scholarly journals Reservoir frogs: seasonality of Batrachochytrium dendrobatidis infection in robber frogs in Dominica and Montserrat

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7021 ◽  
Author(s):  
Michael A. Hudson ◽  
Richard A. Griffiths ◽  
Lloyd Martin ◽  
Calvin Fenton ◽  
Sarah-Louise Adams ◽  
...  
Keyword(s):  
Wildlife Conservation ◽  
Batrachochytrium Dendrobatidis ◽  
Seasonal Pattern ◽  
Emerging Infectious Diseases ◽  
Seasonal Patterns ◽  
Infection Prevalence ◽  
Reservoir Species ◽  
Reintroduction Success ◽  
Species Declines

Emerging infectious diseases are an increasingly important threat to wildlife conservation, with amphibian chytridiomycosis, caused by Batrachochytrium dendrobatidis, the disease most commonly associated with species declines and extinctions. However, some amphibians can be infected with B. dendrobatidis in the absence of disease and can act as reservoirs of the pathogen. We surveyed robber frogs (Eleutherodactylus spp.), potential B. dendrobatidis reservoir species, at three sites on Montserrat, 2011–2013, and on Dominica in 2014, to identify seasonal patterns in B. dendrobatidis infection prevalence and load (B. dendrobatidis genomic equivalents). On Montserrat there was significant seasonality in B. dendrobatidis prevalence and B. dendrobatidis load, both of which were correlated with temperature but not rainfall. B. dendrobatidis prevalence reached 35% in the cooler, drier months but was repeatedly undetectable during the warmer, wetter months. Also, B. dendrobatidis prevalence significantly decreased from 53.2% when the pathogen emerged on Montserrat in 2009 to a maximum 34.8% by 2011, after which it remained stable. On Dominica, where B. dendrobatidis emerged seven years prior to Montserrat, the same seasonal pattern was recorded but at lower prevalence, possibly indicating long-term decline. Understanding the dynamics of disease threats such as chytridiomycosis is key to planning conservation measures. For example, reintroductions of chytridiomycosis-threatened species could be timed to coincide with periods of low B. dendrobatidis infection risk, increasing potential for reintroduction success.

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 Prevalence of the fungal pathogen Batrachochytrium dendrobatidis in amphibians of Costa Rica predated first-known epizootic

2018 ◽  
Author(s):  
Marina E. De León ◽  
Héctor Zumbado-Ulate ◽  
Adrián García-Rodríguez ◽  
Gilbert Alvarado ◽  
Hasan Sulaeman ◽  
...  
Keyword(s):  
Costa Rica ◽  
Fungal Pathogen ◽  
Batrachochytrium Dendrobatidis ◽  
Emerging Infectious Diseases ◽  
Infection Prevalence ◽  
Pcr Assay ◽  
Local Data ◽  
Amphibian Species ◽  
Genetic Lineages ◽  
Quantitative Pcr Assay

AbstractEmerging infectious diseases are a growing threat to biodiversity worldwide. Outbreaks of the infectious disease chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), have caused the decline and extinction of numerous amphibian species. In Costa Rica, a major decline event occurred in 1987, more than two decades before this pathogen was discovered. The loss of many species in Costa Rica is assumed to be due to Bd-epizootics, but there are few studies that provide data from amphibians in the time leading up to the proposed epizootics. In this study, we provide new data on Bd infection rates of amphibians collected throughout Costa Rica, in the decades prior to the epizootics. We used a quantitative PCR assay to test for Bd infection in 1016 specimens collected throughout Costa Rica. We found Bd-infected hosts collected as early as 1964, and a infection prevalence average per decade of just 4%. The infection prevalence remained relatively low and geographically constrained until the 1980s when epizootics are hypothesized to have occurred. After that time, infection prevalence increased three-fold and Bd-infected hosts we collected throughout the entire country. Our results, suggest that Bd may either have invaded Costa Rica earlier than previously known, and spread more slowly than previously reported, or that an endemic lineage of the pathogen may exists. To help visualize areas where future studies should take place, we provide a Bd habitat suitability model trained with local data. Studies that provide information on genetic lineages of Bd are needed to determine whether an endemic lineage of Bd or the Global Panzootic Lineage (identified from mass die off sites globally) was present in Costa Rica and responsible for the epizootics that caused amphibian communities to collapse.

