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Amphibian larvae can affect the structure and functioning of freshwater ecosystems, but their effects have been little explored although amphibian biodiversity is rapidly declining. Given that larvae of different amphibian species belong to different trophic levels, their effects on freshwater communities and processes can be expected to differ, with herbivores likely having direct effects on algae and predators having indirect effects through trophic cascades. We explored this question through a mesocosm experiment conducted in montane ponds, using an anuran and a urodele species affected by emergent diseases. We used different scenarios of reduction and loss of one or both species, and compared them to a control scenario representing a typical amphibian community in the study area composed of four species, with total larval density held constant. Loss of the anuran resulted in lower chlorophyll concentration and algal density, likely due to replacement by more efficient grazers. Loss of the urodele produced similar trends but weaker, possibly due to an increase of invertebrate grazing activity in the absence of this predator. Our study shows how the loss of amphibian species can alter the structure of montane ponds, but also how the mechanisms involved and the intensity of effects differ for different species. [ABSTRACT FROM AUTHOR]

Since the confirmation of African swine fever (ASF) in South Korea in 2019, its spread, predominantly in wild boars, has been a significant concern. A key factor in this situation is the lack of identification of risk factors by surveillance bias. The unique orography, characterized by high mountains, complicates search efforts, leading to overlooked or delayed case detection and posing risks to the swine industry. Additionally, shared rivers with neighboring country present a continual threat of virus entry. This study employs geospatial analysis and statistical methods to 1) identify areas at high risk of ASF occurrence but possibly under-surveilled, and 2) indicate strategic surveillance points for monitoring the risk of ASF virus entry through water bodies and basin influences. Pearson's rho test indicated that elevation (rho = -0.908, p-value < 0.001) and distance from roads (rho = -0.979, p-value < 0.001) may have a significant impact on limiting surveillance activities. A map of potential under-surveilled areas was created considering these results and was validated by a chi-square goodness-of-fit test (X-square = 208.03, df = 1, p-value < 0.001). The strong negative correlation (rho = -0.997, p-value <0.001) between ASF-positive wild boars and distance from water sources emphasizes that areas surrounding rivers are one of the priority areas for monitoring. The subsequent hydrological analyses provided important points for monitoring the risk of virus entry via water from the neighboring country. This research aims to facilitate early detection and prevent further spread of ASF. [ABSTRACT FROM AUTHOR]

Simple Summary: Amphibians are the most threatened vertebrate class on Earth, and assisted reproductive technologies are essential tools to complement other conservation efforts. We established initial assisted reproductive technologies for Alytes obstetricans, a terrestrial breeding anuran whose males carry the egg strings twined around their hind limbs until hatching. Non-lethal gamete collection by injection of hormones was performed and allowed the collection of hormonally-induced sperm and eggs. However, poor response to hormonal stimulation of spermiation was obtained (range 17 to 50% of treated males). These gametes were combined and fertilization took place and completed embryo development in 10% of eggs. In addition, two methods for captive-rearing of embryos were tested: keeping the eggs together (mimicking natural arrangement) or splitting the eggs (to reduce fungal propagation) on moist paper. When eggs were separated, all clutches exhibited embryo survival (ranging from 27 to 61%) while only 8% of clutches presented embryo survival when eggs were kept together. This method for captive-rearing of eggs could be implemented in captive breeding programs for different species of Alytes. Although successful, sperm collection and artificial fertilization should be optimized to contribute to the management of wild and captive populations of this and related species. The genus Alytes consists of six primitive terrestrial-breeding species (five of them endangered or present in restricted distributions) with unique male parental care. Alytes obstetricans was used as a model for the development of assisted reproductive technologies for gamete collection, artificial fertilization and captive-rearing of embryos. Sperm collection was achieved with human chorionic gonadotropin (hCG), but only 17 to 50% of males responded to the hormone. In addition, an effect of captivity on sperm quality was observed. A combination of gonadotropin-releasing hormone agonist (GnRHa) and hCG was tested for induction of ovulation, and 100% of females responded to the treatment. Recently collected sperm was used in artificial fertilization, and 10% of eggs showed complete embryo development. To design a method for captive-rearing of embryos, natural clutches (n = 13) were removed from males and divided into two sub-clutches. One was kept with all eggs together and in the other, the egg string was cut and eggs were split individually. All sub-clutches with eggs kept separated presented embryo survival (ranging from 27 to 61%) that hatched normally, while only one sub-clutch with embryos maintained together had some embryo survival (36%). These results may contribute to the management of this and related species. [ABSTRACT FROM AUTHOR]

