scholarly journals Occurrence of Batrachochytrium dendrobatidis in Sweden: higher infection prevalence in southern species

2020 ◽  
Vol 140 ◽  
pp. 209-218
Author(s):  
S Meurling ◽  
S Kärvemo ◽  
N Chondrelli ◽  
M Cortazar Chinarro ◽  
D Åhlen ◽  
...  
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Egg Laying ◽  
Infection Prevalence ◽  
Chytrid Fungus ◽  
Generalist Species ◽  
Green Toad ◽  
Central Regions ◽  
Bombina Bombina ◽  
The Impact ◽  
Southern Species

The chytrid fungus Batrachochytrium dendrobatidis (Bd) has caused worldwide declines in amphibian populations. While Bd is widespread in southern and central Europe, its occurrence and distribution in northernmost Europe is mostly unknown. We surveyed for Bd in breeding anurans in Sweden by sampling 1917 amphibians from 101 localities and 3 regions in Sweden (southern, northern and central). We found that Bd was widespread in southern and central Sweden, occurring in all 9 investigated species and in 45.5% of the 101 localities with an overall prevalence of 13.8%. No infected individuals were found in the 4 northern sites sampled. The records from central Sweden represent the northernmost records of Bd in Europe. While the proportion of sites positive for Bd was similar between the southern and central regions, prevalence was much higher in the southern region. This was because southern species with a distribution mainly restricted to southernmost Sweden had a higher prevalence than widespread generalist species. The nationally red-listed green toad Bufotes variabilis and the fire-bellied toad Bombina bombina had the highest prevalence (61.4 and 48.9%, respectively). Across species, Bd prevalence was strongly positively, correlated with water temperature at the start of egg laying. However, no individuals showing visual signs of chytridiomycosis were found in the field. These results indicate that Bd is widespread and common in southern and central Sweden with southern species, breeding in higher temperatures and with longer breeding periods, having higher prevalence. However, the impact of Bd on amphibian populations in northernmost Europe remains unknown.

scholarly journals Impacts of thermal mismatches on chytrid fungus Batrachochytrium dendrobatidis prevalence are moderated by life stage, body size, elevation and latitude

2018 ◽  
Author(s):  
Jeremy M. Cohen ◽  
Taegan A. McMahon ◽  
Chloe Ramsay ◽  
Elizabeth A. Roznik ◽  
Erin L. Sauer ◽  
...  
Keyword(s):  
Body Size ◽  
Batrachochytrium Dendrobatidis ◽  
Global Climate ◽  
Global Analysis ◽  
Life Stage ◽  
Conservation Status ◽  
Amphibian Declines ◽  
Lower Latitude ◽  
Infection Prevalence ◽  
Chytrid Fungus

AbstractGlobal climate change is increasing the frequency of unpredictable weather conditions; however, it remains unclear how species-level and geographic factors, including body size and latitude, moderate impacts of unusually warm or cool temperatures on disease. Because larger hosts and lower-latitude hosts generally have slower acclimation times, we hypothesized that their disease susceptibility increases under “thermal mismatches”, or differences between baseline climate and the temperature during surveying. Here, we examined how thermal mismatches interact with body size, life stage, habitat, latitude, elevation, phylogeny, and IUCN conservation status to predict infection prevalence of the chytrid fungus Batrachochytrium dendrobatidis (Bd) in a global analysis of 38,967 amphibian hosts. As hypothesized, we found that the susceptibility of larger hosts and hosts from lower latitudes was strongly influenced by thermal mismatches. Furthermore, hosts of conservation concern are more susceptible than others following thermal mismatches, suggesting that thermal mismatches might have contributed to recent amphibian declines.Data Accessibility StatementShould the manuscript be accepted, the data supporting the results will be archived in an appropriate public repository such as Dryad or Figshare and the data DOI will be included at the end of the article.

scholarly journals Distribution and Genetic Diversity of the Amphibian Chytrid in Japan

2021 ◽  
Vol 7 (7) ◽  
pp. 522
Author(s):  
Koichi Goka ◽  
Jun Yokoyama ◽  
Atsushi Tominaga
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Limited Area ◽  
Infection Prevalence ◽  
Chytrid Fungus ◽  
Amphibian Species ◽  
Okinawa Island ◽  
Dna Variation ◽  
The Status ◽  
Long Time ◽  
Pcr Method

