scholarly journals Mixed Effects of Habitat Degradation and Resources on Hantaviruses in Sympatric Wild Rodent Reservoirs within a Neotropical Forest

Viruses ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 85
Author(s):  
Jeremy V. Camp ◽  
Briana Spruill-Harrell ◽  
Robert D. Owen ◽  
Carles Solà-Riera ◽  
Evan P. Williams ◽  
...  
Keyword(s):  
Habitat Degradation ◽  
Dilution Effect ◽  
Host Population ◽  
Resource Augmentation ◽  
Neotropical Forest ◽  
Habitat Composition ◽  
Primary Driver ◽  
Rodent Community ◽  
Reservoir Hosts ◽  
Over Time

Understanding the ecology of rodent-borne hantaviruses is critical to assessing the risk of spillover to humans. Longitudinal surveys have suggested that hantaviral prevalence in a given host population is tightly linked to rodent ecology and correlates with changes in the species composition of a rodent community over time and/or habitat composition. We tested two hypotheses to identify whether resource addition and/or habitat composition may affect hantavirus prevalence among two sympatric reservoir hosts in a neotropical forest: (i) increased food resources will alter the rodent community and thus hantaviral prevalence; and (ii) host abundance and viral seroprevalence will be associated with habitat composition. We established a baseline of rodent–virus prevalence in three grid pairs of distinct habitat compositions and subjected one grid of each pair to resource augmentation. Increased rodent species diversity was observed on grids where food was added versus untreated control grids during the first post-treatment sampling session. Resource augmentation changed species community composition, yet it did not affect the prevalence of hantavirus in the host population over time, nor was there evidence of a dilution effect. Secondly, we show that the prevalence of the virus in the respective reservoir hosts was associated with habitat composition at two spatial levels, independent of resource addition, supporting previous findings that habitat composition is a primary driver of the prevalence of hantaviruses in the neotropics.

scholarly journals Human infectious disease burdens decrease with urbanization but not with biodiversity

2017 ◽  
Vol 372 (1722) ◽  
pp. 20160122 ◽  
Author(s):  
Chelsea L. Wood ◽  
Alex McInturff ◽  
Hillary S. Young ◽  
DoHyung Kim ◽  
Kevin D. Lafferty
Keyword(s):  
Infectious Disease ◽  
Infectious Diseases ◽  
Disease Transmission ◽  
Scientific Evidence ◽  
Dilution Effect ◽  
Policy Implications ◽  
Global Public Health ◽  
Country Level ◽  
Life Years ◽  
Over Time

Infectious disease burdens vary from country to country and year to year due to ecological and economic drivers. Recently, Murray et al. (Murray CJ et al . 2012 Lancet 380 , 2197–2223. ( doi:10.1016/S0140-6736(12)61689-4 )) estimated country-level morbidity and mortality associated with a variety of factors, including infectious diseases, for the years 1990 and 2010. Unlike other databases that report disease prevalence or count outbreaks per country, Murray et al. report health impacts in per-person disability-adjusted life years (DALYs), allowing comparison across diseases with lethal and sublethal health effects. We investigated the spatial and temporal relationships between DALYs lost to infectious disease and potential demographic, economic, environmental and biotic drivers, for the 60 intermediate-sized countries where data were available and comparable. Most drivers had unique associations with each disease. For example, temperature was positively associated with some diseases and negatively associated with others, perhaps due to differences in disease agent thermal optima, transmission modes and host species identities. Biodiverse countries tended to have high disease burdens, consistent with the expectation that high diversity of potential hosts should support high disease transmission. Contrary to the dilution effect hypothesis, increases in biodiversity over time were not correlated with improvements in human health, and increases in forestation over time were actually associated with increased disease burden. Urbanization and wealth were associated with lower burdens for many diseases, a pattern that could arise from increased access to sanitation and healthcare in cities and increased investment in healthcare. The importance of urbanization and wealth helps to explain why most infectious diseases have become less burdensome over the past three decades, and points to possible levers for further progress in improving global public health. This article is part of the themed issue ‘Conservation, biodiversity and infectious disease: scientific evidence and policy implications’.

