scholarly journals Lymphatic filariasis: a snap shot of a neglected tropical disease

2021 ◽  
Vol 8 (7) ◽  
pp. 3611
Author(s):  
Alfred Allan Duker ◽  
Efiba Vidda Senkyire Kwarteng
Keyword(s):  
Immune Responses ◽  
Lymphatic Filariasis ◽  
Social Economic ◽  
Climatic Factors ◽  
Control Strategies ◽  
Global Scale ◽  
Eastern Africa ◽  
Western India ◽  
Nematode Larvae ◽  
Micro Level

Lymphatic filariasis (LF) is a leading cause of disability worldwide and one of the most crippling and stigmatizing tropical diseases. LF transmission is widespread throughout regions of West Africa, coastal and south-eastern Africa, East and South-east Asia, South western India, Western Pacific and parts of South and Central America. The disease manifests as disfiguring pathology caused by microfilariae larvae damage to lymph vessels and nodes. LF is spread by mosquitoes that have been infected with filarial nematode larvae and about a billion people in 52 countries are thought to be at risk of contracting the disease on a global scale. Complex immune responses to filaria and their endosymbionts cause the pathologies associated with lymphatic filariasis. Several studies show that non-climatic factors that may be responsible for LF transmission at the micro level include environmental, social, economic, and demographic factors. Currently, the infection is controlled by mass drug administration regimens, vector control strategies and management of morbidities. This review discusses the ecological drivers of lymphatic filariasis transmissions in endemic hotspots.  

scholarly journals Global Analysis of Atmospheric Transmissivity Using Cloud Cover, Aridity and Flux Network Datasets

2021 ◽  
Vol 13 (9) ◽  
pp. 1716
Author(s):  
Ankur Srivastava ◽  
Jose F. Rodriguez ◽  
Patricia M. Saco ◽  
Nikul Kumari ◽  
Omer Yetemen
Keyword(s):  
Cloud Cover ◽  
Climatic Factors ◽  
Global Analysis ◽  
Empirical Relationship ◽  
Aridity Index ◽  
Global Scale ◽  
Empirical Models ◽  
Coefficient Of Determination ◽  
Crop Modeling ◽  
Atmospheric Transmissivity

Atmospheric transmissivity (τ) is a critical factor in climatology, which affects surface energy balance, measured at a limited number of meteorological stations worldwide. With the limited availability of meteorological datasets in remote areas across different climatic regions, estimation of τ is becoming a challenging task for adequate hydrological, climatic, and crop modeling studies. The availability of solar radiation data is comparatively less accessible on a global scale than the temperature and precipitation datasets, which makes it necessary to develop methods to estimate τ. Most of the previous studies provided region specific datasets of τ, which usually provide local assessments. Hence, there is a necessity to give the empirical models for τ estimation on a global scale that can be easily assessed. This study presents the analysis of the τ relationship with varying geographic features and climatic factors like latitude, aridity index, cloud cover, precipitation, temperature, diurnal temperature range, and elevation. In addition to these factors, the applicability of these relationships was evaluated for different climate types. Thus, empirical models have been proposed for each climate type to estimate τ by using the most effective factors such as cloud cover and aridity index. The cloud cover is an important yet often overlooked factor that can be used to determine the global atmospheric transmissivity. The empirical relationship and statistical indicator provided the best performance in equatorial climates as the coefficient of determination (r2) was 0.88 relatively higher than the warm temperate (r2 = 0.74) and arid regions (r2 = 0.46). According to the results, it is believed that the analysis presented in this work is applicable for estimating the τ in different ecosystems across the globe.

scholarly journals Structural equation modeling to shed light on the controversial role of climate on the spread of SARS-CoV-2

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Alessia Spada ◽  
Francesco Antonio Tucci ◽  
Aldo Ummarino ◽  
Paolo Pio Ciavarella ◽  
Nicholas Calà ◽  
...  
Keyword(s):  
Structural Equation Modeling ◽  
Population Density ◽  
Structural Equation ◽  
Climatic Factors ◽  
Demographic Data ◽  
Factor Loading ◽  
Statistical Technique ◽  
Global Scale ◽  
Equation Modeling ◽  
Relevant Role

