Archival mitogenomes identify invasion by the Batrachochytrium dendrobatidis CAPE lineage caused an African amphibian extinction in the wild.

Outbreaks of emerging infectious diseases are influenced by local biotic and abiotic factors, with host declines occurring when conditions favour the pathogen. Deterioration in the population of the micro-endemic Tanzanian Kihansi spray toad (Nectophrynoides asperginis) occurred after the construction of a hydropower dam, implicating habitat modification in this species decline. Population recovery followed habitat augmentation; however, a subsequent outbreak of chytridiomycosis caused by Batrachochytrium dendrobatidis (Bd) led to the spray toad's extinction in the wild. We show using spatiotemporal surveillance and mitogenome assembly of Bd from archived toad mortalities that the outbreak was caused by invasion of the BdCAPE lineage and not the panzootic lineage BdGPL. Molecular dating reveals an emergence of BdCAPE across southern Africa overlapping with the timing of the spray toad's extinction. That our post-outbreak surveillance of co-occurring amphibian species in the Udzungwa Mountains shows widespread infection by BdCAPE yet no signs of ill-health or decline suggests these other species can tolerate Bd when environments are stable. We conclude that, despite transient success in mitigating the impact caused by dams' construction, invasion by BdCAPE caused the ultimate die-off that led to the extinction of the Kihansi spray toad.

Applying machine learning to international drug monitoring: classifying cannabis resin collected in Europe using cannabinoid concentrations.

In Europe, concentrations of ∆9-tetrahydrocannabinol (THC) in cannabis resin (also known as hash) have risen markedly in the past decade, potentially increasing risks of mental health disorders. Current approaches to international drug monitoring cannot distinguish between different types of cannabis resin which may have contrasting health effects due to THC and cannabidiol (CBD) content. Here, we compared concentrations of THC and CBD in different types of cannabis resin collected in Europe (either Moroccan-type, or Dutch-type). We then tested the ability of machine learning algorithms to classify the type of cannabis resin (either Moroccan-type, or Dutch-type) using routinely collected monitoring data on THC and CBD. Finally, we applied the optimal algorithm to new samples collected in countries where the type of cannabis resin was unknown, the UK and Denmark. Results showed that overall, Dutch-type samples had higher THC (Hedges' g = 2.39) and lower CBD (Hedges' g = 0.81) than Moroccan-type samples. A Support Vector Machine algorithm achieved classification accuracy exceeding 95%, with little variation in this estimate, good interpretability, and plausibility. It made contrasting predictions about the type of cannabis resin collected in the UK (94% Moroccan-type; 6% Dutch-type) and Denmark (36% Moroccan-type; 64% Dutch-type). In conclusion, we provide proof-of-concept evidence for the potential of machine learning to inform international drug monitoring. Our findings should not be interpreted as objective confirmatory evidence but suggest that Dutch-type cannabis resin has higher THC concentrations than Moroccan-type cannabis resin, which may contribute to variation in drug markets and health outcomes for people who use cannabis in Europe.

Ineffective responses to unlikely outbreaks: Hypothesis building in newly-emerging infectious disease outbreaks.

Over the last 30 years, there has been significant investment in research and infrastructure aimed at mitigating the threat of newly emerging infectious diseases (NEID). Core epidemiological processes, such as outbreak investigations, however, have received little attention and have proceeded largely unchecked and unimproved. Using ethnographic material from an investigation into a cryptic encephalitis outbreak in the Brong-Ahafo Region of Ghana in 2010-2013, in this paper we trace processes of hypothesis building and their relationship to the organizational structures of the response. We demonstrate how commonly recurring features of NEID investigations produce selective pressures in hypothesis building that favor iterations of pre-existing "exciting" hypotheses and inhibit the pursuit of alternative hypotheses, regardless of relative likelihood. These findings contribute to the growing anthropological and science and technology studies (STS) literature on the epistemic communities that coalesce around suspected NEID outbreaks and highlight an urgent need for greater scrutiny of core epidemiological processes.

Synthesis and Stereochemical Determination of the Peptide Antibiotic Novo29.