The influence of landscape and environmental factors on ranavirus epidemiology in amphibian assemblages

2017 ◽  
Author(s):  
Brian J. Tornabene ◽  
Andrew R. Blaustein ◽  
Cheryl J. Briggs ◽  
Dana M. Calhoun ◽  
Pieter T. J. Johnson ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Host Species ◽  
Dilution Effect ◽  
Variance Partitioning ◽  
Lower Probability ◽  
Infection Prevalence ◽  
Taxonomic Richness ◽  
Amphibian Disease ◽  
Competing Models ◽  
Reservoir Hosts

ABSTRACTAimTo quantify the influence of a suite of landscape, abiotic, biotic, and host-level variables on ranavirus disease dynamics in amphibian assemblages at two biological levels (site and host-level).LocationWetlands within the East Bay region of California, USA.MethodsWe used competing models, multimodel inference, and variance partitioning to examine the influence of 16 landscape and environmental factors on patterns in site-level ranavirus presence and host-level ranavirus infection in 76 wetlands and 1,377 amphibian hosts representing five species.ResultsThe landscape factor explained more variation than any other factors in site-level ranavirus presence, but biotic and host-level factors explained more variation in host-level ranavirus infection. At both the site- and host-level, the probability of ranavirus presence correlated negatively with distance to nearest ranavirus-positive wetland. At the site-level, ranavirus presence was associated positively with taxonomic richness. However, infection prevalence within the amphibian population correlated negatively with vertebrate richness. Finally, amphibian host species differed in their likelihood of ranavirus infection: American Bullfrogs had the weakest association with infection while Western Toads had the strongest. After accounting for host species effects, hosts with greater snout-vent length had a lower probability of infection.Main conclusionsStrong spatial influences at both biological levels suggest that mobile taxa (e.g., adult amphibians, birds, reptiles) may facilitate the movement of ranavirus among hosts and across the landscape. Higher taxonomic richness at sites may provide more opportunities for colonization or the presence of reservoir hosts that may influence ranavirus presence. Higher host richness correlating with higher ranavirus infection is suggestive of a dilution effect that has been observed for other amphibian disease systems and warrants further investigation. Our study demonstrates that an array of landscape, environmental, and host-level factors were associated with ranavirus epidemiology and illustrates that their importance vary with biological level.

Improving anti-emetics in chemotherapy induced nausea and vomiting.

2016 ◽  
Vol 34 (7_suppl) ◽  
pp. 220-220 ◽  
Author(s):  
Sandra Toutounji ◽  
Ron Fung ◽  
Katherine Enright
Keyword(s):  
Quality Improvement ◽  
Target Duration ◽  
Nausea And Vomiting ◽  
Primary Driver ◽  
American Society ◽  
New Guidelines ◽  
Dose Modifications ◽  
Primary Measure ◽  
Over Time

220 Background: Chemotherapy induced nausea and vomiting (CINV) remains one of the most feared treatment-related toxicities in cancer patients. CINV has been shown to decrease quality of life and to increase dose modifications and unplanned hospital visits. Cancer Care Ontario (CCO) and the American Society of Clinical Oncology (ASCO) updated their CINV guidelines in 2013. These changes included a reclassification of many regimens from moderate (MEC) to highly emetogenic (HEC) and a decrease in the duration of serotonin inhibitors (5HT3i). Uptake of the new guidelines at Trillium Health Partners has been slow. We aimed to improve CINV by increasing the percentage of patients who received guideline concordant anti-emetics with their first cycle of HEC/MEC chemotherapy. Methods: The first 25 patients started on MEC/HEC chemotherapy during 3 time periods (pre-guidelines, 6 months post guidelines, 1.5 years post guidelines) were identified. The primary measure of interest was the percentage of patients receiving MEC/HEC who were treated in concordance with the updated CINV guidelines. Secondary measures included the percentage of MEC/HEC patients who experienced grade 2+ CINV. The collected data was used with quality improvement techniques to guide the development of interventions to improve guideline concordance. Results: The concordance of anti-emetics on the day of chemotherapy improved over time, but post-chemotherapy concordance remained at 0% (table). The primary driver for concordance was the use of NK1inhibitors on chemotherapy day, and the duration of 5HT3i post-chemotherapy. Using quality improvement methodology, the highest impact intervention was identified as changing the default settings in the computerized order entry system (CPOE) to reflect the updated guidelines. These changes are currently in progress and a test of this change will be presented. Conclusions: Concordance with CINV guidelines improved over time resulting in lower CINV and less need for reactive CINV interventions. Further work to target duration of 5HT3i is ongoing. [Table: see text]