AbstractClimate seems to influence the spread of SARS-CoV-2, but the findings of the studies performed so far are conflicting. To overcome these issues, we performed a global scale study considering 134,871 virologic-climatic-demographic data (209 countries, first 16 weeks of the pandemic). To analyze the relation among COVID-19, population density, and climate, a theoretical path diagram was hypothesized and tested using structural equation modeling (SEM), a powerful statistical technique for the evaluation of causal assumptions. The results of the analysis showed that both climate and population density significantly influence the spread of COVID-19 (p < 0.001 and p < 0.01, respectively). Overall, climate outweighs population density (path coefficients: climate vs. incidence = 0.18, climate vs. prevalence = 0.11, population density vs. incidence = 0.04, population density vs. prevalence = 0.05). Among the climatic factors, irradiation plays the most relevant role, with a factor-loading of − 0.77, followed by temperature (− 0.56), humidity (0.52), precipitation (0.44), and pressure (0.073); for all p < 0.001. In conclusion, this study demonstrates that climatic factors significantly influence the spread of SARS-CoV-2. However, demographic factors, together with other determinants, can affect the transmission, and their influence may overcome the protective effect of climate, where favourable.

scholarly journals Global Habitat Suitability of Spodoptera frugiperda (JE Smith) (Lepidoptera, Noctuidae): Key Parasitoids Considered for Its Biological Control

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 273
Author(s):  
Ghislain T. Tepa-Yotto ◽  
Henri E. Z. Tonnang ◽  
Georg Goergen ◽  
Sevgan Subramanian ◽  
Emily Kimathi ◽  
...  
Keyword(s):  
Biological Control ◽  
Spodoptera Frugiperda ◽  
Habitat Suitability ◽  
Learning Algorithm ◽  
Global Scale ◽  
Congo Basin ◽  
Eastern Africa ◽  
Cotesia Marginiventris ◽  
Coastal Belt ◽  
Eastern Australia

The present study is the first modeling effort at a global scale to predict habitat suitability of fall armyworm (FAW), Spodoptera frugiperda and its key parasitoids, namely Chelonus insularis, Cotesia marginiventris,Eiphosoma laphygmae,Telenomus remus and Trichogramma pretiosum, to be considered for biological control. An adjusted procedure of a machine-learning algorithm, the maximum entropy (Maxent), was applied for the modeling experiments. Model predictions showed particularly high establishment potential of the five hymenopteran parasitoids in areas that are heavily affected by FAW (like the coastal belt of West Africa from Côte d’Ivoire (Ivory Coast) to Nigeria, the Congo basin to Eastern Africa, Eastern, Southern and Southeastern Asia and some portions of Eastern Australia) and those of potential invasion risks (western & southern Europe). These habitats can be priority sites for scaling FAW biocontrol efforts. In the context of global warming and the event of accidental FAW introduction, warmer parts of Europe are at high risk. The effect of winter on the survival and life cycle of the pest in Europe and other temperate regions of the world are discussed in this paper. Overall, the models provide pioneering information to guide decision making for biological-based medium and long-term management of FAW across the globe.

Immune responses of B. malayi thioredoxin (TRX) and venom allergen homologue (VAH) chimeric multiple antigen for lymphatic filariasis

2013 ◽  
Vol 58 (4) ◽  
Author(s):  
Gandhirajan Anugraha ◽  
Parasurama Jeyaprita ◽  
Jayaprakasam Madhumathi ◽  
Tamilvanan Sheeba ◽  
Perumal Kaliraj
Keyword(s):  
Immune Responses ◽  
Fusion Protein ◽  
Lymphatic Filariasis ◽  
Protein Vaccine ◽  
Mice Model ◽  
Vaccine Strategy ◽  
Single Antigen ◽  
High Level ◽  
Venom Allergen Homologue ◽  
Venom Allergen

