Cyclic epidemics and extreme outbreaks induced by hydro-climatic variability and memory

A minimalist model of ecohydrologic dynamics is coupled to the well-known susceptible–infected–recovered epidemiological model to explore hydro-climatic controls on infection dynamics and extreme outbreaks. The resulting HYSIR model reveals the existence of a noise-induced bifurcation producing oscillations in infection dynamics. Linearization of the governing equations allows for an analytic expression for the periodicity of infections in terms of both epidemiological (e.g. transmission and recovery rate) and hydrologic (i.e. soil moisture decay rate or memory) parameters. Numerical simulations of the full stochastic, nonlinear system show extreme outbreaks in response to particular combinations of hydro-climatic conditions, neither of which is extreme per se , rather than a single major climatic event. These combinations depend on the assumed functional relationship between the hydrologic variables and the transmission rate. Our results emphasize the importance of hydro-climatic history and system memory in evaluating the risk of severe outbreaks.

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Infection dynamics and persistence of hepatitis E virus on pig farms – a review

Porcine Health Management ◽

10.1186/s40813-021-00189-z ◽

2021 ◽

Vol 7 (1) ◽

Author(s):

M. Meester ◽

T. J. Tobias ◽

M. Bouwknegt ◽

N. E. Kusters ◽

J. A. Stegeman ◽

...

Keyword(s):

Risk Factors ◽

Hepatitis E Virus ◽

Risk Mitigation ◽

Transmission Rate ◽

Hepatitis E ◽

Main Body ◽

Genotype 3 ◽

Infection Dynamics ◽

Pig Farms ◽

Slaughter Pigs

Abstract Background Hepatitis E virus (HEV) genotype 3 and 4 is a zoonosis that causes hepatitis in humans. Humans can become infected by consumption of pork or contact with pigs. Pigs are the main reservoir of the virus worldwide and the virus is present on most pig farms. Main body Though HEV is present on most farms, the proportion of infected pigs at slaughter and thus the level of exposure to consumers differs between farms and countries. Understanding the cause of that difference is necessary to install effective measures to lower HEV in pigs at slaughter. Here, HEV studies are reviewed that include infection dynamics of HEV in pigs and on farms, risk factors for HEV farm prevalence, and that describe mechanisms and sources that could generate persistence on farms. Most pigs become infected after maternal immunity has waned, at the end of the nursing or beginning of the fattening phase. Risk factors increasing the likelihood of a high farm prevalence or proportion of actively infected slaughter pigs comprise of factors such as farm demographics, internal and external biosecurity and immunomodulating coinfections. On-farm persistence of HEV is plausible, because of a high transmission rate and a constant influx of susceptible pigs. Environmental sources of HEV that enhance persistence are contaminated manure storages, water and fomites. Conclusion As HEV is persistently present on most pig farms, current risk mitigation should focus on lowering transmission within farms, especially between farm compartments. Yet, one should be aware of the paradox of increasing the proportion of actively infected pigs at slaughter by reducing transmission insufficiently. Vaccination of pigs may aid HEV control in the future.

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Geologic-Climatic Dating in the West

American Antiquity ◽

10.2307/277066 ◽

1955 ◽

Vol 20 (4Part1) ◽

pp. 317-335 ◽

Cited By ~ 130

Author(s):

Ernst Antevs

Keyword(s):

Climatic Conditions ◽

Western United States ◽

The West ◽

Geological Processes ◽

Relative Chronology ◽

Geological Features ◽

Climatic History ◽

The Relationship ◽

Arid And Semiarid ◽

Made In

Geologic-Climatic dating of archaeological finds in the arid and semiarid western United States is based on geology, on the relationship between moisture, vegetation, and geological processes, and on climatic history. The procedure of dating includes 4 main steps, namely, (1) study of beds and geological features, (2) climatic interpretation of beds and features, (3) assignment of the bed with the human record to a particular regional climatic age or phase, and (4) correlation of the regional relative chronology with a dated climatic history. The geological study of the site includes texture, structure, and appearance of the beds or terrace deposits, their modes and conditions of formation, their sequence, fossils, and artifacts, the soil zones, caliche incrustations, and erosions. The climatic interpretation of the beds and features is made in conformity with the delicate regional relationship between climatic conditions and changes and geological processes and deposits.