Seasonal prevalence of the amphibian chytrid in a tropical pond-dwelling tadpole species

2020 ◽  
Vol 142 ◽  
pp. 171-176
Author(s):  
J Ruggeri ◽  
AGS Martins ◽  
AHR Domingos ◽  
I Santos ◽  
IB Viroomal ◽  
...  
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Seasonal Pattern ◽  
Decomposition Analysis ◽  
Amphibian Conservation ◽  
Infection Prevalence ◽  
Local Climate ◽  
Relevant Role ◽  
Potential Reservoir ◽  
Imminent Threat ◽  
Reservoir Hosts

Infection by the chytrid fungus Batrachochytrium dendrobatidis (Bd) is a major threat to amphibians and has caused catastrophic global declines of amphibian populations. Some studies have detected a seasonal pattern of infection associated with the local climate, and although most of them have focused on investigating the seasonality of Bd in relation to its impacts on amphibians, fewer have aimed to understand the chytrid persistence in the amphibian assemblage over seasons by investigating reservoir hosts. Since tadpoles are generally tolerant to Bd infection, they often play a relevant role in local disease dynamics. Thus, we hypothesized that tadpoles of Boana faber, a species that can be found in permanent ponds throughout the seasons, would function as Bd reservoirs. We therefore investigated Bd infection prevalence in tadpoles of this species over 2 yr in a nature reserve. As expected, we detected a seasonal variation of Bd infection, with a higher prevalence of Bd during the coldest months (winter) when compared to the warmer months (summer). Interestingly, our seasonal-trend decomposition analysis showed that Bd prevalence is increasing annually in the area, which could represent either a natural fluctuation of this pathogen, or an imminent threat to that anuran assemblage. With this study, we highlight the tadpole of B. faber as a potential reservoir for Bd, and we suggest that monitoring Bd in such hosts could be a powerful tool for identifying priority areas for amphibian conservation.

scholarly journals Fighting fungi with fungi: the mycobiome contribution to emerging disease in amphibians

2017 ◽  
Author(s):  
Patrick Kearns ◽  
Sarah Fischer ◽  
Saioa Fernández-Beaskoetxea ◽  
Caitlin Gabor ◽  
Jaime Bosch ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
High Throughput Sequencing ◽  
Batrachochytrium Dendrobatidis ◽  
Emerging Infectious Diseases ◽  
Pathogen Defense ◽  
Colonization Potential ◽  
Additional Resistance ◽  
Symbiotic Fungi

Emerging infectious diseases caused by fungal taxa are increasing and are placing a substantial burden on economies and ecosystems worldwide. Of the emerging fungal diseases, chytridomycosis caused by the fungus Batrachochytrium dendrobatidis (hereafter Bd) is causing a global amphibian extinction. The host frog does have come internal innate immunity, as well as additional resistance through cutaneous microbial communities, leading to the development of probiotic bacterial therapies with mixed results. Unknown is the role of fungi in the protection against Bd infection, and as such, we examined the overlapping roles of bacterial and fungal microbiota in pathogen defense with a combination of high-throughput sequencing and culturing of symbiotic fungi from poison arrow frogs (Dendrobates sp.). Our analyses revealed that abundance of cutaneous fungi contributed more to pathogen defense (~45%), than bacteria (~10%) and these differed from environmental microbiota. Further, we demonstrated that a fungal probiotic therapy did not induce an endocrine-immune reaction in contrast to bacterial probiotics that stressed amphibian hosts and suppressed antimicrobial peptide responses, limiting their long-term colonization potential. Our results suggest that probiotic strategies against amphibian fungal pathogens should refocus on host-associated and environmental fungi such as Penicillium and member of the families Chaetomiaceae and Lasiosphaeriaceae.

scholarly journals Fighting fungi with fungi: the mycobiome contribution to emerging disease in amphibians

2017 ◽  
Author(s):  
Patrick Kearns ◽  
Sarah Fischer ◽  
Saioa Fernández-Beaskoetxea ◽  
Caitlin Gabor ◽  
Jaime Bosch ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
High Throughput Sequencing ◽  
Batrachochytrium Dendrobatidis ◽  
Emerging Infectious Diseases ◽  
Pathogen Defense ◽  
Colonization Potential ◽  
Additional Resistance ◽  
Symbiotic Fungi