We describe the call of Barbourula busuangensis, a peculiar and elusive fully aquatic frog endemic to the Palawan archipelago of western Philippines. This species is so poorly known that most of its basic natural history characteristics (reproductive mode and seasonality, diet, age structure, lifespan) remain to be discovered. Contrary to the calls of other frog species adapted to life in fast-flowing streams, the call of B. busuangensis has a very low fundamental frequency around 250 Hz, with an average duration of 1.2 seconds. Additionally, its pulsed, amplitude modulated structure differs from the tonal calls of all known species in its most closely-related (sister) clade, the genus Bombina. [ABSTRACT FROM AUTHOR]

Chytridiomycosis is affecting hundreds of amphibian species worldwide, but while in tropical areas, adult individuals have been the focus of most investigations, the exact role played by infection intensity of breeding adults is not well understood in temperate areas. We conducted mark–recapture–capture surveys during spiny common toad breeding seasons from 2006 to 2018 at the site of the first recorded outbreak of chytridiomycosis in Europe, the Peñalara Massif (Sierra de Guadarrama National Park, central Spain), and collected infection samples and several variables related to the reproductive effort of male individuals. We used general linear mixed models to evaluate the contribution of study variables on the infection loads of adult male toads exhibited at their capturing date. We also analysed the differences on several male characteristics between the pond with the largest breeding population against the rest of the ponds. We found that the duration of time spent in the waterbody and the condition of the host predicted infection loads. Animals of good physical condition, that spent longer in water, have higher infection levels than individuals with the opposite set of traits. The pond supporting the largest breeding population housed smaller male toads and in poorer condition. Our results are consistent with a shift in reproductive strategy in response to infection and potentially a strategy of tolerance, rather than resistance to infection. These findings have applications for disease mitigation and theoretical implications related to the trade-offs made and the evolution of traits in response to the disease. [ABSTRACT FROM AUTHOR]

In September 2018, classical swine fever (CSF) reemerged in Japan after more than a quarter of a century. After the first notification on a pig farm, wild boars positive for CSF were found continuously in the surrounding area. Gifu was the first prefecture in Japan to disseminate oral vaccines to wild boars in March 2019, with vaccines spread to approximately 14,000 sites between 2019 and 2020. While these diligent measures seemed to have shown some effectiveness, several vaccine spray sites remained without wild boar emergence. Based on the vaccine dissemination records from these periods, this study conducted a statistical analysis to propose more effective vaccine dissemination sites. First, a generalized linear mixed model was used to identify factors correlated with wild boar emergence. Then, two spatial interpolation methods, inverse distance weighted (IDW) and Kriging, were adopted to create a probability map of wild boar emergence for the entire Gifu Prefecture. The analysis showed a positive correlation between wild boar emergence and the appearance of raccoons, raccoon dogs, and crows as well as road density and wild boar distribution index. In particular, raccoon (OR: 1.83, 95%CI: 1.25–2.68, p < 0.001), raccoon dog (OR: 1.81, 95%CI: 1.25–2.66, p < 0.001), and medium level road density (OR: 1.56, 95%CI: 1.04–2.39, p = 0.04) were strongly correlated with wild boar emergence. The spatial interpolation approach resulted in better prediction accuracy for the Kriging method than for IDW by the root mean square error, but both approaches identified a high wild boar appearance probability area in southeastern Gifu and a low appearance probability area in central Gifu. Here we have demonstrated a tool to effectively disperse oral vaccine to wildlife. [ABSTRACT FROM AUTHOR]

Since the first confirmation of African swine fever (ASF) in domestic pig farms in South Korea in September 2019, ASF continues to expand and most notifications have been reported in wild boar populations. In this study, we first performed a spatio-temporal cluster analysis to understand ASF spread in wild boar. Secondly, generalized linear logistic regression (GLLR) model analysis was performed to identify environmental factors contributing to cluster formation. In the meantime, the basic reproduction number (R0) for each cluster was estimated to understand the growth of the epidemic. The cluster analysis resulted in the detection of 17 spatio-temporal clusters. The GLLR model analysis identified factors influencing cluster formation and indicated the possibility of estimating ASF epidemic areas based on environmental conditions. In a scenario only considering direct transmission among wild boar, R0 ranged from 1.01 to 1.5 with an average of 1.10, while, in another scenario including indirect transmission via an infected carcass, R0 ranged from 1.03 to 4.38 with an average of 1.56. We identified factors influencing ASF expansion based on spatio-temporal clusters. The results obtained would be useful for selecting priority areas for ASF control and would greatly assist in identifying efficient vaccination areas in the future. [ABSTRACT FROM AUTHOR]