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Record of the Climatic Variability and the Sedimentary Dynamics during the Last Two Millennia at Sebkha Dkhila, Eastern Tunisia

ISRN Geology ◽

10.1155/2013/936198 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 3

Author(s):

Elhoucine Essefi ◽

Jamel Touir ◽

Mohamed Ali Tagorti ◽

Chokri Yaich

Keyword(s):

Little Ice Age ◽

Climatic Variability ◽

Low Frequency ◽

Climatic Conditions ◽

Ice Age ◽

Global Changes ◽

Medieval Climatic Anomaly ◽

Grey Scale ◽

Sedimentary Dynamics ◽

The Last Two Millennia

This paper aimed to study the record of the climatic variability during the last two millennia within the sebkha of Dkhila. Six climatic stages were recognized along the 104 cm core: the Warming Present (WP), the Late Little Ice Age (Late LIA), the Early Little Ice Age (ELIA), the Medieval Climatic Anomaly (MCA), the Dark Age (DA), and the Roman Warm Period (RWP). The WP stretches along the uppermost 1 cm with a high grey scale as sign of a dry climate. The Late LIA is located between 1 cm and 6 cm. The ELIA is located between 6 cm and 40 cm. The MCA spanning from 40 cm to 72 cm is marked by a sharp increase of the GS revealing a wet period. The DA appears along the part between 72 cm and 84 cm; a shift from light to dark sediments is recorded. The RWP appears between 84 cm and 104 cm. Based on the grain size distribution, two low frequency cycles were identified indicating radical global changes of climatic conditions, the differential tectonics, and the groundwater fluctuations. On the other hand, high frequency cycles indicate local modifications of the climatic conditions.

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Potential for transmission of Stenocarpella macrospora from inoculated seeds to maize plants grown under controlled conditions

Journal of Seed Science ◽

10.1590/2317-1545v32n2904 ◽

2014 ◽

Vol 36 (2) ◽

pp. 154-161 ◽

Cited By ~ 5

Author(s):

Carolina da Silva Siqueira ◽

José da Cruz Machado ◽

Ellen Noly Barrocas ◽

Mirella Figueiró de Almeida

Keyword(s):

Transmission Rate ◽

Climatic Conditions ◽

Inoculum Potential ◽

Ear Rot ◽

Total Rate ◽

Maize Cultivars ◽

Maize Seeds ◽

Two Temperatures ◽

Maize Plants ◽

Biological Methods

Maize seeds infected by Stenocarpella macrospora can cause stalk and ear rot and leaf spot. Transmission of this pathogen through seeds may vary according to the cultivar, climatic conditions, and virulence of the pathogen among other factors. The aim of this study was to assess the transmission rate of S. macrospora from seeds of the maize cultivars C1-RB9308YG and C2-RB9108 using artificially infected seeds grown under two temperatures (20 ºC and 25 ºC). Seeds were inoculated by the osmotic conditioning method for 24 h (inoculum potential - P1), 48 h (P2), 72 h (P3) and 96 h (P4). After inoculation, 25 seeds were distributed individually in plastic cups with substrate, with 4 replicates per treatment. At the end of twenty-eight days of daily assessments, all plants were analyzed for the presence of the pathogen by biological methods, and some were sampled at random and analyzed Bio-PCR. The maximum percentages of dead seeds/seedlings in pre-emergence were 74.5% and 82.5% for P3 and P4, respectively. The highest total rate of transmission of the pathogen under study was 85.8% for seeds of the cultivar C1 at the highest inoculum potential (P4), grown at the temperature of 20 ºC.

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High resistance to climatic variability in a dominant tundra shrub species

PeerJ ◽

10.7717/peerj.6967 ◽

2019 ◽

Vol 7 ◽

pp. e6967 ◽

Cited By ~ 2

Author(s):

Victoria T. González ◽

Mikel Moriana-Armendariz ◽

Snorre B. Hagen ◽

Bente Lindgård ◽

Rigmor Reiersen ◽

...

