scholarly journals The evolution of stage-specific virulence: differential selection of parasites in juveniles

2018 ◽  
Author(s):  
Ryosuke Iritani ◽  
Elisa Visher ◽  
Mike Boots
Keyword(s):  
Infectious Disease ◽  
Stage Structure ◽  
Juvenile Stage ◽  
Oncorhynchus Gorbuscha ◽  
Heterogeneous Environments ◽  
Previous Theory ◽  
Differential Selection ◽  
Host Stage ◽  
The Impact ◽  
Specific Virulence

AbstractThe impact of infectious disease is often very different in juveniles and adults, but theory has focused on the drivers of stage-dependent defense in hosts rather than the potential for stage-dependent virulence evolution. Stage-structure has the potential to be important to the evolution of pathogens because it exposes parasites to heterogeneous environments in terms of both host characteristics and transmission routes. We develop a stage-structured (juvenile-adult) epidemiological model and examine the evolutionary outcomes of stage-specific virulence under the classic assumption of a transmission-virulence trade-off. We show that selection on virulence against adults remains consistent with the classic theory. However, the evolution of juvenile virulence is sensitive to both demography and transmission pathway with higher virulence against juveniles being favored either when the transmission pathway is assortative (juveniles preferentially interact together) and the juvenile stage is short, or in contrast when the transmission pathway is disassortative and the juvenile stage is long. These results highlight the potentially profound effects of host stage-structure on determining parasite virulence in nature. This new perspective may have broad implications for both understanding and managing disease severity.Impact summaryUnderstanding the evolution of parasite virulence remains one of the most important questions in evolutionary ecology. Virulence is often very different in young and old hosts, but previous theory has presumed that these differences are attributed to adaptation in host defense rather than parasite adaptation. However, stage-structure within host populations can expose parasites to heterogeneous environments, which may lead to differential selection on parasite virulence (stage-specific virulence). Surprisingly, no study has investigated the effects of hosts’ stage-structure on the evolution of stage-specific virulence. We present a theoretical analysis to examine when selection can favor higher virulence against juveniles (juvenile-virulence) versus adults (adult-virulence). Our key result is that higher juvenile-virulence is selected for either when the transmission is assortative within age classes and maturation is slow, or when the transmission is disassortative (occurring predominantly between-classes) and maturation is relatively fast. These at first sight contrasting outcomes can be understood as adaptation to the exploitation of the more available host stage. Although the data on assortativity in infectious disease systems is limited, empirical studies for the virulence of Great Island Virus in guillemots (Uria aalge) and for salmon louse in pink salmon (Oncorhynchus gorbuscha) are consistent with our predictions. Our work provides testable predictions for stage-specific virulence and presents a novel mechanism that may explain variation in virulence in nature. There are also management implications for conservation, public health, vaccination programs, and farming to understanding the drivers of stage dependent virulence.

Development of Strategies for Glycopeptide Synthesis: An Overview on the Glycosidic Linkage

2020 ◽  
Vol 24 (21) ◽  
pp. 2475-2497
Author(s):  
Andrea Verónica Rodríguez-Mayor ◽  
German Jesid Peralta-Camacho ◽  
Karen Johanna Cárdenas-Martínez ◽  
Javier Eduardo García-Castañeda
Keyword(s):  
Chemical Synthesis ◽  
Solid Phase ◽  
Building Blocks ◽  
Heterogeneous Environments ◽  
Phase Synthesis ◽  
Low Concentrations ◽  
Biological Sources ◽  
Synthetic Routes ◽  
The Impact ◽  
Potential Use

Glycoproteins and glycopeptides are an interesting focus of research, because of their potential use as therapeutic agents, since they are related to carbohydrate-carbohydrate, carbohydrate-protein, and carbohydrate-lipid interactions, which are commonly involved in biological processes. It has been established that natural glycoconjugates could be an important source of templates for the design and development of molecules with therapeutic applications. However, isolating large quantities of glycoconjugates from biological sources with the required purity is extremely complex, because these molecules are found in heterogeneous environments and in very low concentrations. As an alternative to solving this problem, the chemical synthesis of glycoconjugates has been developed. In this context, several methods for the synthesis of glycopeptides in solution and/or solid-phase have been reported. In most of these methods, glycosylated amino acid derivatives are used as building blocks for both solution and solid-phase synthesis. The synthetic viability of glycoconjugates is a critical parameter for allowing their use as drugs to mitigate the impact of microbial resistance and/or cancer. However, the chemical synthesis of glycoconjugates is a challenge, because these molecules possess multiple reaction sites and have a very specific stereochemistry. Therefore, it is necessary to design and implement synthetic routes, which may involve various protection schemes but can be stereoselective, environmentally friendly, and high-yielding. This review focuses on glycopeptide synthesis by recapitulating the progress made over the last 15 years.