This paper describes the synthesis and stereochemical determination of Novo29 (clovibactin), a new peptide antibiotic that is related to teixobactin and is active against Gram-positive bacteria. Novo29 is an eight-residue depsipeptide that contains the noncanonical amino acid hydroxyasparagine of hitherto undetermined stereochemistry in a macrolactone ring. The amino acid building blocks Fmoc-(2R,3R)-hydroxyasparagine-OH and Fmoc-(2R,3S)-hydroxyasparagine-OH were synthesized from (R,R)- and (S,S)-diethyl tartrate. Novo29 and epi-Novo29 were then prepared by solid-phase peptide synthesis using these building blocks. Correlation with an authentic sample of Novo29 through 1H NMR spectroscopy, LC-MS, and in vitro antibiotic activity established that Novo29 contains (2R,3R)-hydroxyasparagine. X-ray crystallography reveals that epi-Novo29 adopts an amphiphilic conformation, with a hydrophobic surface and a hydrophilic surface. Four sets of epi-Novo29 molecules pack in the crystal lattice to form a hydrophobic core. The macrolactone ring adopts a conformation in which the main-chain amide NH groups converge to create a cavity, which binds ordered water and acetate anion. The amphiphilic conformation of epi-Novo29 is reminiscent of the amphiphilic conformation adopted by the related antibiotic teixobactin and its derivatives, which contains a hydrophobic surface that interacts with the lipids of the bacterial cell membrane and a hydrophilic surface that interacts with the aqueous environment. Molecular modeling suggests that Novo29 can adopt an amphiphilic conformation similar to teixobactin, suggesting that Novo29 may interact with bacteria in a similar fashion to teixobactin.

Interpopulation differences in male reproductive effort drive the population dynamics of a host exposed to an emerging fungal pathogen.

Compensatory recruitment is a key demographic mechanism that has allowed the coexistence of populations of susceptible amphibians with Batrachochytrium dendrobatidis (Bd), a fungus causing one of the most devastating emerging infectious disease ever recorded among vertebrates. However, the underlying processes (e.g. density-dependent increase in survival at early life stages, change in reproductive traits) as well as the level of interpopulation variation in this response are poorly known. We explore potential mechanisms of compensatory recruitment in response to Bd infection by taking advantage of an amphibian system where male reproductive traits are easy to quantify in free-living populations. The Southern Darwin's frog Rhinoderma darwinii is a vocal sac-brooding species that exhibits a high susceptibility to lethal Bd infection. Using a 7-year capture-recapture study at four populations with contrasting Bd infection status (one high prevalence, one low prevalence and two Bd-free populations), we evaluated whether Bd-positive populations exhibited a higher adult recruitment and a higher male reproductive effort than Bd-negative populations. We also estimated population growth rates to explore whether recruitment compensated for the negative impacts of Bd on the survival of adults. In addition, we evaluated a potential demographic signal of compensatory recruitment (i.e. positive relationship between the proportion of juveniles and Bd prevalence) in response to Bd infection using raw count data from 13 R. darwinii populations. The high Bd prevalence population exhibited the highest male reproductive effort and the highest recruitment among the four monitored populations. This led to a growing population during the study period despite high mortality of adult hosts. In contrast, males from the population with low Bd prevalence had a low reproductive effort and this population, which had the lowest adult recruitment, was declining during the study period despite adults having a higher survival in comparison to the high Bd prevalence population. We also found a demographic signal of compensatory recruitment in response to Bd infection in our broader analysis of 13 R. darwinii populations. Our study underlines the importance of interpopulation variation in life-history strategies on the fate of host populations after infectious disease emergence. Our results also suggest that an increase in reproductive effort can be one of the processes underlying compensatory recruitment in populations of Bd-susceptible amphibians.

Why disease ecology needs life-history theory: a host perspective.

When facing an emerging infectious disease of conservation concern, we often have little information on the nature of the host-parasite interaction to inform management decisions. However, it is becoming increasingly clear that the life-history strategies of host species can be predictive of individual- and population-level responses to infectious disease, even without detailed knowledge on the specifics of the host-parasite interaction. Here, we argue that a deeper integration of life-history theory into disease ecology is timely and necessary to improve our capacity to understand, predict and mitigate the impact of endemic and emerging infectious diseases in wild populations. Using wild vertebrates as an example, we show that host life-history characteristics influence host responses to parasitism at different levels of organisation, from individuals to communities. We also highlight knowledge gaps and future directions for the study of life-history and host responses to parasitism. We conclude by illustrating how this theoretical insight can inform the monitoring and control of infectious diseases in wildlife.

Difficult intravenous access in the emergency department: Performance and impact of ultrasound-guided IV insertion performed by nurses.

