scholarly journals Effects of environmental parameters on chytrid infection prevalence of four marine diatoms: a laboratory case study

2017 ◽  
Vol 60 (4) ◽  
Author(s):  
Bettina Scholz ◽  
Wim Vyverman ◽  
Frithjof C. Küpper ◽  
Halldór G. Ólafsson ◽  
Ulf Karsten
Keyword(s):  
Environmental Factors ◽  
Host Species ◽  
Environmental Parameters ◽  
Coastal Areas ◽  
Marine Diatom ◽  
Infection Prevalence ◽  
Marine Diatoms ◽  
North West ◽  
Infection Susceptibility

AbstractThe influence of environmental factors on the infection susceptibility of four different marine diatom host species to chytrid infection was tested under laboratory conditions, using host and parasite isolates obtained from diverse coastal areas in north-west Iceland in 2015. Specifically, a total of 120 monoclonal marine diatom host cultures of

scholarly journals Predicting the Presence of Leptospires in Rodents from Environmental Indicators Opens Up Opportunities for Environmental Monitoring of Human Leptospirosis

2021 ◽  
Vol 13 (2) ◽  
pp. 325
Author(s):  
Leon Biscornet ◽  
Christophe Révillion ◽  
Sylvaine Jégo ◽  
Erwan Lagadec ◽  
Yann Gomard ◽  
...  
Keyword(s):  
Infectious Disease ◽  
Environmental Factors ◽  
Control Strategies ◽  
Sampling Site ◽  
Rattus Rattus ◽  
Environmental Parameters ◽  
Environmental Indicators ◽  
Small Island ◽  
Urban Landscapes ◽  
Infection Prevalence

Leptospirosis, an environmental infectious disease of bacterial origin, is the infectious disease with the highest associated mortality in Seychelles. In small island territories, the occurrence of the disease is spatially heterogeneous and a better understanding of the environmental factors that contribute to the presence of the bacteria would help implement targeted control. The present study aimed at identifying the main environmental parameters correlated with animal reservoirs distribution and Leptospira infection in order to delineate habitats with highest prevalence. We used a previously published dataset produced from a large collection of rodents trapped during the dry and wet seasons in most habitats of Mahé, the main island of Seychelles. A land use/land cover analysis was realized in order to describe the various environments using SPOT-5 images by remote sensing (object-based image analysis). At each sampling site, landscape indices were calculated and combined with other geographical parameters together with rainfall records to be used in a multivariate statistical analysis. Several environmental factors were found to be associated with the carriage of leptospires in Rattus rattus and Rattus norvegicus, namely low elevations, fragmented landscapes, the proximity of urbanized areas, an increased distance from forests and, above all, increased precipitation in the three months preceding trapping. The analysis indicated that Leptospira renal carriage could be predicted using the species identification and a description of landscape fragmentation and rainfall, with infection prevalence being positively correlated with these two environmental variables. This model may help decision makers in implementing policies affecting urban landscapes and/or in balancing conservation efforts when designing pest control strategies that should also aim at reducing human contact with Leptospira-laden rats while limiting their impact on the autochthonous fauna.

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.

scholarly journals SPATIO-STATISTICAL MODELING OF HUMAN BRUCELLOSIS USING ENVIRONMENTAL PARAMETERS: A CASE STUDY OF NORTHERN IRAN

2019 ◽  
Vol XLII-4/W18 ◽  
pp. 969-973
Author(s):  
N. Seyedalizadeh ◽  
A. A. Alesheikh ◽  
M. Ahmadkhani
Keyword(s):  
Public Health ◽  
Environmental Factors ◽  
Environmental Parameters ◽  
Management Plan ◽  
Decision Makers ◽  
Human Brucellosis ◽  
Northern Iran ◽  
The Public ◽  
Control And Management

Abstract. Brucellosis is one of the most important zoonotic diseases which is endemic in Iran. This disease is considered a significant hazard to citizens’ health and imposes heavy economic burdens, hence, requires a thorough control and management plan. The aims of this study are identifying the areas having the highest risk of brucellosis, as well as discovering the contributing environmental factors. The maximum entropy (MaxEnt) method was used to model the probability of brucellosis in Golestan, Mazandaran, and Guilan provinces. The possible contribution of 12 environmental parameters in this disease was also measured using the Jackknife method. The results showed that the highest risk of brucellosis is located in southern Golestan, East, and West of Mazandaran, and south of Guilan province, and moisture, slope, vegetation and elevation are the most effective environmental factors on the spatial distribution of the disease. In addition, the probability of the disease in northern Iran increases from west to east. These findings could assist the public health managers and decision-makers in organizing a more efficient public health system.