Keyword(s):

Climate Change ◽

High Resistance ◽

Climatic Variability ◽

Growing Season ◽

Climatic Conditions ◽

Vegetative Cover ◽

Growth And Survival ◽

Growing Season Length ◽

Temperature And Precipitation ◽

Precipitation Regimes

Climate change is modifying temperature and precipitation regimes across all seasons in northern ecosystems. Summer temperatures are higher, growing seasons extend into spring and fall and snow cover conditions are more variable during winter. The resistance of dominant tundra species to these season-specific changes, with each season potentially having contrasting effects on their growth and survival, can determine the future of tundra plant communities under climate change. In our study, we evaluated the effects of several spring/summer and winter climatic variables (i.e., summer temperature, growing season length, growing degree days, and number of winter freezing days) on the resistance of the dwarf shrub Empetrum nigrum. We measured over six years the ability of E. nigrum to keep a stable shoot growth, berry production, and vegetative cover in five E. nigrum dominated tundra heathlands, in a total of 144 plots covering a 200-km gradient from oceanic to continental climate. Overall, E. nigrum displayed high resistance to climatic variation along the gradient, with positive growth and reproductive output during all years and sites. Climatic conditions varied sharply among sites, especially during the winter months, finding that exposure to freezing temperatures during winter was correlated with reduced shoot length and berry production. These negative effects however, could be compensated if the following growing season was warm and long. Our study demonstrates that E. nigrum is a species resistant to fluctuating climatic conditions during the growing season and winter months in both oceanic and continental areas. Overall, E. nigrum appeared frost hardy and its resistance was determined by interactions among different season-specific climatic conditions with contrasting effects.

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Considering Harmful Algal Blooms

10.5772/intechopen.94771 ◽

2020 ◽

Author(s):

Ruby E. Jalgaonwala

Keyword(s):

Climate Change ◽

Social Life ◽

Harmful Algal Blooms ◽

Algal Blooms ◽

Marine Organism ◽

Harmful Algal Bloom ◽

Climatic Variability ◽

Climatic Conditions ◽

Water Ecosystem ◽

Negative Effect

Problematic harmful algal bloom is wide and tenacious, upsetting estuaries, coasts, and freshwaters system throughout the ecosphere, alongside disturbing human health, social life as well as national economy. Particular environmental factors supports growth of algal blooms, temperature always is significant when speaking about water-ecosystem. Disparity in temperature also found to affect the interaction of physical, chemical and biological parameters so it is equally imperative to consider effects of climate change, as change in climatic conditions supports unwanted growth of algae. Also inconsistency in climate equally contributes to the apparent increases of HAB, therefore effects of climate change needs to be totally comprehended along with development of the risk assessments and effective management of HABs. Increased HAB activities have a direct negative effect on ecosystems and they can frequently have a direct commercial impact on aquaculture, depending on the type of HAB. Causing economic impact also, as there is still insufficient evidence to resolve this problem. Therefore this chapter considers the effects of past, present and future climatic variability on HABs along with impacts of toxins release by them, on marine organism as well as human beings correspondingly, mitigation of HAB with help of suitable biological agents recognized.

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Modelling the in vitro pre-infection dynamics of Colletotrichum spp. isolated from yellow passion fruit in function of environmental variables

10.1101/781963 ◽

2019 ◽

Author(s):

Karinna Vieira Chiacchio Velame ◽

Hermes Peixoto Santos Filho ◽

Adelise de Almeida Lima ◽

Carlos Augusto Dórea Bragança ◽

Francisco Ferraz Laranjeira

Keyword(s):

