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Most pathogens threatening to cause extinction of a host species are maintained on one or more reservoir hosts, in addition to the species that is threatened by disease. Further, most conventional host—pathogen theory assumes that transmission is related to host density, and therefore a pathogen should become extinct before its sole host. Tasmanian devil facial tumor disease is a recently emerged infectious cancer that has led to massive population declines and grave concerns for the future persistence of this largest surviving marsupial carnivore. Here we report the results of mark—recapture studies at six sites and use these data to estimate epidemiological parameters critical to both accurately assessing the risk of extinction from this disease and effectively managing this disease threat. Three sites were monitored from before or close to the time of disease arrival, and at three others disease was well established when trapping began, in one site for at least 10 years. We found no evidence for sex-specific differences in disease prevalence and little evidence of consistent seasonal variation in the force of infection. At all sites, the disease was maintained at high levels of prevalence (>50% in 2–3-year-old animals), despite causing major population declines. We also provide the first estimates of the basic reproductive rate R₀ for this disease. Using a simple age-structured deterministic model, we show that our results are not consistent with transmission being proportional to the density of infected hosts but are consistent with frequency-dependent transmission. This conclusion is further supported by the observation that local disease prevalence in 2–3-year-olds still exceeds 50% at a site where population density has been reduced by up to 90% in the past 12 years. These findings lend considerable weight to concerns that this host-specific pathogen will cause the extinction of the Tasmanian devil. Our study highlights the importance of rapidly implementing monitoring programs to determine how transmission depends on host density and emphasizes the need for ongoing management strategies involving a disease-free \"insurance population,\" along with ongoing field monitoring programs to confirm whether local population extinction occurs.

Parks and protected areas have been instrumental in reducing anthropogenic sources of damage in terrestrial and aquatic environments. Pathogen invasion often succeeds physical wounding and injury, yet links between the reduction of damage and the moderation of disease have not been assessed. Here, we examine the utility of no-take marine reserves as tools for mitigating diseases that affect reef-building corals. We found that sites located within reserves had fourfold reductions in coral disease prevalence compared to non-reserve sites (80 466 corals surveyed). Of 31 explanatory variables assessed, coral damage and the abundance of derelict fishing line best explained differences in disease assemblages between reserves and non-reserves. Unexpectedly, we recorded significantly higher levels of disease, coral damage, and derelict fishing line in non-reserves with fishing gear restrictions than in those without gear restrictions. Fishers targeting stocks perceived to be less depleted, coupled with enhanced site access from immediately adjacent boat moorings, may explain these unexpected patterns. Significant correlations between the distance from mooring sites and prevalence values for a ciliate disease known to infest wounded tissue ( r = −0.65), coral damage ( r = −0.64), and the abundance of derelict fishing line ( r = −0.85) corroborate this interpretation. This is the first study to link disease with recreational use intensity in a park, emphasizing the need to evaluate the placement of closures and their direct relationship to ecosystem health. Since corals are modular, ecological processes that govern reproductive and competitive fitness are frequently related to colony surface area therefore, even low levels of cumulative tissue loss from progressing diseases pose significant threats to reef coral persistence. Disease mitigation through reductions in physical injury in areas where human activities are concentrated is another mechanism by which protected areas may improve ecosystem resilience in a changing climate.

Bovine respiratory disease (BRD) is a common endemic disease among North American feedlot cattle. BRD can lead to significant economic losses for individual beef cattle feedlot producers through mortality and morbidity. With promising new management and technology research that could reduce BRD prevalence, this study evaluates the potential impacts of a reduction of BRD in the US beef cattle feedlot sector. Using a multi-market, multi-commodity partial equilibrium economic model of the US agricultural industry, we evaluate the market impacts of reduced BRD to producers from various livestock, meat, and feedstuffs industries. We find that as morbidity and mortality is reduced, beef cattle producers experience losses due to increased supplies (lower beef cattle prices) and increased demand for feedstuff (higher feedstuff prices). Beef cattle processors see gains as the price of beef cattle is lower, whereas feedstuff producers gain from higher feedstuff prices. Producers in the allied industries (pork, lamb, poultry, and eggs) see a small reduction in returns as consumers substitute with less expensive beef products. Consumers see gains in welfare as the increase in beef cattle supply results in lower beef prices. These lower beef prices more than offset the small increases in pork, lamb, poultry, and egg prices. Overall, the potential economic welfare change due to management and technologies that reduce BRD is a net gain for the US society as a whole.