AbstractAlthough multiple vaccine strategy for lymphatic filariasis has provided tremendous hope, the choice of antigens used in combination has determined its success in the previous studies. Multiple antigens comprising key vaccine candidates from different life cycle stages would provide a promising strategy if the antigenic combination is chosen by careful screening. In order to analyze one such combination, we have used a chimeric construct carrying the well studied B. malayi antigens thioredoxin (BmTRX) and venom allergen homologue (BmVAH) as a fusion protein (TV) and evaluated its immune responses in mice model. The efficacy of fusion protein vaccine was explored in comparison with the single antigen vaccines and their cocktail. In mice, TV induced significantly high antibody titer of 1,28,000 compared to cocktail vaccine TRX+VAH (50,000) and single antigen vaccine TRX (16,000) or VAH (50,000). Furthermore, TV elicited higher level of cellular proliferative response together with elevated levels of IFN-γ, IL-4 and IL-5 indicating a Th1/Th2 balanced response. The isotype antibody profile showed significantly high level of IgG1 and IgG2b confirming the balanced response elicited by TV. Immunization with TV antigen induced high levels of both humoral and cellular immune responses compared to either cocktail or antigen given alone. The result suggests that TV is highly immunogenic in mice and hence the combination needs to be evaluated for its prophylactic potential.

scholarly journals To React or Not to React: The Dilemma of Fish Immune Systems Facing Myxozoan Infections

2021 ◽  
Vol 12 ◽  
Author(s):  
Astrid S. Holzer ◽  
M. Carla Piazzon ◽  
Damien Barrett ◽  
Jerri L. Bartholomew ◽  
Ariadna Sitjà-Bobadilla
Keyword(s):  
Immune Responses ◽  
Immune Evasion ◽  
B Lymphocyte ◽  
Control Strategies ◽  
Abiotic Factors ◽  
Passive Immunization ◽  
Life Cycles ◽  
Economic Losses ◽  
Special Focus ◽  
Host Immune System

Myxozoans are microscopic, metazoan, obligate parasites, belonging to the phylum Cnidaria. In contrast to the free-living lifestyle of most members of this taxon, myxozoans have complex life cycles alternating between vertebrate and invertebrate hosts. Vertebrate hosts are primarily fish, although they are also reported from amphibians, reptiles, trematodes, mollusks, birds and mammals. Invertebrate hosts include annelids and bryozoans. Most myxozoans are not overtly pathogenic to fish hosts, but some are responsible for severe economic losses in fisheries and aquaculture. In both scenarios, the interaction between the parasite and the host immune system is key to explain such different outcomes of this relationship. Innate immune responses contribute to the resistance of certain fish strains and species, and the absence or low levels of some innate and regulatory factors explain the high pathogenicity of some infections. In many cases, immune evasion explains the absence of a host response and allows the parasite to proliferate covertly during the first stages of the infection. In some infections, the lack of an appropriate regulatory response results in an excessive inflammatory response, causing immunopathological consequences that are worse than inflicted by the parasite itself. This review will update the available information about the immune responses against Myxozoa, with special focus on T and B lymphocyte and immunoglobulin responses, how these immune effectors are modulated by different biotic and abiotic factors, and on the mechanisms of immune evasion targeting specific immune effectors. The current and future design of control strategies for myxozoan diseases is based on understanding this myxozoan-fish interaction, and immune-based strategies such as improvement of innate and specific factors through diets and additives, host genetic selection, passive immunization and vaccination, are starting to be considered.

scholarly journals How alkaline compounds control atmospheric aerosol acidity

2020 ◽  
Author(s):  
Vlassis A. Karydis ◽  
Alexandra P. Tsimpidi ◽  
Andrea Pozzer ◽  
Jos Lelieveld
Keyword(s):  
Public Health ◽  
Atmospheric Aerosols ◽  
Climate Model ◽  
Control Strategies ◽  
Global Scale ◽  
Cloud Formation ◽  
Mass Composition ◽  
Aerosol Acidity ◽  
Pollutant Deposition ◽  
Particulate Mass