The level of detail on host communities needed to understand multihost parasite invasions is an unresolved issue in disease ecology. Coarse community metrics that ignore functional differences between hosts, such as host species richness, can be good predictors of invasion outcomes. Yet if host species vary in the extent to which they maintain and transmit infections, then explicitly accounting for those differences may be important. Through controlled mesocosm experiments and modeling, we show that interspecific differences between host species are important for community-wide infection dynamics of the multihost fungal parasite of amphibians (Batrachochytrium dendrobatidis [ Bd ]), but only up to a point. The most abundant host species in our system, fire salamander larvae (Salamandra salamandra), did not maintain or transmit infections. Rather, two less abundant "auxiliary" host species, Iberian tree frog (Hyla molleri) and spiny toad (Bufo spinosus) larvae, maintained and transmitted Bd. Frogs had the highest mean rates of Bd shedding, giving them the highest contributions to the basic reproduction number, R0. Toad contributions to R0 were substantial, however, and when examining community-level patterns of infection and transmission, the effects of frogs and toads were similar. Specifying more than just host species richness to distinguish salamanders from auxiliary host species was critical for predicting community-level Bd prevalence and transmission. Distinguishing frogs from toads, however, did not improve predictions. These findings demonstrate limitations to the importance of host species identities in multihost infection dynamics. Host species that exhibit different functional traits, such as susceptibility and infectiousness, may play similar epidemiological roles in the broader community. [ABSTRACT FROM AUTHOR]

To expand on the work of previous meetings, a virtual Baveno VII workshop was organised for October 2021. Among patients with compensated cirrhosis or compensated advanced chronic liver disease (cACLD – defined at the Baveno VI conference), the presence or absence of clinically significant portal hypertension (CSPH) is associated with differing outcomes, including risk of death, and different diagnostic and therapeutic needs. Accordingly, the Baveno VII workshop was entitled "Personalized Care for Portal Hypertension". The main fields of discussion were the relevance and indications for measuring the hepatic venous pressure gradient as a gold standard, the use of non-invasive tools for the diagnosis of cACLD and CSPH, the impact of aetiological and non-aetiological therapies on the course of cirrhosis, the prevention of the first episode of decompensation, the management of an acute bleeding episode, the prevention of further decompensation, as well as the diagnosis and management of splanchnic vein thrombosis and other vascular disorders of the liver. For each of these 9 topics, a thorough review of the medical literature was performed, and a series of consensus statements/recommendations were discussed and agreed upon. A summary of the most important conclusions/recommendations derived from the workshop is reported here. The statements are classified as unchanged, changed, and new in relation to Baveno VI. [ABSTRACT FROM AUTHOR]

Studies of response learning of amphibians are scarce compared to other vertebrates. We conducted a simple experiment to evaluate response learning in a primitive anuran species, the common midwife toad (Alytes obstetricans) under an appetitive stimulus. We hypothesized that, despite the primitive character of the studied species, the animals would be able to rapidly associate a particular arm of a basic T-shaped experimental arena with the reward, and that the existing male parental care of the species would provide males greater cognitive abilities than females. The response obtained by 12 males and 13 females was statistically different than such expected by chance, suggesting a learning process. The sex of the animal, as well as the average time spent to select the correct choice, were key during the learning process. Contrary to expectations, females showed higher learning capacities than males, perhaps as a consequence of the elaborate mate selection process and the competition between females to access males in this group of amphibians. The obtained results indicate that a rapid learning capacity is highly conservative in the phylogeny, having evolved from early tetrapods to those existing today in reptiles, birds, and mammals. [ABSTRACT FROM AUTHOR]