Selected technological solutions can impact health status of animals. The aim of this case study was to determine the effect of different housing systems on disease prevalence and the productive lifespan of dairy cows. In total, 480 cows kept indoors on one farm in four buildings using four different housing systems (a free-stall barn with a slatted floor; a free-stall barn with a self-cleaning floor; an open-pack barn with deep litter; a tie-stall barn with shallow litter) were analyzed. The data from 6 years, based on veterinary reports, were processed statistically in Statistica 13.00. The study demonstrated that the average productive lifespan was longer (p ≤ 0.01), by up to more than 8 months, in the system with deep litter, which was also characterized by the lowest disease prevalence (p ≤ 0.01), especially foot and some reproductive disorders. This trend was maintained in each year of the study period (2015–2020). In the tie-stall barn, the prevalence of mastitis was reduced, but the risk of lameness, retained placenta, parturient paresis and displaced abomasum was higher in this system (p ≤ 0.01). Overall morbidity was highest in the free-stall barns. Lower morbidity was associated with an increase in productive herd life.

Background: This study aimed to investigate the association between evacuation status and lifestyle-related disease risks among Fukushima residents following the Great East Japan earthquake. Methods: Fukushima health management survey respondents were classified into non-evacuees, returnees, evacuees in lifted areas, and evacuees in banned areas. During a seven-year follow-up, 22,234 men and 31,158 women were included. Those with a history of diabetes, hypertension, or dyslipidemia at baseline were excluded. The odds ratios of risk factors (ORs) and 95% confidence intervals (CIs) for diabetes, hypertension, and dyslipidemia were calculated using a logistic regression model. Spatial autocorrelation of the prevalence of these diseases in the Fukushima area in 2017, was calculated to detect the disease prevalence status. Results: The risks of diabetes, hypertension, and dyslipidemia were higher in evacuees in banned areas than in non-evacuees; the multivariable ORs were 1.32 (95% CI: 1.19–1.46), 1.15 (1.06–1.25), and 1.20 (1.11–1.30) for diabetes, hypertension, and dyslipidemia, respectively. Returnees and evacuees in lifted areas had no increased risk of diseases. The area analyzed had a non-uniform spatial distribution of diabetes, hypertension, and hyperlipidemia, with clusters around Fukushima and Koriyama. Conclusion: Our findings imply the need for continuous support for evacuees in banned areas.

Estimating disease-associated mortality and transmission processes is difficult in free-ranging wildlife but important for understanding disease impacts and dynamics and for informing management decisions. In a capture-mark-recapture study, we used a PCR-based diagnostic test in combination with multistate models to provide the first estimates of disease-associated mortality and detection, infection, and recovery rates for frogs endemically infected with the chytrid fungus Batrachochytrium dendrobatidis (Bd), which causes the pandemic amphibian disease chytridiomycosis. We found that endemic chytridiomycosis was associated with a substantial reduction (approximately 38%) in apparent monthly survival of the threatened rainforest treefrog Litoria pearsoniana despite a long period of coexistence (approximately 30 years); detection rate was not influenced by disease status; improved recovery and reduced infection rates correlated with decreased prevalence, which occurred when temperatures increased; and incorporating changes in individuals' infection status through time with multistate models increased effect size and support (98.6% vs. 71% of total support) for the presence of disease-associated mortality when compared with a Cormack-Jolly-Seber model in which infection status was restricted to the time of first capture. Our results indicate that amphibian populations can face significant ongoing pressure from chytridiomycosis long after epidemics associated with initial Bd invasions subside, an important consideration for the long-term conservation of many amphibian species worldwide. Our findings also improve confidence in estimates of disease prevalence in wild amphibians and provide a general framework for estimating parameters in epidemiological models for chytridiomycosis, an important step toward better understanding and management of this disease.

Coral reefs, the most diverse of marine ecosystems, currently experience unprecedented levels of degradation. Diseases are now recognized as a major cause of mortality in reef-forming corals and are complicit in phase shifts of reef ecosystems to algal-dominated states worldwide. Even so, factors contributing to disease occurrence, spread, and impact remain poorly understood. Ecosystem resilience has been linked to the conservation of functional diversity, whereas overfishing reduces functional diversity through cascading, top-down effects. Hence, we tested the hypothesis that reefs with trophically diverse reef fish communities have less coral disease than overfished reefs. We surveyed reefs across the central Philippines, including well-managed marine protected areas (MPAs), and found that disease prevalence was significantly negatively correlated with fish taxonomic diversity. Further, MPAs had significantly higher fish diversity and less disease than unprotected areas. We subsequently investigated potential links between coral disease and the trophic components of fish diversity, finding that only the density of coral-feeding chaetodontid butterflyfishes, seldom targeted by fishers, was positively associated with disease prevalence. These previously uncharacterized results are supported by a second large-scale dataset from the Great Barrier Reef. We hypothesize that members of the charismatic reef-fish family Chaetodontidae are major vectors of coral disease by virtue of their trophic specialization on hard corals and their ecological release in overfished areas, particularly outside MPAs.