scholarly journals Reducing the Influence of Environmental Factors on Performance of a Diffusion-Based Personal Exposure Kit

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4637
Author(s):  
Huixin Zong ◽  
Peter Brimblecombe ◽  
Li Sun ◽  
Peng Wei ◽  
Kin-Fai Ho ◽  
...  
Keyword(s):  
Exposure Assessment ◽  
Real Time ◽  
Low Cost ◽  
Personal Exposure ◽  
Sensor Technology ◽  
Heterogeneous Environments ◽  
Mathematical Algorithms ◽  
Personal Exposure Assessment ◽  
Address System ◽  
The Impact

Sensor technology has enabled the development of portable low-cost monitoring kits that might supplement many applications in conventional monitoring stations. Despite the sensitivity of electrochemical gas sensors to environmental change, they are increasingly important in monitoring polluted microenvironments. The performance of a compact diffusion-based Personal Exposure Kit (PEK) was assessed for real-time gaseous pollutant measurement (CO, O3, and NO2) under typical environmental conditions encountered in the subtropical city of Hong Kong. A dynamic baseline tracking method and a range of calibration protocols to address system performance were explored under practical scenarios to assess the performance of the PEK in reducing the impact of rapid changes in the ambient environment in personal exposure assessment applications. The results show that the accuracy and stability of the ppb level gas measurement is enhanced even in heterogeneous environments, thus avoiding the need for data post-processing with mathematical algorithms, such as multi-linear regression. This establishes the potential for use in personal exposure monitoring, which has been difficult in the past, and for reporting more accurate and reliable data in real-time to support personal exposure assessment and portable air quality monitoring applications.

scholarly journals On the diverse and opposing effects of nutrition on pathogen virulence

2019 ◽  
Vol 286 (1906) ◽  
pp. 20191220 ◽  
Author(s):  
Victoria L. Pike ◽  
Katrina A. Lythgoe ◽  
Kayla C. King
Keyword(s):  
Infectious Disease ◽  
Immune System ◽  
Meta Analysis ◽  
Anthropogenic Factors ◽  
Anthropogenic Activity ◽  
Pathogen Virulence ◽  
Disease Outcomes ◽  
Host Nutrition ◽  
Opposing Effects ◽  
The Impact

Climate change and anthropogenic activity are currently driving large changes in nutritional availability across ecosystems, with consequences for infectious disease. An increase in host nutrition could lead to more resources for hosts to expend on the immune system or for pathogens to exploit. In this paper, we report a meta-analysis of studies on host–pathogen systems across the tree of life, to examine the impact of host nutritional quality and quantity on pathogen virulence. We did not find broad support across studies for a one-way effect of nutrient availability on pathogen virulence. We thus discuss a hypothesis that there is a balance between the effect of host nutrition on the immune system and on pathogen resources, with the pivot point of the balance differing for vertebrate and invertebrate hosts. Our results suggest that variation in nutrition, caused by natural or anthropogenic factors, can have diverse effects on infectious disease outcomes across species.

scholarly journals Recent insights into microbial triggers of interleukin-10 production in the host and the impact on infectious disease pathogenesis: Table 1

2012 ◽  
Vol 64 (3) ◽  
pp. 295-313 ◽  
Author(s):  
Benjamin L. Duell ◽  
Chee K. Tan ◽  
Alison J. Carey ◽  
Fan Wu ◽  
Allan W. Cripps ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Interleukin 10 ◽  
Disease Pathogenesis ◽  
The Impact

scholarly journals Impact of Infectious Disease Risk Perception on Perceived Retail Crowding: With Special Reference to Retail Industry in Sri Lanka

2020 ◽  
Author(s):  
AISDL
Keyword(s):  
Infectious Disease ◽  
Sri Lanka ◽  
Consumer Behaviour ◽  
Disease Risk ◽  
Positive Influence ◽  
Spatial Density ◽  
Interpersonal Interactions ◽  
Consumption Decision ◽  
The Impact ◽  
Human Density

The global pandemic of COVID 19 has changed consumer behaviour to reduce the risk. This is common for all interpersonal interactions of individuals especially in maintaining the recommended interpersonal distance based on the recommendations from the health experts. Sri Lanka as a developing country affected by COVID 19, observed changes in individuals' day today’ consumption decision making due to pandemic. Importantly the retailing sector is highly influenced by the conditions since the frequency of interpersonal interactions and degree of interaction is higher in the retailing sector. Interestingly the retailing sector with its largest contributor, the SMEs need to identify the unique changes that happen to the consumer behaviour in responding to them. Accordingly, the objective of the study is to examine the impact of infectious disease risk on the perceived retail crowding in two perspectives of human density and the spatial density. The study has used a quantitative survey in collecting data with the online self-administrated questionnaire with a sample of 100 consumers. Data analysis has been done by using a PLS-SEM with the support of SmartPLS version 3. The key findings of the study emphasize the significant positive influence of infectious disease risk on human density as well as on the spatial density. Based on the findings the study attempts to provide the implications for the retailing industry to cope with situational changes in the environment.