Abstract. The acidity of atmospheric aerosols regulates the particulate mass, composition and toxicity, and has important consequences for public health, ecosystems and climate. Despite these broad impacts, the global distribution and evolution of aerosol acidity are unknown. We used the particular, comprehensive atmospheric multiphase chemistry – climate model EMAC to investigate the main factors that control aerosol acidity, and uncovered remarkable variability and unexpected trends during the past 50 years in different parts of the world. We find that alkaline compounds, notably ammonium, and to a lesser extent crustal cations, buffer the aerosol pH on a global scale. Given the importance of aerosols for the atmospheric energy budget, cloud formation, pollutant deposition and public health, alkaline species hold the key to control strategies for air quality and climate change.

Mega Events and Their Effect on Mesoeconomics

2021 ◽  
pp. 208-230
Author(s):  
Teodora Kiryakova-Dineva ◽  
Vyara Kyurova ◽  
Yana Chankova
Keyword(s):  
Economic Activity ◽  
Interdisciplinary Research ◽  
Social Economic ◽  
Black Box ◽  
Scientific Investigation ◽  
Mega Events ◽  
Micro Level ◽  
Mega Event

The chapter proposes an analysis that claims the importance of phenomena successfully revealed only in view of mesoeconomics. The authors argue that the economic processes in the field of organizing events should not be conceived merely as resulting from macro- and micro-level relationships but rather as resulting from relationships on mesoeconomic level (where a large number of unresolved and unexplored issues still exist), discussed by the authors in terms of the black box relationships on the mesoeconomic level. The main aim of this study is to investigate a specific mega event so as to trace and analyze the roles of the operators at the three levels of social-economic activity, and finally to identify the specific roles of the operators functioning at the mesoeconomic level. Making up a small part of scientific investigation in interdisciplinary research, the chapter proposes further perspectives for a proper application of mesoeconomics when discussing issues bridging micro-economics and macro-economics.

scholarly journals Key Factors of Precipitation Stable Isotope Fractionation in Central-Eastern Africa and Central Mediterranean

Geosciences ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 337 ◽  
Author(s):  
Charles M. Balagizi ◽  
Marcello Liotta
Keyword(s):  
Isotope Fractionation ◽  
Hydrological Cycle ◽  
Global Scale ◽  
Vapor Condensation ◽  
Eastern Africa ◽  
Tropical Region ◽  
Central Mediterranean ◽  
Mild Winter ◽  
Stable Isotope Fractionation ◽  
Central Eastern

The processes of isotope fractionation in the hydrological cycle naturally occur during vapor formation, vapor condensation, and moisture transportation. These processes are therefore dependent on local and regional surface and atmospheric physical features such as temperature, pressure, wind speed, and land morphology, and hence on the climate. Because of the strong influence of climate on the isotope fractionation, latitudinal and altitudinal effects on the δ18O and δ2H values of precipitation at a global scale are observed. In this study, we present and compare the processes governing precipitation isotope fractionation from two contrasting climatic regions: Virunga in Central-Eastern Africa and the Central Mediterranean (Stromboli and Sicily, Italy). While Virunga is a forested rainy tropical region located between Central and Eastern Africa, the Mediterranean region is characterized by a rainy mild winter and a dry hot summer. The reported δ18O and δ2H dataset are from precipitation collected on rain gauges sampled either on a monthly or an approximately bimonthly basis and published in previous papers. Both regions show clearly defined temporal and altitudinal variations of δ18O and δ2H, depending on precipitation amounts. The Central Mediterranean shows a clear contribution of local vapor forming at the sea–air interface, and Virunga shows a contribution from both local and regional vapor. The vapor of Virunga is from two competing sources: the first is the continental recycled moisture from soil/plant evaporation that dominates during the rainy season, and the second is from the East African Great Lakes evaporation that dominates during the dry season.

