Cost efficiency in the detection of chytridiomycosis using PCR assay

Kriger, Kerry Matthew; Hero, Jean Marc; Ashton, Kevin J.

doi:10.3354/dao071149

Cited by 122 publications

(119 citation statements)

References 25 publications

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“…BS: breeding starts; BE: breeding ends; Tad: tadpoles; Meta: metamorphs. T1: initiation of breeding; T2: 1 to 2 wk post-breeding; T3: 3 to 4 wk post-breeding; T4: 10 wk post-breeding; na: missing samples this rerun and there were no signs of PCR inhibition, the samples were considered Bd negative, with any previous single positive wells considered the result of inadvertent contamination or background fluorescence (Kriger et al 2006). Following Garner et al (2009), samples were considered PCR-inhibited if IPC cycle thresholds (C T values) were > 2 cycles above IPC C T of the sterile water controls.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of a filtration-based method for detecting Batrachochytrium dendrobatidis in natural bodies of water

Hyman¹,

Collins²

2012

Dis. Aquat. Org.

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Infectious diseases are emerging as a significant threat to wildlife. The resulting increased effort to monitor wildlife diseases is driving the development of innovative pathogen monitoring techniques, including many polymerase chain reaction (PCR)-based diagnostics. Despite the utility of these PCR-based techniques, there is still much to be learned about their ability to accurately detect target pathogens in nature. We assessed the diagnostic sensitivity of a PCR-based water filtration technique to detect the directly transmitted aquatic fungal pathogen Batrachochytrium dendrobatidis (Bd) by comparing the results of 4 repeated filter sampling events from 20 ponds to those of skin swabs from ca. 60 boreal chorus frogs Pseudacris maculata from each pond. Filters failed to detect Bd in 31 to 77% of the swab-positive ponds, depending on the time of sampling. However, after 3 repeated sampling events, filtration of small volumes of water (ca. 600 ml) correctly identified 94% of the ponds that tested Bd positive with swabbing, with the highest rates of detection occurring after breeding but before larvae reached metamorphosis. Our results are a case study demonstrating the importance of timing and resampling for the detection of an aquatic microbial pathogen, Bd, from water. This will be a useful technique for monitoring Bd, but additional data are needed to test the degree to which our findings are species or population specific. Future studies need to examine the sensitivity of this technique in other habitats and species that host Bd. These studies will aid in the development of cost-effective monitoring regimes for Bd and potentially other aquatic pathogens.

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Section: Discussionmentioning

confidence: 99%

Evaluation of a filtration-based method for detecting Batrachochytrium dendrobatidis in natural bodies of water

Hyman¹,

Collins²

2012

Dis. Aquat. Org.

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“…Swabs were air-dried in the field and stored individually in labeled microcentrifuge tubes before PCR analysis. We used standard Bd DNA extraction and real-time PCR methods (23,24), except that swab extracts were analyzed singly instead of in triplicate (42). We defined infection intensity as the number of "zoospore equivalents" per swab.…”

Section: Methodsmentioning

confidence: 99%

Dynamics of an emerging disease drive large-scale amphibian population extinctions

Vredenburg

Knapp²,

Tunstall

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

545

650

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Epidemiological theory generally suggests that pathogens will not cause host extinctions because the pathogen should fade out when the host population is driven below some threshold density. An emerging infectious disease, chytridiomycosis, caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd) is directly linked to the recent extinction or serious decline of hundreds of amphibian species. Despite continued spread of this pathogen into uninfected areas, the dynamics of the host-pathogen interaction remain unknown. We use fine-scale spatiotemporal data to describe (i) the invasion and spread of Bd through three lake basins, each containing multiple populations of the mountain yellow-legged frog, and (ii) the accompanying host-pathogen dynamics. Despite intensive sampling, Bd was not detected on frogs in study basins until just before epidemics began. Following Bd arrival in a basin, the disease spread to neighboring populations at ≈700 m/yr in a wave-like pattern until all populations were infected. Within a population, infection prevalence rapidly reached 100% and infection intensity on individual frogs increased in parallel. Frog mass mortality began only when infection intensity reached a critical threshold and repeatedly led to extinction of populations. Our results indicate that the high growth rate and virulence of Bd allow the nearsimultaneous infection and buildup of high infection intensities in all host individuals; subsequent host population crashes therefore occur before Bd is limited by density-dependent factors. Preventing infection intensities in host populations from reaching this threshold could provide an effective strategy to avoid the extinction of susceptible amphibian species in the wild.amphibian declines | Batrachochytrium dendrobatidis | chytridiomycosis | emerging infectious disease | Rana muscosa E arth's biodiversity is increasingly threatened with extinction.

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“…We quantified the samples at the W.M. Keck Center on the University of Illinois campus using a Taqman ABI 7900 real time PCR machine (Applied Biosystems, Foster City, California, USA) and the qPCR methods detailed by Boyle et al (2004) with the modifications described by Kriger et al (2006) and Ruthig and DeRidder (2012). Samples were run on 364-well plates and used 10-lL reaction volumes.…”

Section: Laboratory Methodsmentioning

confidence: 99%

Canopy cover and drought influence the landscape epidemiology of an amphibian chytrid fungus

2015

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Abstract. Batrachochytrium dendrobatidis (Bd) is a globally distributed fungal pathogen of amphibians that has caused amphibian population declines. Prevalence and infection intensity of Bd should vary spatially across heterogeneous landscapes because survival of the pathogen depends on environmental conditions including humidity and temperature. Wetland temperatures should vary with forest canopy cover, but few studies have examined the relationship between Bd prevalence and canopy cover. We sampled anurans for Bd at 33 wetlands in Illinois across a canopy cover gradient during the severe drought of 2012 and during more typical weather in 2013. We hypothesized that anurans from closed canopy wetlands would have higher Bd prevalence than anurans from open canopy wetlands because high canopy cover would prevent temperatures from exceeding Bd's critical maximum temperature as often. We used occupancy modeling to examine how Bd prevalence varied spatially in relation to environmental covariates, and to determine if weather conditions altered such relationships. We analyzed all common species combined and Spring Peepers (Pseudacris crucifer) separately. Bd was widespread among the study wetlands. During the drought year of 2012, however, Bd prevalence and infection intensity were substantially reduced. Although wetland temperatures were related negatively to canopy cover, the influence of canopy cover on Bd was complex. Bd prevalence for Spring Peepers was related positively to canopy cover during the drought, but not in the non-drought year. Bd prevalence for all common species was not related positively to canopy cover in either year. Effects of other environmental covariates, such as water depth, also differed between years. Weather conditions had a large impact on Bd infection patterns, which makes predicting pathogen dynamics difficult. In the Midwest region of the United States, climate change models predict more frequent droughts, which may generally inhibit Bd while also altering the effect of environmental factors such as canopy cover on Bd prevalence for amphibians.

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Cost efficiency in the detection of chytridiomycosis using PCR assay

Cited by 122 publications

References 25 publications

Evaluation of a filtration-based method for detecting Batrachochytrium dendrobatidis in natural bodies of water

Evaluation of a filtration-based method for detecting Batrachochytrium dendrobatidis in natural bodies of water

Dynamics of an emerging disease drive large-scale amphibian population extinctions

Canopy cover and drought influence the landscape epidemiology of an amphibian chytrid fungus

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