scholarly journals How to find natural reservoir hosts from endemic prevalence in a multi-host population: A case study of influenza in waterfowl

Epidemics ◽  
2009 ◽  
Vol 1 (2) ◽  
pp. 118-128 ◽  
Author(s):  
Hiroshi Nishiura ◽  
Bethany Hoye ◽  
Marcel Klaassen ◽  
Silke Bauer ◽  
Hans Heesterbeek
Keyword(s):  
Host Population ◽  
Natural Reservoir ◽  
Reservoir Hosts

scholarly journals Explaining the moderate platform of the Syrian Muslim Brotherhood: Against the inclusion-moderation hypothesis

2021 ◽  
Author(s):  
◽  
Hanlie Booysen
Keyword(s):  
Muslim Brotherhood ◽  
Target Audience ◽  
Political Arena ◽  
Primary Target ◽  
Political Processes ◽  
Primary Driver ◽  
Political Objective ◽  
Moderate Policy ◽  
Parliamentary Politics ◽  
Over Time

<p>Throughout its existence, the Syrian Muslim Brotherhood (SMB) has consistently maintained a moderate policy on governance. The main aim of this study is to explain this moderation. Previous literature has usually explained moderation in similar movements by an “inclusion-moderation hypothesis”, which holds that moderation results when movements have the opportunity to participate in pluralist political processes. However, the SMB has been progressively excluded from the Syrian political arena since 1963. The inclusion-moderation hypothesis implies, as its converse, that exclusion leads to radicalisation. This study shows that contrary to this expectation, the SMB’s ultimate exclusion from the Syrian political arena in 1982 was in fact the primary driver of its moderate policy. The SMB also participated in parliamentary politics in its early history, and therefore has not moderated over time, as the inclusion-moderation hypothesis would require. Thus, the inclusion-moderation hypothesis does not work for this case, and this dissertation advances an alternate explanation for the SMB’s continued commitment to a moderate policy on governance.  This study’s central thesis is that the SMB’s moderate policy on governance can be explained by the Brotherhood’s primary target audience, that is to say, the political force which, in the SMB’s view, can deliver its political objective. As this definition implies, the target audience shifts over time, in accordance with changing circumstances. In 1980, the primary target audience comprised diverse actors in opposition to the al-Asad government: the Fighting Vanguard, the Syrian ulama, and the secularist opposition. In 2001, the audience was the Bashar al-Asad government. In 2004, it was the secularist opposition; and in 2012, it was the foreign sponsors of the secularist opposition.</p>

scholarly journals Temporal Dynamics of Wheat Blast Epidemics and Disease Measurements Using Multispectral Imagery

2020 ◽  
Vol 110 (2) ◽  
pp. 393-405 ◽  
Author(s):  
C. Gongora-Canul ◽  
J. D. Salgado ◽  
D. Singh ◽  
A. P. Cruz ◽  
L. Cotrozzi ◽  
...  
Keyword(s):  
Field Experiments ◽  
Temporal Dynamics ◽  
Logistic Models ◽  
Correlation Coefficients ◽  
Host Population ◽  
Multispectral Imagery ◽  
Susceptible Host ◽  
Wheat Blast ◽  
Accuracy And Precision ◽  
Over Time

