Assessing host response to disease treatment: how chytrid-susceptible frogs react to increased water salinity

2017 ◽  
Vol 44 (8) ◽  
pp. 648 ◽  
Author(s):  
Kaya L. Klop-Toker ◽  
Jose W. Valdez ◽  
Michelle P. Stockwell ◽  
Matthew E. Edgar ◽  
Loren Fardell ◽  
...  
Keyword(s):  
Field Study ◽  
Environmental Variables ◽  
Batrachochytrium Dendrobatidis ◽  
Saline Water ◽  
Water Level Fluctuations ◽  
Habitat Manipulation ◽  
Susceptible Host ◽  
Growth And Survival ◽  
Litoria Aurea ◽  
Host Behaviour

Context The severity and prevalence of the amphibian fungal pathogen, Batrachochytrium dendrobatidis (Bd) is correlated with several environmental variables, including salinity, temperature, and moisture content, which influence the pathogen’s growth and survival. Habitats that contain these environmental variables at levels outside of those optimal for Bd growth and survival may facilitate the survival of susceptible host species. Therefore, manipulation of environmental salinity is a potential management strategy to help conserve Bd-susceptible species. However, host behaviour also influences disease dynamics, and the success of habitat manipulation programs depends on how hosts use this altered habitat. Aims To assess if the Bd-susceptible green and golden bell frog, Litoria aurea, will select waterbodies with a salinity increased to S=3; if this selection is affected by infection; and if a frog’s time in a waterbody of this salinity affects infection load or blood physiology. Methods We conducted a filmed choice experiment and a 3-year field study where infected and uninfected frogs could choose between fresh or saline waterbodies. Key results In both the laboratory experiment and field study, Bd-infected L. aurea spent a significantly greater amount of time in or closer to a waterbody than uninfected frogs. Experimentally infected frogs tended to prefer the saline water over fresh, but their choice of water usage did not differ statistically from uninfected frogs. In the field, frogs began to avoid ponds when salinities rose above S=5. Conclusions Because both wild and captive, and infected and uninfected L. aurea readily selected waterbodies with a salinity of S=3, this salinity could potentially be used as a passive method for reducing the severity of Bd when managing this species. However, further testing is needed to understand the efficacy of this treatment, and care must be taken to prevent salinities rising above S=5, because this level seems to produce an avoidance response and therefore may not be suitable in every location. Implications Manipulation of aquatic habitats may be a worthwhile focus for Bd management in habitats where water level fluctuations are minimal.

Effects of Saline Water on Growth and Survival of Mottled Duck Ducklings in Louisiana

1991 ◽  
Vol 55 (3) ◽  
pp. 471 ◽  
Author(s):  
Anne M. Moorman ◽  
Thomas E. Moorman ◽  
Guy A. Baldassarre ◽  
David M. Richard
Keyword(s):  
Saline Water ◽  
Growth And Survival ◽  
Mottled Duck

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 In-situ severe breeding habitat intervention only achieves temporary success in reducing Batrachochytrium dendrobatidis infection

2020 ◽  
Vol 41 (2) ◽  
pp. 261-267 ◽  
Author(s):  
Andrés Fernández-Loras ◽  
Luz Boyero ◽  
Jaime Bosch
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Research Effort ◽  
Breeding Habitat ◽  
Habitat Manipulation ◽  
Breeding Sites ◽  
Breeding Habitats ◽  
The Common ◽  
Natural Breeding ◽  
Midwife Toad

Abstract Chytridiomycosis, an emerging infectious disease caused by the fungus Batrachochytrium dendrobatidis (Bd), is causing sharp declines in amphibian populations around the globe. A substantial research effort has been made to study the disease, including treatments against Bd, but most treatments have been applied to captive amphibians only. We report a study aimed at clearing wild populations of the Common Midwife toad Alytes obstetricans. We removed all larvae from natural breeding sites (cattle troughs) and conducted two types of severe breeding habitat manipulation (complete drying and fencing for the whole breeding season). While larval removal followed by drying was a successful method of Bd elimination, the effect was only temporary. Since terrestrial habits of adult A. obstetricans prevent them from infection, our findings suggest that, even in simple breeding habitats where all aquatic amphibian stages can be handled and extreme habitat intervention is possible, Bd cannot be eliminated without controlling other potential Bd reservoirs in the surroundings of breeding sites.

scholarly journals Environmental factors determining growth of salamander larvae: A field study

2015 ◽  
Vol 61 (3) ◽  
pp. 421-427 ◽  
Author(s):  
Laura Limongi ◽  
Gentile Francesco Ficetola ◽  
Giuseppe Romeo ◽  
Raoul Manenti
Keyword(s):  
Field Study ◽  
Environmental Variables ◽  
Larval Growth ◽  
Experimental Studies ◽  
Field Studies ◽  
Development Rate ◽  
Biotic Factors ◽  
Natural Conditions ◽  
Fire Salamander ◽  
Salamander Larvae