BACKGROUND: Difficult intravenous access (DIVA) is a common problem in Emergency Departments (EDs), yet the prevalence and clinical impact of this condition is poorly understood. Ultrasound-guided peripheral intravenous catheter (USGPIV) insertion is a successful modality for obtaining intravenous (IV) access in patients with DIVA. OBJECTIVES: We aimed to describe the prevalence of DIVA, explore how DIVA affects delivery of care, and determine if nurse insertion of USGPIV improves care delays among patients with DIVA. METHODS: We retrospectively queried the electronic medical record for all ED patients who had a peripheral IV (PIV) inserted at a tertiary academic medical center from 2015 to 2017. We categorized patients as having DIVA if they required ≥3 PIV attempts or an USGPIV. We compared metrics for care delivery including time-to-IV-access, time-to-laboratory-results, time-to-IV-analgesia, and ED length of stay (LOS) between patients with and without DIVA. We also compared these metrics in patients with DIVA with a physician-inserted USGPIV versus those with a nurse-inserted USGPIV. RESULTS: A total of 147,260 patients were evaluated during the study period. Of these, 13,192 (8.9%) met criteria for DIVA. Patients with DIVA encountered statistically significant delays in time-to-IV-access, time-to-laboratory-results, time-to-IV-analgesia, and ED LOS compared to patients without DIVA (all p < 0.001). Patients with nurse-inserted USGPIVs also had statistically significant improvements in time-to-IV-access, time-to-laboratory-results, time-to-IV-analgesia, and ED LOS compared to patients with physician-inserted USGPIVs (all p < 0.001). CONCLUSION: DIVA affects many ED patients and leads to delays in PIV access-related care. Nurse insertion of USGPIVs improves care in patients with DIVA.

Environmental limits of Rift Valley fever revealed using ecoepidemiological mechanistic models.

Vector-borne diseases (VBDs) of humans and domestic animals are a significant component of the global burden of disease and a key driver of poverty. The transmission cycles of VBDs are often strongly mediated by the ecological requirements of the vectors, resulting in complex transmission dynamics, including intermittent epidemics and an unclear link between environmental conditions and disease persistence. An important broader concern is the extent to which theoretical models are reliable at forecasting VBDs; infection dynamics can be complex, and the resulting systems are highly unstable. Here, we examine these problems in detail using a case study of Rift Valley fever (RVF), a high-burden disease endemic to Africa. We develop an ecoepidemiological, compartmental, mathematical model coupled to the dynamics of ambient temperature and water availability and apply it to a realistic setting using empirical environmental data from Kenya. Importantly, we identify the range of seasonally varying ambient temperatures and water-body availability that leads to either the extinction of mosquito populations and/or RVF (nonpersistent regimens) or the establishment of long-term mosquito populations and consequently, the endemicity of the RVF infection (persistent regimens). Instabilities arise when the range of the environmental variables overlaps with the threshold of persistence. The model captures the intermittent nature of RVF occurrence, which is explained as low-level circulation under the threshold of detection, with intermittent emergence sometimes after long periods. Using the approach developed here opens up the ability to improve predictions of the emergence and behaviors of epidemics of many other important VBDs.

A RETROSPECTIVE REVIEW OF POST-METAMORPHIC MOUNTAIN CHICKEN FROG (LEPTODACTYLUS FALLAX) NECROPSY FINDINGS FROM EUROPEAN ZOOLOGICAL COLLECTIONS, 1998 TO 2018.

The mountain chicken frog (Leptodactylus fallax) is the largest endemic amphibian species in the Western Hemisphere. Since 1998, this critically endangered species has been maintained as a European Endangered Species Programme, but low breeding success and a high mortality rate threaten the sustainability of the captive frog population. In the current study, we analyzed gross and histopathologic postmortem information from 212 mountain chicken frogs that died in European zoological collections from 1998 to 2018. Thin body condition was the most commonly reported finding across all submissions, observed in 125 frogs. The gastrointestinal and urinary systems were reported to have the highest prevalence of pathologic findings on gross and histopathologic examination. Inflammatory disease was the most frequent diagnosis after histopathologic examination of relevant tissues, with intestinal inflammatory disease (n = 76) followed by tubulointerstitial nephritis (n = 26) being the most commonly reported. Neoplasia was reported in 42 of 212 (19.8%) frogs, all of which were adults. A defined cause of death, or reason for euthanasia, was proposed for 164 of 212 (77.4%) frogs, with inflammatory diseases processes (74 of 212; 34.9%) most commonly implicated. Intestinal adenocarcinoma, seemingly restricted to the colon, caused the deaths of 31 adult frogs. Further investigations to determine factors contributing to the high incidence of inflammatory disease processes and neoplasia are advocated to improve the health and sustainability of the captive mountain chicken frog population.

What motivates the masses: Understanding why people contribute to conservation citizen science projects.