Wheat blast is a devastating disease caused by the Triticum pathotype of Magnaporthe oryzae. M. oryzae Triticum is capable of infecting leaves and spikes of wheat. Although symptoms of wheat spike blast (WSB) are quite distinct in the field, symptoms on leaves (WLB) are rarely reported because they are usually inconspicuos. Two field experiments were conducted in Bolivia to characterize the change in WLB and WSB intensity over time and determine whether multispectral imagery can be used to accurately assess WSB. Disease progress curves (DPCs) were plotted from WLB and WSB data, and regression models were fitted to describe the nature of WSB epidemics. WLB incidence and severity changed over time; however, the mean WLB severity was inconspicuous before wheat began spike emergence. Overall, both Gompertz and logistic models helped to describe WSB intensity DPCs fitting classic sigmoidal shape curves. Lin’s concordance correlation coefficients were estimated to measure agreement between visual estimates and digital measurements of WSB intensity and to estimate accuracy and precision. Our findings suggest that the change of wheat blast intensity in a susceptible host population over time does not follow a pattern of a monocyclic epidemic. We have also demonstrated that WSB severity can be quantified using a digital approach based on nongreen pixels. Quantification was precise (0.96 < r> 0.83) and accurate (0.92 < ρ > 0.69) at moderately low to high visual WSB severity levels. Additional sensor-based methods must be explored to determine their potential for detection of WLB and WSB at earlier stages.

scholarly journals Suicide risk among refugees compared with non-refugee migrants and the Swedish-born majority population

2019 ◽  
Vol 217 (6) ◽  
pp. 686-692 ◽  
Author(s):  
Anna-Clara Hollander ◽  
Alexandra Pitman ◽  
Hugo Sjöqvist ◽  
Glyn Lewis ◽  
Cecilia Magnusson ◽  
...  
Keyword(s):  
Suicide Risk ◽  
Cox Regression ◽  
Population Based ◽  
Host Population ◽  
Hazard Ratio ◽  
Additional Risk Factor ◽  
Migrant Status ◽  
Increased Risk ◽  
Majority Population ◽  
Over Time

BackgroundIt has been hypothesised that refugees have an increased risk of suicide.AimsTo investigate whether risk of suicide is higher among refugees compared with non-refugee migrants from the same areas of origin and with the Swedish-born population, and to examine whether suicide rates among migrants converge to the Swedish-born population over time.MethodA population-based cohort design using linked national registers to follow 1 457 898 people born between 1 January 1970 and 31 December 1984, classified by migrant status as refugees, non-refugee migrants or Swedish-born. Participants were followed from their 16th birthday or date of arrival in Sweden until death, emigration or 31 December 2015, whichever came first. Cox regression models estimated adjusted hazard ratios for suicide by migrant status, controlling for age, gender, region of origin and income.ResultsThere were no significant differences in suicide risk between refugee and non-refugee migrants (hazard ratio 1.28, 95% CI 0.93–1.76) and both groups had a lower risk of suicide than Swedish born. During their first 5 years in Sweden no migrants died by suicide; however, after 21–31 years their suicide risk was equivalent to the Swedish-born population (hazard ratio 0.94, 95% CI 0.79–1.22). After adjustment for income this risk was significantly lower for migrants than the Swedish-born population.ConclusionsBeing a refugee was not an additional risk factor for suicide. Our findings regarding temporal changes in suicide risk suggest that acculturation and socioeconomic deprivation may account for a convergence of suicide risk between migrants and the host population over time.Declaration of interestNone.

Traditional ecological knowledge, shifting baselines, and conservation of Fijian molluscs

2017 ◽  
Vol 23 (1) ◽  
pp. 81 ◽  
Author(s):  
Karen Bao ◽  
Joshua Drew
Keyword(s):  
Traditional Ecological Knowledge ◽  
Historical Data ◽  
Habitat Degradation ◽  
Human Perception ◽  
Ecological Knowledge ◽  
Ecological History ◽  
Trends Over Time ◽  
Preservation And Restoration ◽  
Conservation Plans ◽  
Over Time