While research on frog chytrid fungus Batrachochytrium dendrobatidis (Bd), an infectious disease that threatens amphibian diversity, continues to advance worldwide, little progress has been made in Japan since around 2010. The reason for this is, which we pointed out in 2009, that the origin of frog chytrid fungus may be in the East Asian region, including Japan based on the Bd ITS-DNA variation, and as few cases of mass mortality caused by this fungus have been observed in wild amphibian populations in Japan, the interest of the Japanese government and the general public in Bd has waned. However, we believe that organizing the data obtained so far in Japan and distributing the status of frog chytrid fungus in Japan to the world will provide useful insight for future risk management of this pathogen. We collected more than 5500 swab samples from wild amphibians throughout Japan from 2009 to 2010. Then, we investigated the infection status using the Nested-PCR method. We sequenced the obtained DNA samples and constructed a maximum-parsimony (MP) tree to clarify the phylogenetic diversity of Bd. We detected Bd infection in 11 (nine native and two alien) amphibian species in Japan and obtained 44 haplotypes of Bd ITS-DNA. The MP tree showed a high diversity of Bd strains in Japan, suggesting that some strains belong to Bd-GPL and Bd-Brazil. Except for local populations of the Japanese giant salamanders Andrias japonicus in Honshu Island and the sword tail newts Cynops ensicauda in Okinawa Island, the Bd infection prevalence in native amphibian species was very low. The alien bullfrog Aquarana catesbeiana had high Bd infection rates in all areas where they were sampled. No Bd infection was detected in other native amphibians in the areas where giant salamanders, sword tail newts, and bullfrogs were collected, suggesting that many native amphibians are resistant to Bd infection. The sword tail newt of Okinawa Island had both the highest infectious incidence and greatest number of haplotypes. The giant salamanders also showed relatively high infection prevalence, but the infected strains were limited to those specific to this species. These two Caudata species are endemic to a limited area of Japan, and it was thought that they may have been refugia for Bd, which had been distributed in Japan Islands for a long time.

scholarly journals Infection patterns of the chytrid fungus, Batrachochytrium dendrobatidis, on anuran assemblages in agro-ecosystems from Buenos Aires Province, Argentina

2015 ◽  
Vol 14 (2) ◽  
pp. 113 ◽  
Author(s):  
M. Gabriela Agostini ◽  
Patricia A. Burrowes
Keyword(s):  
Land Use ◽  
Batrachochytrium Dendrobatidis ◽  
Buenos Aires ◽  
Agricultural Landscapes ◽  
Buenos Aires Province ◽  
Chytrid Fungus ◽  
Infection Level ◽  
Tissue Samples ◽  
High Prevalence ◽  
The Impact

Infection patterns of the chytrid fungus, Batrachochytrium dendrobatidis, on anuran assemblages in agro-ecosystems from Buenos Aires Province, Argentina. The disease chytridiomycosis, caused by the pathogenic chytrid fungus Batrachochytrium dendrobatidis (Bd), is linked to extinctions and declines of amphibians. Additionally, in the context of amphibian decline, the habitat loss related to agricultural landscapes is likely the single most important human activity affecting lowland amphibian populations. To assess the impact of anthropogenic land use on anuran response to Bd, infection patterns in several ponds from cultivated (CA) and uncultivated areas (UCA) were studied. Four anuran species (Rhinella fernandezae [Bufonidae]; juvenile and adult of Leptodactylus latrans [Leptodactylidae]; and the hylids Hypsiboas pulchellus and Pseudis minuta) were monitored and tissue samples were collected for Bd diagnosis and quantification. All species tested positive for Bd, but anurans inhabiting the UCA were twice more likely to be infected than those in the CA. Prevalence and infection level were significantly higher in the UCA, suggesting that vulnerability to Bd is associated with land use in agro-ecosystems. At the assemblage-level, the infection patterns also differed among species, and those with aquatic habitats (L. latrans and P. minuta) had high prevalence and infection levels of Bd. Juvenile stages of L. latrans had higher prevalence and infection level than adults in both study areas. This work contributes to our understanding of anthropogenic effects on host-pathogen relationships, particularly on the effect of Bd on anuran assemblages under different levels of agricultural impact.