Aims The effect of microbial preparations on plant growth and resistance to diseases depends on plant genotype and growth conditions limiting their use in agriculture. Various biocontrol effects, reported for the endophyte Methylobacterium sp. IMBG290, are possibly modulated through the endophyte community of the potato (Solarium tuberosum L.) host. In the current study, we analyzed growth promoting and biocontrol capacities of IMBG290 alone and when combined with commercial bacterial preparation under field conditions. Methods The effect of microbial inoculants on potato growth and disease prevalence was monitored during 2-year field experiment and matched with metagenomic analysis results of potato endophytic community. Results The effect of microbial inoculants on plant growth and disease prevalence varied from positive to negative depending on potato cultivar, bacterial treatment and environmental conditions. A culti vardependent synergistic effect of combined inoculation was observed. The positive effect of bacterial treatments was associated with a shift in the structure of communities of bacterial and fungal endophytes. Conclusions Cultivar-environment interaction associated with a shift in the endophytic microbial community play a role in the potato response to bacterial preparations. This should be considered when designing complex microbial inoculants.

Disease epidemics typically begin as an outbreak of a relatively small, spatially explicit population of infected individuals (focus), in which disease prevalence increases and rapidly spreads into the uninfected, at‐risk population. Studies of epidemic spread typically address factors influencing disease spread through the at‐risk population, but the initial outbreak may strongly influence spread of the subsequent epidemic. We initiated wheat stripe rust Puccinia striiformis f. sp. tritici epidemics to assess the influence of the focus on final disease prevalence when the degree of disease susceptibility differed between the at‐risk and focus populations. When the focus/at‐risk plantings consisted of partially genetic resistant and susceptible cultivars, final disease prevalence was statistically indistinguishable from epidemics produced by the focus cultivar in monoculture. In these experimental epidemics, disease prevalence was not influenced by the transition into an at‐risk population that differed in disease susceptibility. Instead, the focus appeared to exert a dominant influence on the subsequent epidemic. Final disease prevalence was not consistently attributable to either the focus or the at‐risk population when focus/at‐risk populations were planted in a factorial set‐up with a mixture (c. 28% susceptible and 72% resistant) and susceptible individuals. In these experimental epidemics, spatial heterogeneity in disease susceptibility within the at‐risk population appeared to counter the dominant influence of the focus. Cessation of spore production from the focus (through fungicide/glyphosate application) after 1·3 generations of stripe rust spread did not reduce final disease prevalence, indicating that the focus influence on disease spread is established early in the epidemic. Synthesis and applications. Our experiments indicated that outbreak conditions can be highly influential on epidemic spread, even when disease resistance in the at‐risk population is greater than that of the focus. Disease control treatments administered shortly after the initial outbreak within the focus may either prevent an epidemic from occurring or reduce its severity.

Aims: The aim of this study is to find the association of chronic disease prevalence (CDP) with suicide-related ideation (SI) and suicide attempt (SA) and to determine the combined effect of CDP and quality of life (QoL) with SI or SA. Design: This was a cross-sectional study. Materials and Methods: The data were collected from the nationally representative Korea National Health and Nutrition Examination Survey IV and V (2007-2012). For the analysis, a total of 35,075 adult participants were selected as the final sample, which included 5773 participants with SI and 331 with SA. Statistical Analysis: Multiple logistic regression models were used to examine the odds ratio after adjusting for age, sex, marital status, education, occupation, and household income. Results and Conclusion: SI was positively associated with selected CDP, such as cardiovascular disease (CVD), stroke, ischemic heart disease (IHD), cancer, diabetes, renal failure, and depression, except hypertension. Subjects with CVD, IHD, renal failure, and depression were found likely to have increased odds for SA as compared to non-SA controls. Lower QoL strongly affected SI and SA. Furthermore, the likelihood of SI increased for depressed and cancer subjects who had low QoL in comparison to subjects with high QoL and without chronic disease. Similarly, statistically, significant interaction was observed between lower QoL and depression in relation to SA compared to non-SA controls. These data suggest that suicide-related behavior could be predicted by the prevalence of chronic disease and low QoL.