Everyday Dangers – The Impact Infectious Disease has on the Health of Paramedics: A Scoping Review

2017 ◽  
Vol 32 (2) ◽  
pp. 217-223 ◽  
Author(s):  
Brodie Thomas ◽  
Peter O’Meara ◽  
Evelien Spelten
Keyword(s):  
Infectious Disease ◽  
Infectious Diseases ◽  
Scoping Review ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Publication Type ◽  
Knowledge And Attitudes ◽  
Immunodeficiency Virus ◽  
Potential Risks ◽  
The Impact ◽  
Mrsa Colonization

AbstractBackgroundParamedics respond to emergency scenes in often uncontrolled settings without being aware of potential risks. This makes paramedicine one of the most dangerous occupations. One of these dangers is the risk of contracting infectious diseases. Research in this area is predominantly focused on compliance in the use of protective equipment, attitudes and perceptions of paramedics, infectious disease policy, and exposure rates to blood and body fluids. The purpose of this scoping review was to determine what is known about the impact of infectious disease on the health of paramedics.MethodsUsing the Arskey and O’Malley methodological framework, a scoping review was undertaken, which allows for a broad search of the available evidence.ResultsThe literature search identified eight articles for review that reported on paramedic exposure trends; the lack of reported blood-borne infections contracted, such as hepatitis B, hepatitis C, and human immunodeficiency virus (HIV); instances of severe acute respiratory syndrome (SARS) infections; and the higher prevalence of methicillin-resistant staphylococcus aureus (MRSA) nasal infections amongst paramedics.ConclusionsExposure to infectious diseases is decreasing, yet it remains significant. The decrease is attributed to prevention strategies; however, paramedic knowledge and attitudes as well as the uncontrolled environment paramedics work in can be a barrier. Contraction of infectious diseases is generally low; exceptions to this are MRSA colonization, influenza, and SARS. Paramedics are at greater risk of acquiring these infectious diseases compared to the general public. The effect on the health of paramedics is not well reported.ThomasB,O’MearaP,SpeltenE.Everyday dangers – the impact infectious disease has on the health of paramedics: a scoping review.Prehosp Disaster Med.2017;32(2):217–223.

scholarly journals The Impact of Organisational Characteristics of Staff and Facility on Infectious Disease Outbreaks in Care Homes: a Systematic Review

2021 ◽  
Author(s):  
Ann Liljas ◽  
Lenke Morath ◽  
Bo Burström ◽  
Pär Schön ◽  
Janne Agerholm
Keyword(s):  
Infectious Disease ◽  
Systematic Review ◽  
Older People ◽  
Disease Outbreaks ◽  
Care Homes ◽  
Facility Design ◽  
Infectious Disease Outbreaks ◽  
Facility Size ◽  
The Impact ◽  
Nurse Aides

Abstract Background: Infectious disease outbreaks are common in care homes, often with substantial impact on the rates of infection and mortality of the residents, who primarily are older people vulnerable to infections. There is growing evidence that organisational characteristics of staff and facility might play a role in infection outbreaks however such evidence have not previously been systematically reviewed. Therefore, this systematic review aims to examine the impact of facility and staff characteristics on the risk of infectious disease outbreaks in care homes.Methods: Five databases were searched. Studies considered for inclusion were of any design reporting on an outbreak of any infectious disease in one or more care homes providing care for primarily older people with original data on: facility size, facility location (urban/rural), facility design, use of temporary hired staff, staff compartmentalizing, residence of staff, and/or nursing aides hours per resident. Retrieved studies were screened, assessed for quality, and analysed employing a narrative synthesis.Results: Sixteen studies (8 cohort studies, 6 cross-sectional studies, 2 case-control) were included from the search which generated 10,424 unique records. COVID-19 was the most commonly reported cause of outbreak (n=11). The other studies focused on influenza, respiratory and gastrointestinal outbreaks. Most studies reported on the impact of facility size (n=11) followed by facility design (n=4), use of temporary hired staff (n=3), facility location (n=2), staff compartmentalizing (n=2), nurse aides hours (n=2) and residence of staff (n=1). Findings suggest that urban location and larger facility size may be associated with greater risks of an infectious outbreak. Additionally, the risk of a larger outbreak seems lower in larger facilities. Whilst staff compartmentalizing may be associated with lower risk of an outbreak, staff residing in highly infected areas may be associated with greater risk of outbreak. The influence of facility design, use of temporary staff, and nurse aides hours remains unclear.Conclusions: This systematic review suggests that larger facilities have greater risks of infectious outbreaks, yet the risk of a larger outbreak seems lower in larger facilities. Due to lack of robust findings the impact of facility and staff characteristics on infectious outbreaks remain largely unknown.PROSPERO: CRD42020213585

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