Abstract Larval growth and survival of organisms are strongly influenced by abiotic and biotic factors, as demonstrated by experimental studies performed under controlled laboratory or semi-natural conditions. Even if they have many advantages, experiments cannot cover the full complexity of natural conditions and field studies are needed for a better understanding of how environmental variation determines growth and development rate. Fire salamander Salamandra salamandra females give birth to larvae in a variety of habitats, both epigean and subterranean. In caves, salamander larvae successfully grow and metamorphose, but their growth is more than three times longer than in epigean streams and factors determining these differences require investigation. We performed a field study to understand the factors related to the growth of fire salamander larvae in different environmental conditions, evaluating the relationship between environmental features and larval growth and differences between caves and epigean spring habitats. Both caves and epigean larvae successfully grew. Capture-mark-recapture allowed to individually track individuals along their whole development, and measure their performance. Growth rate was significantly affected by environmental variables: larvae grew faster in environments with abundant invertebrates and few conspecifics. Taking into account the effect of environmental variables, larval growth was significantly lower in caves. Food availability plays a different effect in the two environments. Larval growth was positively related to the availability of invertebrates in epigean sites only. The development rate of hypogeous populations of salamanders is slower because of multiple parameters, but biotic factors play a much stronger role than the abiotic ones.

Effects of the trematode Microphallus turgidus on locomotion and prey capture in the grass shrimp Palaemonetes pugio

2003 ◽  
Vol 77 (4) ◽  
pp. 327-330 ◽  
Author(s):  
R.N. Khan ◽  
J.A. Spiers ◽  
O.J. Pung
Keyword(s):  
Intermediate Host ◽  
East Coast ◽  
Prey Capture ◽  
Grass Shrimp ◽  
Palaemonetes Pugio ◽  
Growth And Survival ◽  
Data Support ◽  
The Usa ◽  
Host Behaviour ◽  
Capture Rates

AbstractThe grass shrimp, Palaemonetes pugio, is common in estuaries and marshes along the east coast of the USA and is frequently infected with metacercariae of the trematode, Microphallus turgidus. To test whether or not M. turgidus has an effect on intermediate host behaviour, the length of time spent swimming and walking over 1 min and 3 min intervals and prey (Artemia) capture rates of uninfected grass shrimp and those infected with 1–10, 11–20 or 21–30 metacercarial cysts were compared. Uninfected shrimps spent significantly more time swimming than infected shrimps during the first minute of observation. There were no differences between the control and infected groups in terms of swimming at 3 min, walking at 1 and 3 min, or in numbers of prey captured. These results indicate that M. turgidus may induce little or no change in grass shrimp locomotion nor in prey capture behaviour. This is in contrast to other parasites that modify intermediate host behaviour to enhance their transmission to definitive hosts. Furthermore, these data support earlier studies indicating that M. turgidus does not affect the growth and survival of P. pugio.

Impact of temperature and nutrient dynamics on growth and survival of Corbicula fluminea : A field study in oligotrophic Lake Constance

2017 ◽  
Vol 102 (1-2) ◽  
pp. 15-28 ◽  
Author(s):  
Timo Basen ◽  
Katja M. Fleckenstein ◽  
Karsten Rinke ◽  
Karl-Otto Rothhaupt ◽  
Dominik Martin-Creuzburg
Keyword(s):  
Field Study ◽  
Nutrient Dynamics ◽  
Corbicula Fluminea ◽  
Oligotrophic Lake ◽  
Lake Constance ◽  
Growth And Survival

scholarly journals Cryptic disease-induced mortality may cause host extinction in an apparently stable host–parasite system

2017 ◽  
Vol 284 (1863) ◽  
pp. 20171176 ◽  
Author(s):  
Andrés Valenzuela-Sánchez ◽  
Benedikt R. Schmidt ◽  
David E. Uribe-Rivera ◽  
Francisco Costas ◽  
Andrew A. Cunningham ◽  
...  
Keyword(s):  
Batrachochytrium Dendrobatidis ◽  
Population Decline ◽  
Parasitic Infection ◽  
Parasite Prevalence ◽  
Host Population ◽  
Population Declines ◽  
Epidemic Disease ◽  
Susceptible Host ◽  
Conservation Practice ◽  
Host Parasite

The decline of wildlife populations due to emerging infectious disease often shows a common pattern: the parasite invades a naive host population, producing epidemic disease and a population decline, sometimes with extirpation. Some susceptible host populations can survive the epidemic phase and persist with endemic parasitic infection. Understanding host–parasite dynamics leading to persistence of the system is imperative to adequately inform conservation practice. Here we combine field data, statistical and mathematical modelling to explore the dynamics of the apparently stable Rhinoderma darwinii – Batrachochytrium dendrobatidis (Bd) system. Our results indicate that Bd-induced population extirpation may occur even in the absence of epidemics and where parasite prevalence is relatively low. These empirical findings are consistent with previous theoretical predictions showing that highly pathogenic parasites are able to regulate host populations even at extremely low prevalence, highlighting that disease threats should be investigated as a cause of population declines even in the absence of an overt increase in mortality.

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