Participation in conservation citizen science projects is growing rapidly and approaches to project design are diversifying. There has been a recent shift towards projects characterised by contributors collecting data in isolation and submitting findings online, with little training or opportunities for direct social interaction with other citizen scientists. While research is emerging on developing citizen science projects by optimising technological modalities, little consideration has been given to understanding what motivates individuals to voluntarily contribute data. Here, we use the Volunteer Functions Inventory, combined with open-ended questions, to demonstrate that the two strongest motivations underpinning participation, for both individuals who contribute data systematically (regularly; n = 177) and opportunistically (ad hoc basis; n = 218), are 'Values' and 'Understanding'. People take part in such projects because they have an intrinsic value for the environment and want to support research efforts (representing 'Values'), as well as wanting to learn and gain knowledge (signifying 'Understanding'). Unlike more traditional citizen science projects that involve specific training and considerable time investments, contributors to these newer types of project are not motivated by the potential to develop their career or opportunities for social interaction. The person-level characteristics of contributors considered in this study did not reliably forecast levels of motivation, suggesting that predicting high levels of motivation is inherently more complex than is often speculated. We recommend avenues for future research that may further enhance our understanding of contributor motivations and the characteristics that may underpin levels of motivation.

Mixed Reality Interaction and Presentation Techniques for Medical Visualisations.

Mixed, Augmented and Virtual reality technologies are burgeoning with new applications and use cases appearing rapidly. This chapter provides a brief overview of the fundamental display presentation methods; head-worn, hand-held and projector-based displays. We present a summary of visualisation methods that employ these technologies in the medical domain with a diverse range of examples presented including diagnostic and exploration, intervention and clinical, interaction and gestures, and education.

Detection of Usutu virus infection in wild birds in the United Kingdom, 2020.

In August 2020, as part of a long-term disease surveillance programme, Usutu virus was detected in five Eurasian blackbirds (Turdus merula) and one house sparrow (Passer domesticus) from Greater London, England. This was initially detected by reverse transcription-PCR and was confirmed by virus isolation and by immunohistochemical detection of flavivirus in tissues. Phylogenetic analysis identified Usutu virus African 3.2 lineage, which is prevalent in the Netherlands and Belgium, suggesting a potential incursion from mainland Europe.

Effects of historic and projected climate change on the range and impacts of an emerging wildlife disease.

The global trend of increasing environmental temperatures is often predicted to result in more severe disease epidemics. However, unambiguous evidence that temperature is a driver of epidemics is largely lacking, because it is demanding to demonstrate its role among the complex interactions between hosts, pathogens, and their shared environment. Here, we apply a three-pronged approach to understand the effects of temperature on ranavirus epidemics in UK common frogs, combining in vitro, in vivo, and field studies. Each approach suggests that higher temperatures drive increasing severity of epidemics. In wild populations, ranavirosis incidents were more frequent and more severe at higher temperatures, and their frequency increased through a period of historic warming in the 1990s. Laboratory experiments using cell culture and whole animal models showed that higher temperature increased ranavirus propagation, disease incidence, and mortality rate. These results, combined with climate projections, predict severe ranavirosis outbreaks will occur over wider areas and an extended season, possibly affecting larval recruitment. Since ranaviruses affect a variety of ectothermic hosts (amphibians, reptiles, and fish), wider ecological damage could occur. Our three complementary lines of evidence present a clear case for direct environmental modulation of these epidemics and suggest management options to protect species from disease.

Disentangling serology to elucidate henipa- and filovirus transmission in Madagascar fruit bats.

Bats are reservoirs for emerging human pathogens, including Hendra and Nipah henipaviruses and Ebola and Marburg filoviruses. These viruses demonstrate predictable patterns in seasonality and age structure across multiple systems; previous work suggests that they may circulate in Madagascar's endemic fruit bats, which are widely consumed as human food. We aimed to (a) document the extent of henipa- and filovirus exposure among Malagasy fruit bats, (b) explore seasonality in seroprevalence and serostatus in these bat populations and (c) compare mechanistic hypotheses for possible transmission dynamics underlying these data. To this end, we amassed and analysed a unique dataset documenting longitudinal serological henipa- and filovirus dynamics in three Madagascar fruit bat species. We uncovered serological evidence of exposure to Hendra-/Nipah-related henipaviruses in Eidolon dupreanum, Pteropus rufus and Rousettus madagascariensis, to Cedar-related henipaviruses in E. dupreanum and R. madagascariensis and to Ebola-related filoviruses in P. rufus and R. madagascariensis. We demonstrated significant seasonality in population-level seroprevalence and individual serostatus for multiple viruses across these species, linked to the female reproductive calendar. An age-structured subset of the data highlighted evidence of waning maternal antibodies in neonates, increasing seroprevalence in young and decreasing seroprevalence late in life. Comparison of mechanistic epidemiological models fit to these data offered support for transmission hypotheses permitting waning antibodies but retained immunity in adult-age bats. Our findings suggest that bats may seasonally modulate mechanisms of pathogen control, with consequences for population-level transmission. Additionally, we narrow the field of candidate transmission hypotheses by which bats are presumed to host and transmit potentially zoonotic viruses globally.

