was delivered to Bd zoospores via electroporation, and continuous antibiotic selection after recovery produced stable fluorescent Bd transformants. Host cells (A6 and DWJ) were transfected before each assay using lipofection to deliver plasmid DNA conferring green fluorescent protein (GFP) and containing an empty shRNA expression cassette. Bd RFP expression allowed easy localisation of fungal cells and identification of endobiotic growth was assisted by host GFP expression, by allowing visualization of the space in the host cell occupied by the invading fungal body. In addition to enabling enhanced live imaging, these methods will facilitate future genetic modification and characterisation of specific genes and their effect on Bd virulence.
Journal Article
Recent Asian origin of chytrid fungi causing global amphibian declines
Species in the fungal genus
Batrachochytrium
are responsible for severe declines in the populations of amphibians globally. The sources of these pathogens have been uncertain. O'Hanlon
et al.
used genomics on a panel of more than 200 isolates to trace the source of the frog pathogen
B. dendrobatidis
to a hyperdiverse hotspot in the Korean peninsula (see the Perspective by Lips). Over the past century, the trade in amphibian species has accelerated, and now all lineages of
B. dendrobatidis
occur in traded amphibians; the fungus has become ubiquitous and is diversifying rapidly.
Science
, this issue p.
621
; see also p.
604
The chytrid fungus responsible for global amphibian declines originated in the Korean peninsula and spread during the past century by human trade.
Globalized infectious diseases are causing species declines worldwide, but their source often remains elusive. We used whole-genome sequencing to solve the spatiotemporal origins of the most devastating panzootic to date, caused by the fungus
Batrachochytrium dendrobatidis
, a proximate driver of global amphibian declines. We traced the source of
B. dendrobatidis
to the Korean peninsula, where one lineage,
Bd
ASIA-1, exhibits the genetic hallmarks of an ancestral population that seeded the panzootic. We date the emergence of this pathogen to the early 20th century, coinciding with the global expansion of commercial trade in amphibians, and we show that intercontinental transmission is ongoing. Our findings point to East Asia as a geographic hotspot for
B. dendrobatidis
biodiversity and the original source of these lineages that now parasitize amphibians worldwide.
Journal Article
Pregnancy related risk perception in pregnant women, midwives & doctors: a cross-sectional survey
Background
Risk perception in relation to pregnancy and birth is a complex process influenced by multiple personal, psychological and societal factors. Traditionally, the risk perception of healthcare professionals has been presented as more objective and authoritative than that of pregnant women. Doctors have been presented as more concerned with biomedical risk than midwives. Such dichotomies oversimplify and obscure the complexity of the process. This study examines pregnancy-related risk perception in women and healthcare professionals, and what women and professionals believe about each other’s risk perception.
Methods
A cross sectional survey of set in UK maternity services. Participants were doctors working in obstetrics (
N
= 53), midwives (
N
= 59), pregnant women (
N
= 68). Participants were recruited in person from two hospitals. Doctors were also recruited online. Participants completed a questionnaire measuring the degree of perceived risk in various childbirth-related scenarios; and the extent to which they believed others agreed with them about the degree of risk generally involved in childbirth. Main outcome measures were the degree of risk perceived to the mother in baby in pregnancy scenarios, and beliefs about own perception of risk in comparison to their own group and other groups.
Results
There were significant differences in total risk scores between pregnant women, doctors and midwives in perception of risk to the mother in 68/80 scenarios. Doctors most frequently rated risks lowest. Total scores for perceived risk to the baby were not significantly different. There was substantial variation within each group. There was more agreement on the ranking of scenarios according to risk. Each group believed doctors perceived most risk whereas actually doctors most frequently rated risks lowest. Each group incorrectly believed their peers rated risk similarly to themselves.
Conclusions
Individuals cannot assume others share their perception of risk or that they make correct assessments regarding others’ risk perception. Further research should consider what factors are taken into account when making risk assessments,
Journal Article
When birth is not as expected: a systematic review of the impact of a mismatch between expectations and experiences
Background
Pregnancy and childbirth are significant events in women’s lives and most women have expectations or plans for how they hope their labour and birth will go. It is possible that strong expectations about labour and birth lead to dissatisfaction or other negative outcomes if these expectations are not met, but it is not clear if this is the case. The aim was therefore to synthesise prospective studies in order to understand whether unmet birth expectations are associated with adverse outcomes for women, their partners and their infants.
Method
Searches were carried out in Academic Search Complete; CINAHL; Medline; PsycINFO, PsychArticles, PubMed, SCOPUS and Web of Science. Forward and backward searches were also completed. Studies were included if they reported prospective empirical research that examined the association between a mismatch in birth expectations/experience and postnatal outcomes in women, their children and/or their partners. Data were synthesised qualitatively using a narrative approach where study characteristics, context and methodological quality were extracted and summarised and then the differences and similarities among studies were used to draw conclusions.
Results
Eleven quantitative studies were identified for inclusion from nine countries. A mismatch between birth expectations and experiences was associated with reduced birth satisfaction. Three studies found a link between a mismatch and the development of postnatal post-traumatic stress disorder (PTSD). The evidence was inconsistent for postnatal depression, and fear of childbirth. Only one study looked at physical outcomes in the form of health-related quality of life.