Emerging infectious diseases caused by fungal taxa are increasing and are placing a substantial burden on economies and ecosystems worldwide. Of the emerging fungal diseases, chytridomycosis caused by the fungus Batrachochytrium dendrobatidis (hereafter Bd) is causing a global amphibian extinction. The host frog does have come internal innate immunity, as well as additional resistance through cutaneous microbial communities, leading to the development of probiotic bacterial therapies with mixed results. Unknown is the role of fungi in the protection against Bd infection, and as such, we examined the overlapping roles of bacterial and fungal microbiota in pathogen defense with a combination of high-throughput sequencing and culturing of symbiotic fungi from poison arrow frogs (Dendrobates sp.). Our analyses revealed that abundance of cutaneous fungi contributed more to pathogen defense (~45%), than bacteria (~10%) and these differed from environmental microbiota. Further, we demonstrated that a fungal probiotic therapy did not induce an endocrine-immune reaction in contrast to bacterial probiotics that stressed amphibian hosts and suppressed antimicrobial peptide responses, limiting their long-term colonization potential. Our results suggest that probiotic strategies against amphibian fungal pathogens should refocus on host-associated and environmental fungi such as Penicillium and member of the families Chaetomiaceae and Lasiosphaeriaceae.

Seasonal Variation of Suicide in the City of São Paulo, Brazil, 1996–2010

Crisis ◽  
2014 ◽  
Vol 35 (1) ◽  
pp. 5-9 ◽  
Author(s):  
Daniel Hideki Bando ◽  
Fernando Madalena Volpe
Keyword(s):  
Seasonal Pattern ◽  
Total Sample ◽  
Sao Paulo ◽  
Seasonal Patterns ◽  
São Paulo ◽  
Health Statistics ◽  
Males And Females ◽  
June July ◽  
The City ◽  
Over Time

Background: In light of the few reports from intertropical latitudes and their conflicting results, we aimed to replicate and update the investigation of seasonal patterns of suicide occurrences in the city of São Paulo, Brazil. Methods: Data relating to male and female suicides were extracted from the Mortality Information Enhancement Program (PRO-AIM), the official health statistics of the municipality of São Paulo. Seasonality was assessed by studying distribution of suicides over time using cosinor analyses. Results: There were 6,916 registered suicides (76.7% men), with an average of 39.0 ± 7.0 observed suicides per month. For the total sample and for both sexes, cosinor analysis estimated a significant seasonal pattern. For the total sample and for males suicide peaked in November (late spring) with a trough in May–June (late autumn). For females, the estimated peak occurred in January, and the trough in June–July. Conclusions: A seasonal pattern of suicides was found for both males and females, peaking in spring/summer and dipping in fall/winter. The scarcity of reports from intertropical latitudes warrants promoting more studies in this area.

scholarly journals Pseudogymnoascus destructans growth in wood, soil and guano substrates

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jenny Urbina ◽  
Tara Chestnut ◽  
Jennifer M. Allen ◽  
Taal Levi
Keyword(s):  
Dna Extraction ◽  
Emerging Infectious Diseases ◽  
Transmission Risk ◽  
Pseudogymnoascus Destructans ◽  
White Nose Syndrome ◽  
Management Interventions ◽  
Pathogen Persistence ◽  
Tenfold Increase ◽  
And Control