Understanding a region’s ecological history is crucial in formulating conservation plans. In the absence of conventional datasets, historical data and traditional ecological knowledge of local communities can elucidate trends over time and help set goals for preservation and restoration. These methods can contribute to the conservation of biologically and culturally significant species, including coral reef molluscs, in the South Pacific, which have experienced intensified threats such as overfishing and habitat degradation in recent decades. Through fisher interviews in a small coastal community in Fiji, we investigate changes in distribution, biomass, and human perception of common mollusc populations in a Fijian reef. We found evidence of a decline in mollusc populations, but only older fishers with more fishing experience perceived this decline, suggesting a shift in baseline perceptions of biodiversity.

scholarly journals Two Properties of a Gene-for-Gene Coevolution System under Human Perturbations

1999 ◽  
Vol 89 (9) ◽  
pp. 811-816 ◽  
Author(s):  
P. Sun ◽  
X. B. Yang
Keyword(s):  
Real World ◽  
Host Population ◽  
Resistant Genotype ◽  
Human Perturbation ◽  
Boom And Bust ◽  
Human Perturbations ◽  
Pathogen Populations ◽  
Host Parasite ◽  
Over Time ◽  
Gene For Gene

Recently, the gene-for-gene host-parasite coevolution model of Leonard was extended by incorporating two kinds of perturbations. The first kind was the natural perturbations that include those caused by pathogen migration between the two subpopulations of the host, forward and backward mutations in the host or pathogen populations, and some others. The second kind was human perturbations, such as constantly increasing the percentage of the resistant genotype within the host population each season. In this study, we quantitatively compared the two kinds of perturbations and extended the constantly changing human perturbation to include non-constant perturbations that are more likely to occur in the real world. Two properties of the modified Leonard model were revealed from this study. First, when both human perturbations and natural perturbations are involved, the effects of natural perturbations are very small compared with those of human perturbations. This finding ensures that, in the study of human perturbations, we can simplify the study by ignoring the effects of natural perturbations. Second, through the simulation of nonconstant perturbations, which assumes that the proportion of the resistant genotype of the host population increases over time, we found that the model reproduces the “boom and bust” epidemic cycles that are often found in agroecosystems.

scholarly journals Rats in the city: implications for zoonotic disease risk in an urbanizing world

2021 ◽  
Author(s):  
Kim Rebecca Blasdell ◽  
Serge Morand ◽  
Susan G W Laurance ◽  
Stephen L Doggett ◽  
Amy Hahs ◽  
...  
Keyword(s):  
Disease Risk ◽  
Rattus Rattus ◽  
Zoonotic Disease ◽  
Microbial Pathogens ◽  
Abundance And Diversity ◽  
Impact Of Urbanization ◽  
Rodent Community ◽  
And Function ◽  
The Impact ◽  
Reservoir Hosts

Urbanization is rapidly transforming much of Southeast Asia, altering the structure and function of the landscape, as well as the frequency and intensity of the interactions between people, animals, and the environment. In this study, we began to explore the impact of urbanization on zoonotic disease risk by simultaneously characterizing changes in the abundance and diversity of reservoir hosts (rodents), ectoparasite vectors (ticks), and microbial pathogens across a gradient of urbanization in Malaysian Borneo. We found that although rodent species diversity decreased with increasing urbanization, two species appeared to thrive in anthropogenic environments: the invasive urban exploiter, Rattus rattus and the native urban adapter, Sundamys muelleri. R. rattus was strongly associated with the presence of built infrastructure across the gradient and dominated the urban rodent community where it was associated with high microbial diversity and multi-host zoonoses capable of environmental transmission, including Leptospira spp., and Toxoplasma gondii. In contrast, S. muelleri was restricted to sites with a significant vegetative component where it was found at high densities in the urban location. This species was strongly associated with the presence of ticks, including the medically important genera Ambylomma, Haemaphysalis, and Ixodes. Overall, our results demonstrate that the response to urbanization varies by species at all levels: host, ectoparasite, and microbe. This may lead to increased zoonotic disease risk in a subset of environments across urban and urbanizing landscapes that can be reduced through improved pest management and public health messaging.

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