Conclusions
A mismatch between birth expectations and experiences is associated with birth satisfaction and it may increase the risk of developing postnatal PTSD. However, it is not clear whether a mismatch is associated with other postnatal mental health conditions. Further prospective research is needed to examine gaps in knowledge and provide standardised methods of measuring childbirth expectations-experiences mismatch. To ensure women’s expectations are met, and therefore experience a satisfying birth experience, maternity providers should provide sensitive care, which acknowledges women’s needs and preferences, is based on open and clear communication, is delivered as early in pregnancy as possible, and enables women to make their own decisions about care.
Trial registration
Protocol registration:
PROSPERO
CRD42020191081
.
Journal Article
Declining amphibians might be evolving increased reproductive effort in the face of devastating disease
The devastating infectious disease chytridiomycosis has caused declines of amphibians 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 individual level, and population-level disease exposure can result in changes to baseline reproductive effort; therefore, individual- and population-level effects of disease should be considered when designing management and conservation programs for threatened and declining species.
Journal Article
Pathogenesis of Chytridiomycosis, a Cause of Catastrophic Amphibian Declines
The pathogen Batrachochytrium dendrobatidis (Bd), which causes the skin disease chytridiomycosis, is one of the few highly virulent fungi in vertebrates and has been implicated in worldwide amphibian declines. However, the mechanism by which Bd causes death has not been determined. We show that Bd infection is associated with pathophysiological changes that lead to mortality in green tree frogs (Litoria caerulea). In diseased individuals, electrolyte transport across the epidermis was inhibited by >50%, plasma sodium and potassium concentrations were respectively reduced by approximately 20% and approximately 50%, and asystolic cardiac arrest resulted in death. Because the skin is critical in maintaining amphibian homeostasis, disruption to cutaneous function may be the mechanism by which Bd produces morbidity and mortality across a wide range of phylogenetically distant amphibian taxa.
Journal Article
The Binding, Infection, and Promoted Growth of Batrachochytrium dendrobatidis by the Ranavirus FV3
Increasing reports suggest the occurrence of co-infection between Ranaviruses such as Frog Virus 3 (FV3) and the chytrid fungus Batrachochytrium dendrobatidis (Bd) in various amphibian species. However, the potential direct interaction of these two pathogens has not been examined to date. In this study, we investigated whether FV3 can interact with Bd in vitro using qPCR, conventional microscopy, and immunofluorescent microscopy. Our results reveal the unexpected ability of FV3 to bind, promote aggregation, productively infect, and significantly increase Bd growth in vitro. To extend these results in vivo, we assessed the impact of FV3 on Xenopus tropicalis frogs previously infected with Bd. Consistent with in vitro results, FV3 exposure to previously Bd-infected X. tropicalis significantly increased Bd loads and decreased the host’s survival.
Journal Article
Meta-review of the barriers and facilitators to women accessing perinatal mental healthcare
Perinatal mental health (PMH) problems are common and can have an adverse impact on women and their families. However, research suggests that a substantial proportion of women with PMH problems do not access care.ObjectivesTo synthesise the results from previous systematic reviews of barriers and facilitators to women to seeking help, accessing help, and engaging in PMH care, and to suggest recommendations for clinical practice and policy.DesignA meta-review of systematic reviews.Review methodsSeven databases were searched and reviewed using a Preferred Reporting Items for Systematic Reviews and Meta Analyses search strategy. Studies that focused on the views of women seeking help and accessing PMH care were included. Data were analysed using thematic synthesis. Assessing the Methodological Quality of Systematic Reviews-2 was used to assess review methodology. To improve validity of results, a qualitative sensitivity analysis was conducted to assess whether themes remained consistent across all reviews, regardless of their quality rating.ResultsA total of 32 reviews were included. A wide range of barriers and facilitators to women accessing PMH care were identified. These mapped across a multilevel model of influential factors (individual, healthcare professional, interpersonal, organisational, political and societal) and across the care pathway (from decision to consult to receiving care). Evidence-based recommendations to support the design and delivery of PMH care were produced based on identified barriers and facilitators.ConclusionThe identified barriers and facilitators point to a complex interplay of many factors, highlighting the need for an international effort to increase awareness of PMH problems, reduce mental health stigma, and provide woman-centred, flexible care, delivered by well trained and culturally sensitive primary care, maternity, and psychiatric health professionals.PROSPERO registration numberCRD42019142854.
Journal Article
Climate Change Could Increase the Geographic Extent of Hendra Virus Spillover Risk
Disease risk mapping is important for predicting and mitigating impacts of bat-borne viruses, including Hendra virus (Paramyxoviridae:Henipavirus), that can spillover to domestic animals and thence to humans. We produced two models to estimate areas at potential risk of HeV spillover explained by the climatic suitability for its flying fox reservoir hosts, Pteropus alecto and P. conspicillatus. We included additional climatic variables that might affect spillover risk through other biological processes (such as bat or horse behaviour, plant phenology and bat foraging habitat). Models were fit with a Poisson point process model and a log-Gaussian Cox process. In response to climate change, risk expanded southwards due to an expansion of P. alecto suitable habitat, which increased the number of horses at risk by 175–260% (110,000–165,000). In the northern limits of the current distribution, spillover risk was highly uncertain because of model extrapolation to novel climatic conditions. The extent of areas at risk of spillover from P. conspicillatus was predicted shrink. Due to a likely expansion of P. alecto into these areas, it could replace P. conspicillatus as the main HeV reservoir. We recommend: (1) HeV monitoring in bats, (2) enhancing HeV prevention in horses in areas predicted to be at risk, (3) investigate and develop mitigation strategies for areas that could experience reservoir host replacements.
Journal Article