AbstractUnderstanding how a pathogen can grow on different substrates and how this growth impacts its dispersal are critical to understanding the risks and control of emerging infectious diseases. Pseudogymnoascus destructans (Pd) causes white-nose syndrome (WNS) in many bat species and can persist in, and transmit from, the environment. We experimentally evaluated Pd growth on common substrates to better understand mechanisms of pathogen persistence, transmission and viability. We inoculated autoclaved guano, fresh guano, soil, and wood with live Pd fungus and evaluated (1) whether Pd grows or persists on each (2) if spores of the fungus remain viable 4 months after inoculation on each substrate, and (3) whether detection and quantitation of Pd on swabs is sensitive to the choice to two commonly used DNA extraction kits. After inoculating each substrate with 460,000 Pd spores, we collected ~ 0.20 g of guano and soil, and swabs from wood every 16 days for 64 days to quantify pathogen load through time using real-time qPCR. We detected Pd on all substrates over the course of the experiment. We observed a tenfold increase in pathogen loads on autoclaved guano and persistence but not growth in fresh guano. Pathogen loads increased marginally on wood but declined ~ 60-fold in soil. After four months, apparently viable spores were harvested from all substrates but germination did not occur from fresh guano. We additionally found that detection and quantitation of Pd from swabs of wood surfaces is sensitive to the DNA extraction method. The commonly used PrepMan Ultra Reagent protocol yielded substantially less DNA than did the QIAGEN DNeasy Blood and Tissue Kit. Notably the PrepMan Ultra Reagent failed to detect Pd in many wood swabs that were detected by QIAGEN and were subsequently found to contain substantial live conidia. Our results indicate that Pd can persist or even grow on common environmental substrates with results dependent on whether microbial competitors have been eliminated. Although we observed clear rapid declines in Pd on soil, viable spores were harvested four months after inoculation. These results suggest that environmental substrates and guano can in general serve as infectious environmental reservoirs due to long-term persistence, and even growth, of live Pd. This should inform management interventions to sanitize or modify structures to reduce transmission risk as well early detection rapid response (EDRR) planning.

Long-term monitoring of molecular markers can distinguish different seasonal patterns of fecal indicating bacteria sources

2015 ◽  
Vol 71 ◽  
pp. 227-243 ◽  
Author(s):  
Timothy E. Riedel ◽  
Vanessa Thulsiraj ◽  
Amity G. Zimmer-Faust ◽  
Rosi Dagit ◽  
Jenna Krug ◽  
...  
Keyword(s):  
Molecular Markers ◽  
Seasonal Patterns ◽  
Long Term Monitoring ◽  
Term Monitoring

scholarly journals Seasonal pattern of hepatitis E virus prevalence in swine in two different geographical areas of China

2013 ◽  
Vol 141 (11) ◽  
pp. 2403-2409 ◽  
Author(s):  
Y. H. LU ◽  
H. Z. QIAN ◽  
A. Q. HU ◽  
X. QIN ◽  
Q. W. JIANG ◽  
...  
Keyword(s):  
Hepatitis E Virus ◽  
Seasonal Pattern ◽  
Eastern China ◽  
Geographical Area ◽  
Hepatitis E ◽  
Southwestern China ◽  
Seasonal Patterns ◽  
Virus Prevalence ◽  
Swine Hepatitis ◽  
A Minor

SUMMARYWe studied seasonal patterns of swine hepatitis E virus (HEV) infection in China. From 2008 to 2011, 4200 swine bile specimens were collected for the detection of HEV RNA. A total of 92/2400 (3·83%) specimens in eastern China and 47/1800 (2·61%) specimens in southwestern China were positive for HEV. Seasonal patterns differing by geographical area were suggested. In eastern China, the major peak of HEV RNA prevalence was during March–April, with a minor peak during September–October, and a dip during July–August. In southwestern China, the peak was during September–October and the dip during March–April. The majority of subtype 4a cases (63/82, 76·83%) were detected in the first half of the year, while the majority of subtype 4b cases (26/29, 89·66%) were concentrated in the second half of the year, suggesting that different subtypes contribute to different peaks. Our results indicate that the distribution of HEV subtypes is associated with seasonal patterns.

Seasonal variation in births in rural East Pakistan

1972 ◽  
Vol 4 (1) ◽  
pp. 107-116 ◽  
Author(s):  
John Stoeckel ◽  
A. K. M. Alauddin Choudhury
Keyword(s):  
Seasonal Variation ◽  
Social Factors ◽  
Seasonal Pattern ◽  
Seasonal Patterns ◽  
First Order ◽  
Monthly Temperature ◽  
Monthly Distribution ◽  
Number Of Births

SummaryAn analysis of the monthly distribution of births in two areas of Matlab Thana, East Pakistan, indicates that there is a seasonal variation in births different from what would be expected by chance. The highest proportion of births occur in the last three months of a year and the lowest proportion between May and July. Investigation into some of the environmental and social factors which might contribute to the seasonal pattern revealed the following: mean minimum monthly temperature 9 months before birth was inversely related to the number of births; all occupations had seasonal patterns different from what would be expected by chance and the business and mill-and-office occupations had distributions significantly different from each other; the distribution of births for all pregnancy orders was different from chance and the distribution for first order pregnancies was significantly different from those for third and fourth or higher orders.

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