scholarly journals Epipelic and epipsammic microalgae responses to environmental parameters: the Black Sea case study (the Gulf of Odesa, Ukraine)

Algologia ◽  
2021 ◽  
Vol 31 (3) ◽  
pp. 228-248
Author(s):  
A.O. Snigirova ◽  
◽  
S.O. Silantyev ◽  
O.Yu. Goncharov ◽  
O.V. Koshelev ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Black Sea ◽  
Organic Nitrogen ◽  
Environmental Parameters ◽  
Algal Community ◽  
The Black Sea ◽  
Grain Composition ◽  
Black Sea Region ◽  
Priority Factor

In spite of relatively frequent studies of the influence of environmental parameters on the microalgae communities, the processes that occur in the sandy littoral in the Black Sea region seeks for additional research. The aim of this paper was to range the environmental factors in relation to algal sandy communities and show the interaction between microalgae abundance and 14 environmental factors during field multifactoral experiment: 5 parameters describing sand grain composition, nutrients, temperature and salinity of water, hydrodynamics and water toxicity. The species composition of epipelic and epipsammic microalgae and their distribution in different habitats in summer and autumn periods were analysed. The priority factor for psammon algal community in any season is size of sand grains and siliceous oxide. Other variables depend on the season: while in summer, mineral nitrogen (nitrates and nitrites) effects the microphytes more intensively than others, in autumn it is replaced by organic nitrogen and silty fraction.

PERSIAN GARDENS IN COLD AND DRY CLIMATE: A CASE STUDY OF TABRIZ’S HISTORICAL GARDENS

2016 ◽  
Vol 10 (3) ◽  
pp. 193
Author(s):  
Ahad Nejad Ebrahimi ◽  
Farnaz Nazarzadeh ◽  
Elnaz Nazarzadeh
Keyword(s):  
Comparative Study ◽  
Water Supply ◽  
Field Study ◽  
Cold Climate ◽  
Natural Substrate ◽  
Garden Design ◽  
Climate Conditions ◽  
North West ◽  
Special Expertise

Throughout history, gardens and garden designing has been in the attention of Persian architects who had special expertise in the construction of gardens. The appearance of Islam and allegories of paradise taken from that in Koran and Saints’ sayings gave spirituality to garden construction. Climate conditions have also had an important role in this respect but little research has been done about it and most of the investigations have referred to spiritual aspects and forms of garden. The cold and dry climate that has enveloped parts of West and North West of Iran has many gardens with different forms and functions, which have not been paid much attention to by studies done so far. The aim of this paper is to identify the features and specifications of cold and dry climate gardens with an emphasis on Tabriz’s Gardens.  Due to its natural and strategic situation, Tabriz has always been in the attention of governments throughout history; travellers and tourists have mentioned Tabriz as a city that has beautiful gardens. But, the earthquakes and wars have left no remains of those beautiful gardens. This investigation, by a comparative study of the climates in Iran and the effect of those climates on the formation of gardens and garden design, tries to identify the features and characteristics of gardens in cold and dry climate. The method of study is interpretive-historical on the basis of written documents and historic features and field study of existing gardens in this climate. The results show that, with respect to natural substrate, vegetation, the form of water supply, and the general form of the garden; gardens in dry and cold climate are different from gardens in other climates.

TIDAL FLATS DEVELOPMENT MODEL OF COASTAL AREAS —A CASE STUDY OF YANCHENG CHINA

2020 ◽  
pp. 25-28
Author(s):  
XU HUILIN ◽  
CHEN HUIHUI ◽  
ZHOU WEI ◽  
FU JIAJIA
Keyword(s):  
Coastal Areas ◽  
Tidal Flats ◽  
Development Model ◽  
Ecological Environment ◽  
Present Stage ◽  
Important Resource ◽  
Modern Agriculture ◽  
Dynamic Growth

Tidal fats resources is an important resource in coastal areas of China, which shows a trend of dynamic growth. Ratonal development and efectve utlizaton of tdal fats resources can alleviate the contradicton between more people and less land in China, and is of great signifcance to the development of coastal economy and the protecton of ecological environment in China. Taking Yancheng Tidal Flats of Coastal Areas as an example, analyzes the present situaton of development and utlizaton and the existng problems at the present stage. Relying on the existng industrial foundaton, this paper puts forward the development and utlizaton model of strengthening the constructon of port-neighboring industry, towns and ecological leisure tourism on the basis of modern agriculture

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