Environmental Variables ◽

Climatic Conditions ◽

Passion Fruit ◽

Yield Reduction ◽

Post Harvest ◽

Infection Dynamics ◽

Mycelia Growth ◽

Wetness Period ◽

Yellow Passion Fruit

AbstractBrazil is the largest world producer of yellow passion fruit, but the mean yield (14.3t.ha-1) is less than half the potential of the crop. Part of this difference can be explained by plant health problems, including anthracnose caused by Colletotrichum spp. In regions with favorable climatic conditions, anthracnose can be a factor of significant yield reduction, but these regions have not yet been zoned. The objective of this study was to model the pre-infection dynamics of the fungus. The influence of temperature and photoperiod was studied on mycelia growth, sporulation and conidia germination. Mathematical models were fitted to the results and the optima for the environmental variables were estimated. The maximum mycelia growth was estimated to occur at 26.5°C. Between 24.5°C and 28.5°C the fungus grew from 95% to 100% of the estimated maximum. Temperatures below 13°C or above 34°C were harmful to mycelia growth. Temperatures over 26°C were the most favorable to sporulation while below 13°C sporulation was only 5% of the maximum. Optimum germination occurred between 25°C and 29°C with the ideal wetness period between 11h and 13h. These results can be used as a basis for zoning the risk of anthracnose occurrence in passion fruit producing regions.Significance and Impact of the StudyMany diseases affect the yellow passion fruit crop, limiting its yield; among them anthracnose, caused by Colletotrichum spp. The disease occurs in both field (leaf and stem symptoms) and post-harvest (fruits) conditions. Understanding the role environmental conditions play in the biological cycle of such diseases is essential for developing management strategies. By modelling mycelial growth, spore production and spore germination of Colletotrichum spp. as affected by temperature, photoperiod and wetness period, it was possible to characterize the pathogen’s pre-infectional dynamics. The results should be used as a first approximation to estimate the risk of anthracnose occurrence in pre- or post-harvest.

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Late-Holocene climatic record from a glacial lake in Ladakh range, Trans-Himalaya, India

The Holocene ◽

10.1177/0959683620908660 ◽

2020 ◽

Vol 30 (7) ◽

pp. 1029-1042 ◽

Cited By ~ 3

Author(s):

Binita Phartiyal ◽

Randheer Singh ◽

Priyanka Joshi ◽

Debarati Nag

Keyword(s):

Climatic Variability ◽

Organic Content ◽

Climatic Conditions ◽

Water Levels ◽

Warm Climate ◽

Nw Himalaya ◽

Reducing Conditions ◽

Continuous Sedimentation ◽

Proglacial Lake ◽

Arid Desert

A multi-proxy study using mineral magnetism, sediment texture, total organic content, palynofacies and diatoms was conducted in one of the highest proglacial lake situated at North Pulu (5098 m a.s.l.) of Ladakh sector of NW Himalaya – a high-altitude cold arid desert. This study presents climatic variations that occurred between 5412 and 419 cal. yr BP (14C AMS chronology). Directly recharged by meltwater from Khardung glacier, this proglacial lake provides a complete record of past climatic variability due to continuous sedimentation and this attribute makes it an exceptionally important geochronological archive for climatic studies. This first high-resolution palaeolimnology record from Karakoram Himalayas shows intermittent warm and cold periods in which the cold events are short but sudden events recorded at 5700, 4600, 4400, 4200, 3800, 3500, 3000, 1800–1700, 1200, 910, 840 and 770–710 cal. yr BP. Between 5412 and 4840 cal. yr BP, an oxic lake condition existed with freeze–thaw action, prominent weathering, more sediment generation and less organic productivity. The following period till 4410 cal. yr BP was cold and dry, a transition phase to the next warmer phase. Between 4410 and 2064 cal. yr BP, climate ameliorated to somewhat moderate warm climate and relatively high lake levels. Glacial melting due to a warm climate resulted in high TOC%, and well-preserved OM indicating reducing conditions in the lake system. From 2064 to 1711 cal. yr BP cold conditions and from 1272 to 1182 cal. yr BP warmer conditions are seen with large appearance in Amphora ovalis indicating increased nutrients input and moderate water levels. This was followed by warmer climatic conditions between 1182 and 958 cal. yr BP. LIA in the region is experienced between 958 and 644 cal. yr BP with anoxic condition. Between 644 and 419 cal. yr BP, climatic condition was again warmer comparatively. However, this warming was not so severe and only had a regional impact.