Microplastics (MPs), a new class of pollutants that pose a threat to aquatic biodiversity, are of increasing global concern. In tandem, the amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) causing the disease chytridiomycosis is emerging worldwide as a major stressor to amphibians. We here assess whether synergies exist between this infectious disease and MP pollution by mimicking natural contact of a highly susceptible species (midwife toads, Alytes obstetricans) with a Bd-infected reservoir species (fire salamanders, Salamandra salamandra) in the presence and absence of MPs. We found that MP ingestion increases the burden of infection by Bd in a dose-dependent manner. However, MPs accumulated to a greater extent in amphibians that were not exposed to Bd, likely due to Bd-damaged tadpole mouthparts interfering with MP ingestion. Our experimental approach showed compelling interactions between two emergent processes, chytridiomycosis and MP pollution, necessitating further research into potential synergies between these biotic and abiotic threats to amphibians. [ABSTRACT FROM AUTHOR]

The recent introduction of the chytrid fungus Batrachochytrium salamandrivorans into northeastern Spain threatens salamander diversity on the Iberian Peninsula. We assessed the current epidemiological situation with extensive field sampling of urodele populations. We then sought to delineate priority regions and identify conservation units for the Iberian Peninsula by estimating the susceptibility of Iberian urodeles using laboratory experiments, evidence from mortality events in nature and captivity and inference from phylogeny. None of the 1395 field samples, collected between 2015 and 2021 were positive for Bsal and no Bsal-associated mortality events were recorded, in contrast to the confirmed occurrence of Bsal outbreak previously described in 2018. We classified five of eleven Iberian urodele species as highly susceptible, predicting elevated mortality and population declines following potential Bsal emergence in the wild, five species as intermediately susceptible with variable disease outcomes and one species as resistant to disease and mortality. We identified the six conservation units (i.e., species or lineages within species) at highest risk and propose priority areas for active disease surveillance and field biosecurity measures. The magnitude of the disease threat identified here emphasizes the need for region-tailored disease abatement plans that couple active disease surveillance to rapid and drastic actions. [ABSTRACT FROM AUTHOR]

Infectious diseases are considered major threats to biodiversity, however strategies to mitigate their impacts in the natural world are scarce and largely unsuccessful. Chytridiomycosis is responsible for the decline of hundreds of amphibian species worldwide, but an effective disease management strategy that could be applied across natural habitats is still lacking. In general amphibian larvae can be easily captured, offering opportunities to ascertain the impact of altering the abundance of hosts, considered to be a key parameter affecting the severity of the disease. Here, we report the results of two experiments to investigate how altering host abundance affects infection intensity in amphibian populations of a montane area of Central Spain suffering from lethal amphibian chytridiomycosis. Our laboratory-based experiment supported the conclusion that varying density had a significant effect on infection intensity when salamander larvae were housed at low densities. Our field experiment showed that reducing the abundance of salamander larvae in the field also had a significant, but weak, impact on infection the following year, but only when removals were extreme. While this suggests adjusting host abundance as a mitigation strategy to reduce infection intensity could be useful, our evidence suggests only heavy culling efforts will succeed, which may run contrary to objectives for conservation. [ABSTRACT FROM AUTHOR]

African Swine Fever (ASF) is one of the most complex and significant diseases from a sanitary-economic perspective currently affecting the world's swine-farming industry. ASF has been endemic in Sardinia (Italy) since 1978, and several control and eradication programmes have met with limited success. In this traditional ASF endemic area, there are three susceptible host populations for this virus sharing the same habitat: wild boar, farmed domestic pigs and non-registered free-ranging pigs (known as "brado" animals). The main goal of this study was to determine and predict fine-scale spatial interactions of this multi-host system in relation to the epidemiology of ASF in the main endemic area of Sardinia, Montes-Orgosolo. To this end, simultaneous monitoring of GPS–GSM collared wild boar and free-ranging pigs sightings were performed to predict interaction indexes through latent selection difference functions with environmental, human and farming factors. Regarding epidemiological assessment, the spatial inter-specific interaction indexes obtained here were used to correlate ASF notifications in wild boar and domestic pig farms. Daily movement patterns, home ranges (between 120.7 and 2,622.8 ha) and resource selection of wild boar were obtained for the first time on the island. Overall, our prediction model showed the highest spatial interactions between wild boar and free-ranging pigs in areas close to pig farms. A spatially explicit model was obtained to map inter-specific interaction over the complete ASF-endemic area of the island. Our approach to monitoring interaction indexes may help explain the occurrence of ASF notifications in wild boar and domestic pigs on a fine-spatial scale. These results support the recent and effective eradication measures taken in Sardinia. In addition, this methodology could be extrapolated to apply in the current epidemiological scenarios of ASF in Eurasia, where exist multi-host systems involving free-ranging pigs and wild boar. [ABSTRACT FROM AUTHOR]