Fatal phaeohyphomycosis due to Exophiala sp. infection in a free-living common toad Bufo bufo.

A wild adult female common toad Bufo bufo found dead in Scotland in September 2016 was observed to have hepatomegaly, a large soft tissue mass in the coelomic cavity (2.7 g, 3.5 × 2.3 × 1.8 cm) and numerous dark-red papules (1-2 mm diameter) in the skin and subjacent tissue over the back and dorsal aspects of the limbs. Histopathological examination identified marked hepatitis and coelomitis associated with pigmented fungal hyphae, which are results consistent with a diagnosis of phaeohyphomycosis. Sequencing of the internal transcribed spacer region and the D1-D2 region of the large subunit of the ribosomal RNA gene from affected liver tissue identified the presence of Exophiala (Chaetothyriales) sp., a black yeast previously identified as a cause of amphibian phaeohyphomycosis. To our knowledge, this is the first published report of Exophiala sp. in a wild or captive amphibian in Europe and the first description of phaeohyphomycosis affecting a free-living amphibian in Great Britain. Exophiala spp. are saprobes and opportunistic pathogens. It has been postulated that phaeohyphomycosis is a disease of immunocompromised amphibians; however, we found no evidence of significant concurrent infection or generalised debility in this common toad. Phaeohyphomycosis appears to be a sporadic cause of mortality in amphibians, and this report adds to the growing list of pathogens known to affect wild amphibians in Europe.

Demodicosis in a captive African straw-coloured fruit bat (Eidolon helvum).

Demodicosis is most frequently observed in the domestic dog (Canis familiaris), but it has rarely been reported in bats (Chiroptera). The overpopulation of Demodex spp. that causes dermatological changes is generally associated with a compromised immune system. We describe the gross and histological features of generalized demodicosis in an adult female African straw-coloured fruit bat (Eidolon helvum) drawn from a captive research colony. The histology of the lesions revealed comedones and follicular infundubular cysts harbouring numerous Demodex spp. mites, eliciting a minimal inflammatory response in the adjacent dermis. The histological examination of a full set of tissues did not reveal clear evidence of immunosuppression, although a clinical history of recent abortion and possible stressors due to captivity could be considered risk factors for the demodicosis. Attempts to determine the Demodex species using PCR on DNA extracted from the formalin fixed paraffin embedded tissue failed. This is the first clinical and histological description of demodicosis in Eidolon helvum.

LISTERIA MONOCYTOGENES INFECTION OF FREE-LIVING WESTERN EUROPEAN HEDGEHOGS (ERINACEUS EUROPAEUS).

Listeria monocytogenes is a ubiquitous environmental bacterium that causes disease in a wide range of species. Infection with this pathogen is most frequently diagnosed in ruminant livestock, but is also known to infect people and occasionally wildlife. Postmortem examinations of Western European hedgehogs (Erinaceus europaeus) in Great Britain (2011-2017) identified five (5/266, 2%, 95% confidence interval: 0.8-4.3%) animals with L. monocytogenes infection. The L. monocytogenes isolates comprised three serogroup 1/2a and two serogroup 4 from three multilocus sequence types (2, 37, and 121), all of which were different by single-nucleotide polymorphism analysis, indicating they were distinct and epidemiologically unrelated. These findings are consistent with hedgehogs contracting sporadic infection from the environment, perhaps through eating soil-dwelling invertebrates. Examination of data from scanning surveillance programs focused on other British wildlife species indicates that the hedgehog is one of the wildlife species from which L. monocytogenes has been most frequently identified to date in Great Britain. However, further studies of multiple taxa with comparable sampling efforts are required to assess the relative frequency of L. monocytogenes infection in different wildlife species. The bacterium was isolated from extraintestinal sites in multiple hedgehogs, which may indicate septicemia. However, histological examination was limited and could not discriminate subclinical infection from disease (i.e., listeriosis). Although L. monocytogenes is a zoonotic pathogen, disease in people is typically contracted from the ingestion of contaminated foods. The risk to immunocompetent people of contracting listeriosis from hedgehogs is considered very low to negligible.