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The Toledo Mountains: A Resilient Landscape and a Landscape for Resilience? Hazards and Strategies in a Mid-Elevation Mountain Region in Central Spain

Quaternary ◽

10.3390/quat2040035 ◽

2019 ◽

Vol 2 (4) ◽

pp. 35 ◽

Cited By ~ 1

Author(s):

Reyes Luelmo-Lautenschlaeger ◽

Sebastián Pérez-Díaz ◽

Olivier Blarquez ◽

César Morales-Molino ◽

José Antonio López-Sáez

Keyword(s):

Climatic Variability ◽

Central Area ◽

Climatic Conditions ◽

Mediterranean Vegetation ◽

Ice Age ◽

Mountain Range ◽

Taxus Baccata ◽

Central Spain ◽

Ilex Aquifolium ◽

Original Distribution

The Toledo Mountains are a mid-elevation mountain range that separates the Tagus and Guadiana basins in the central area of the Iberian Peninsula. The location of these mountains allows the development of typical Mediterranean vegetation with some Atlantic influence. Consequently, typical broadleaved evergreen Mediterranean vegetation currently dominates the regional landscape, with the remarkable presence of more mesophilous species in sheltered and more humid microsites such as gorges (e.g., Prunus lusitanica, Taxus baccata, Ilex aquifolium) and mires/bogs (e.g., Betula pendula susbp. fontqueri, Erica tetralix, Myrica gale). Palaeoecological studies in these mountains are essential to understand the long-term ecology and original distribution of these valuable communities and are key to assess their resilience. Understanding the hazards and opportunities faced in the past by the plant communities of the Toledo Mountains is necessary to enhance the management and protection of those species currently threatened. This study focuses on El Perro mire, a peatland on the southern Toledo Mountains (central Spain) where climatic variability has played a major role in landscape dynamics at multi-decadal to millennial timescales. Climatic events such as the 4.2 ka cal. Before Present (BP) or the Little Ice Age triggered relevant landscape changes such as the spread and latter decline of birch and hazel forests. Human communities also seemed to be affected by these events, as their resilience was apparently jeopardized by the new climatic conditions and they were forced to find new strategies to cope with the new scenarios.

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Variability to sedimentary dynamics and climatic conditions during the last two millennia at sebkha Souassi in eastern Tunisia

Papers on Global Change IGBP ◽

10.2478/igbp-2013-0001 ◽

2013 ◽

Vol 20 (1) ◽

Author(s):

Elhoucine Essefi ◽

Hayet Ben Jmaa ◽

Jamel Touir ◽

Mohamed Ali Tagortig ◽

Chokri Yaicha

Keyword(s):

Grain Size ◽

Size Distribution ◽

Grain Size Distribution ◽

Little Ice Age ◽

Climatic Variability ◽

Climatic Conditions ◽

Ice Age ◽

Global Changes ◽

Sedimentary Dynamics ◽

The Last Two Millennia

AbstractThis paper covers work intended to study the interplay of sedimentary dynamics and climatic variability over the last two millennia within Tunisia’s sebkha Souassi. Based on the Visual Core Description, and magnetic susceptibility, we date the core from sebkha Souassi to the last two millennia. Genetic grain-size distribution then provided a basis for the identification of six climatic stages, i.e. the Warming Present (WP), the Late Little Ice Age (Late LIA), the Early Little Ice Age (ELIA), the Medieval Climatic Anomaly (MCA), the Dark Ages (DA), and the Roman Warm Period (RWP). The WP stretches across the uppermost 3 cm, with a high grey scale indicating a dry climate. The Late LIA is located between 3 and 7 cm, and the ELIA between 7 and 28 cm. Intermediate values for GS indicate that this stage may be classified as moderate. The MCA spanning from 28 to 40 cm is marked by a sharp decrease in GS indicative of a wet period. The DA appear along the part between 40 and 79 cm, a shift from light to dark sediments being recorded. The RWP in turn appears between 79 and 114 cm. Based on the grain-size distribution, two low-frequency cycles were identified, indicating radical global changes in climatic conditions, differential tectonics and groundwater fluctuations. High-frequency cycles in turn attest to local modifications of climatic conditions.

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