Studies on the origin, evolution and distribution of the Gramineae. I. The tribe Andropogoneae

1958 ◽  
Vol 6 (2) ◽  
pp. 116 ◽  
Author(s):  
W Hartley
Keyword(s):  
Climatic Factors ◽  
Western Hemisphere ◽  
Western India ◽  
High Concentration ◽  
Cytological Evidence ◽  
Origin And Evolution ◽  
Eastern Hemisphere ◽  
Winter Temperatures ◽  
The Tropics ◽  
World Distribution

From a study of the grass flora of some 300 regions, a world distribution map of the grass tribe, Andropogoneae, has been prepared. This map shows that the Indo-Malaysian region is relatively rich in species of the tribe, with zones of high concentration in western India and in southern Indonesia. The relative species density falls off rapidly in passing from the tropical to the temperate zones, and is lower in the western than in the eastern hemisphere. Climatic factors are of major importance in determining the distribution pattern. Winter temperatures are of special significance in temperate regions, while there is a striking relationship between high midsummer rainfall and relative abundance of species of Andropogoneae in the tropics and subtropics. In general, the geographical survey supports conclusions drawn from taxonomic and cytological evidence regarding the origin and evolution of the tribe, but with greater emphasis on climate as a significant factor. The Andropogoneae have had a long evolutionary history in the eastern hemisphere, but have spread more recently to the western hemisphere, where they have not yet attained their full development.

The Wellcome Trust Lecture: Infection and disease in lymphatic filariasis: an immunological perspective

Parasitology ◽  
1992 ◽  
Vol 104 (S1) ◽  
pp. S71-S79 ◽  
Author(s):  
E. A. OtteSen
Keyword(s):  
Immune Responses ◽  
Lymphatic Filariasis ◽  
Clinical Manifestations ◽  
Genetic Determination ◽  
Inflammatory Reactions ◽  
Alternative Pathways ◽  
Immunodeficient Mice ◽  
Parasite Antigen ◽  
Immunological Responses ◽  
Asymptomatic Patients

SUMMARYThe basic tenet of the immunological perspective of fuiarial disease is that differential immune responsiveness among individuals exposed to infection results in the different clinical manifestations that develop. The mechanisms involved in this differential responsiveness appear to reflect different T-cell cytokine response patterns. Asymptomatic patients with the clinically silent presentation of ‘asymptomatic microfilaraemia’, who have been previously described as being ‘immunosuppressed’ with respect to their generating pro-inflammatory (Th1-type) immune responses to parasite antigen, are now recognized to be fully responsive to parasite antigen but to produce cytokines and mediators that have primarily anti-inflammatory (Th2-like) effects. Studies with immunodeficient mice have indicated the existence of two alternative pathways to the development of lymphatic pathology: one dependent on the induction of inflammatory reactions by the host immune response, the other entirely independent of the immune system and reflecting the direct actions of the parasite or its products on the lymphatics. As histopathology of affected human lymphatics is consistent with this hypothesis, it may be that the lymphatic pathology seen normally in the amicrofilaraemic, highly immunoresponsive infected patients derives from inflammation induced by immune responses to parasite antigen, whereas the lymphatic pathology sometimes seen coexisting with the ‘immunosuppressed’ state of asymptomatic microfilaraemia actually reflects lymphatic damage that is not immunologically mediated. Though little information exists about the ‘natural history’ of lymphatic filariasis, there is no evidence for an inevitable progression from one clinical form to another. Instead, there appears to be a definite plasticity in the response that depends on prior (? pre-natal) and current exposure to the parasite as well as on the immunomodulatory effects it induces. This plasticity does not appear to be complete, however, as there is no evidence that a chronically infected host who has developed strong pro-inflammatory immune responses can subsequently become sufficiently ‘down-regulated’ to support an asymptomatic microfilaraemia type of infection. Another possible constraint to the plasticity of the clinical and immunological responses may be the genetic determination of certain unusual syndromes, such as tropical pulmonary eosinophilia or TPE, though this hypothesis remains to be proven.

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