Low infection prevalence of the amphibian chytrid fungus Batrachochytrium dendrobatidis (Chytridiomycetes: Rhizophydiales) in Cuba

2017 ◽  
Vol 38 (2) ◽  
pp. 243-249 ◽  
Author(s):  
Joana Sabino-Pinto ◽  
Molly C. Bletz ◽  
Manuel Iturriaga ◽  
Miguel Vences ◽  
Ariel Rodríguez
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Infection Prevalence ◽  
Chytrid Fungus ◽  
Population Declines ◽  
Amphibian Chytrid Fungus

The chytrid fungus Batrachochytrium dendrobatidis (Bd) is responsible for population declines and extinctions of amphibians worldwide. The distribution and prevalence of Bd in Cuba has remained unknown to date, with only a single report on its presence. We collected 182 samples from wild anuran populations across 21 species and 16 localities and tested for the presence of Bd using qPCRs. Only six Bd positive samples from four species were detected in three very close localities in Central Cuba. Bd prevalence was of 10-20% in the positive localities, and the island-wide prevalence was only 3.2%. These results indicate that Bd occurrence in Cuba might be concentrated in or even restricted to the central Guamuhaya Massif and call for increased conservation and monitoring efforts in these mountains along with additional sampling in areas and species not covered in this study.

How tourism industry agglomeration improves tourism economic efficiency?

2021 ◽  
pp. 135481662110091
Author(s):  
Zhoufei Li ◽  
Huiyue Liu
Keyword(s):  
Positive Impact ◽  
Regional Analysis ◽  
Tourism Industry ◽  
Scale Efficiency ◽  
Eastern Region ◽  
Location Quotient ◽  
Industry Agglomeration ◽  
Central Regions ◽  
National Perspective ◽  
The Impact

The agglomeration of the tourism industry has important effects on its efficiency. This article used panel data on the Chinese provincial tourism industry for the 2011–2016 period, applied the location quotient index and three-stage data envelopment analysis method to, respectively, measure the degree of agglomeration and efficiency, and explained the impact of agglomeration on tourism efficiency. The empirical results of this study indicate the following. (1) China’s tourism industry shows a trend towards agglomeration, revealing gradient differences where the highest degree of agglomeration is in the eastern region, followed by the western and central regions. (2) After eliminating random and environmental factors, the adjusted efficiencies are lower than the unadjusted efficiencies. The average overall tourism efficiency is higher in the eastern region than in the central and western regions. (3) From the national perspective, industrial agglomeration can significantly improve the overall efficiency (TE), pure technical efficiency (PTE), and scale efficiency of the tourism industry. (4) Based on regional analysis, the agglomeration of the eastern tourism industry can significantly enhance its TE and PTE. Agglomeration for the western area has a significant positive impact on PTE. There is no significant relationship between agglomeration and efficiency in the central region.

Evaluation of the Skin Peptide Defenses of the Oregon Spotted Frog Rana pretiosa Against Infection by the Chytrid Fungus Batrachochytrium dendrobatidis

2013 ◽  
Vol 39 (6) ◽  
pp. 797-805 ◽  
Author(s):  
J. Michael Conlon ◽  
Laura K. Reinert ◽  
Milena Mechkarska ◽  
Manju Prajeep ◽  
Mohammed A. Meetani ◽  
...  
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Chytrid Fungus ◽  
Rana Pretiosa

Prospective Assessment of Helicobacter Pylori Infection and Gastric Pathologies in Sidi Bel Abbes region, Western Algeria

2018 ◽  
Vol 7 (5) ◽  
pp. 217-224
Author(s):  
Zouaouia Chama ◽  
Khedoudj Kanoun ◽  
Fatima Zohra Elkadi ◽  
Kara Turqui Douidi ◽  
Noria Harir ◽  
...  
Keyword(s):  
Gastric Cancer ◽  
Helicobacter Pylori ◽  
Histological Study ◽  
Helicobacter Pylori Infection ◽  
University Hospital ◽  
Infection Prevalence ◽  
Gastric Diseases ◽  
Number Of Patients ◽  
H Pylori ◽  
The Impact

Helicobacter pylori infection concerns half of the world’s population, mainly in developing countries. It causes several gastrodudenal pathologies such as gastritis, ulcer and gastric adenocarcinoma. The aim of our study was to determine the prevalence of H.pylori infection and to assess the impact of different epidemiological factors as well as principal gastric diseases associ-ated to this infection. We underwent a prospective study during 18 months (month 2016-month 2017) which implicated 201 symptomatic patients for gastric fiboptic endoscopy at the level of Sidi Bel Abbes University hospital. We collected patients’ biopsies to perform a histological study and H. pylori culture. H. pylori identification was carried out based on bacteriological and biochemical analysis. The middle age of our population was (47.29 ±15.97ans) and the sex-ratio =0,8. The global prevalence of Helicobacter pylori infection is of 61.2% (123/201). This rate, after a statistic analysis, seems to be significantly related to age. It is particularly high especially for patients belonging to age range (20-30)-(51-60) years. The gender did not affect the infection prevalence that is more frequent in the gastritis case. We noticed also that HP infection prevalence was important in SBA the hospital. The range age (20-30)-(51-60) years had the highest prevalence of H. pylori and of gastritis which might be a risky ground of gastric cancer appearance. The ulcer pathology maximal rate concerned the group of 51 to 60 years. Above this age, this rate dropped whereas the number of patients suffering from gastric cancer, which presents an important rate in our study, increase for the group of 61-70 years.

scholarly journals Is overwintering mortality driving enigmatic declines? Evaluating the impacts of trematodes and the amphibian chytrid fungus on an anuran from hatching through overwintering

PLoS ONE ◽  
2022 ◽  
Vol 17 (1) ◽  
pp. e0262561
Author(s):  
Olivia Wetsch ◽  
Miranda Strasburg ◽  
Jessica McQuigg ◽  
Michelle D. Boone
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Species Conservation ◽  
Emerging Infectious Diseases ◽  
The Novel ◽  
Chytrid Fungus ◽  
Growth And Survival ◽  
Critical Life Events ◽  
Overwintering Mortality ◽  
Amphibian Chytrid Fungus

Emerging infectious diseases are increasing globally and are an additional challenge to species dealing with native parasites and pathogens. Therefore, understanding the combined effects of infectious agents on hosts is important for species’ conservation and population management. Amphibians are hosts to many parasites and pathogens, including endemic trematode flatworms (e.g., Echinostoma spp.) and the novel pathogenic amphibian chytrid fungus (Batrachochytrium dendrobatidis [Bd]). Our study examined how exposure to trematodes during larval development influenced the consequences of Bd pathogen exposure through critical life events. We found that prior exposure to trematode parasites negatively impacted metamorphosis but did not influence the effect of Bd infection on terrestrial growth and survival. Bd infection alone, however, resulted in significant mortality during overwintering—an annual occurrence for most temperate amphibians. The results of our study indicated overwintering mortality from Bd could provide an explanation for enigmatic declines and highlights the importance of examining the long-term consequences of novel parasite exposure.

scholarly journals Establishement of a national monitoring program based on environmental DNA for amphibians and the chytrid fungus Batrachochytrium dendrobatidis     

2021 ◽  
Vol 4 ◽  
Author(s):  
Omneya Osman ◽  
Johan Andersson ◽  
Tomas Larsson ◽  
Mats Töpel ◽  
Alexander Eiler
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
National Level ◽  
Monitoring Program ◽  
12S Rrna ◽  
Rrna Gene ◽  
Chytrid Fungus ◽  
Rana Arvalis ◽  
Amphibian Species ◽  
National Monitoring ◽  
Wide Range

National monitoring programs provide the basis for evaluating the integrity of ecosystems, their responses to disturbances, and the success of actions taken to conserve or recover biodiversity. In this study, we successfully established a national program for the invasive chytrid fungus Batrachochytrium dendrobatidis (Bd) based on dual TaqMan assays. Amphibian diversity based on metabarcoding of the mitochondrial 12S rRNA gene was also performed. Assays were optimized for sensitive detection of target species from a wide range of amphibian ponds with variable potential of inhibitions for eDNA based detection. An amphibian mock community of 5 species was used to validate the metabarcoding approach while internal standards were used in the case of the dual TaqMan assays. First sampling of over 170 ponds in Norway resulted in Bd detection in 12 environmental samples and one swab sample taken over multiple years indicating the establishment of Bd in Norway. Five amphibian species Bufo bufo, Lissotriton vulgaris, Triturus cristatus, Rana arvalis and Rana temporaria as predicted from data in long-term citizen science reporting systems were widely detected in the collected eDNA samples. Our large scale-monitoring program indicates a low risk of a Bd outbreak and amphibian decline caused by chytridiomycosis but continued monitoring is recommended in the future. These findings indicate that eDNA is an effective method to detect invasive species, and to monitor endangered amphibian species. Still, several shortcomings (such as PCR inhibitors and sample volume) were identified that need to be addressed to improve eDNA-based monitoring at the national level.

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