Emricasan, an oral pan-caspase inhibitor, decreased portal pressure in experimental cirrhosis and in an open-label study in patients with cirrhosis and severe portal hypertension, defined as a hepatic venous pressure gradient (HVPG) ≥12 mmHg. We aimed to confirm these results in a placebo-controlled study in patients with non-alcoholic steatohepatitis (NASH)-related cirrhosis. We performed a multicenter double-blinded study, randomizing 263 patients with NASH-related cirrhosis and baseline HVPG ≥12 mmHg to twice daily oral emricasan 5 mg, 25 mg, 50 mg or placebo in a 1:1:1:1 ratio for up to 48 weeks. The primary endpoint was change in HVPG (ΔHVPG) at week 24. Secondary endpoints were changes in biomarkers (aminotransferases, caspases, cytokeratins) and development of liver-related outcomes. There were no significant differences in ΔHVPG for any emricasan dose vs. placebo (−0.21, −0.45, −0.58 mmHg, respectively) adjusted for baseline HVPG, compensation status, and non-selective beta-blocker use. Compensated patients (n = 201 [76%]) tended to have a greater decrease in HVPG (emricasan all vs. placebo, p = 0.06), the decrease being greater in those with higher baseline HVPG (p = 0.018), with a significant interaction between baseline HVPG (continuous, p = 0.024; dichotomous at 16 mmHg [median], p = 0.013) and treatment. Biomarkers decreased significantly with emricasan at week 24 but returned to baseline levels by week 48. New or worsening decompensating events (∼10% over median exposure of 337 days), progression in model for end-stage liver disease and Child-Pugh scores, and treatment-emergent adverse events were similar among treatment groups. Despite a reduction in biomarkers indicating target engagement, emricasan was not associated with improvement in HVPG or clinical outcomes in patients with NASH-related cirrhosis and severe portal hypertension. Compensated patients with higher baseline HVPG had evidence of a small treatment effect. Emricasan treatment appeared safe and well-tolerated. Cirrhosis (scarring of the liver) is the main consequence of non-alcoholic steatohepatitis (NASH). Cirrhosis leads to high pressure in the portal vein which accounts for most of the complications of cirrhosis. Reducing portal pressure is beneficial in patients with cirrhosis. We studied the possibility that emricasan, a drug that improves inflammation and scarring in the liver, would reduce portal pressure in patients with NASH-related cirrhosis and severe portal hypertension. Our results in a large, prospective, double-blind study could not demonstrate a beneficial effect of emricasan in these patients. Clinical Trials.gov # NCT02960204. • Phase III trial comparing emricasan vs. placebo in patients with NASH-related cirrhosis and severe portal hypertension. • Despite evidence of target engagement, emricasan did not reduce portal hypertension in the overall study population. • The portal pressure-reducing effect may be more evident in latter stages of portal hypertension. • Treatment-emergent adverse events were similar between emricasan and placebo. [ABSTRACT FROM AUTHOR]

Wild boar population dynamics promote the increase in numbers and distribution of the species in Eurasia, leading to a rise in the interaction with human activities, as well as generating problems with the management of certain infectious diseases, most notably African swine fever (ASF). ASF virus possesses high stability in several contaminated pork and pork products that can be a source of indirect transmission to susceptible hosts habituated to anthropogenic food waste. This transmission route is a concerning threat for the dispersion of the disease, primarily into unaffected areas given the worldwide widespread distribution of the disease and the increase of wild boar contact with humans. Thus, in this study, a straightforward tool to assess the relative risk of wild boar natural populations potentially consuming food waste is presented using synthetic data. Three risk groups were defined related to urban areas, travel, and leisure. The surrounding quality of habitat of wild boar was used to obtain the relative risk of wild boar potentially consuming anthropogenic food waste. To assign the relative risk to the corresponding risk unit, we also included the population for the urban areas group, and traffic volume for the travel risk group. The leisure group had higher scaled risk scores, followed by the urban areas group. Higher risk was found in the edges of the study area where more natural landscapes are found. The implications of this risk are discussed focusing on the context of ASF transmission. The outputs can help prioritize decision-making in terms of the improvement of preventive measures against the habituation of wild boar to anthropogenic food waste and ASFV introduction in a given study area. [ABSTRACT FROM AUTHOR]

Introduction of alien fish is a major problem for the conservation of amphibians inhabiting originally fishless mountain streams. While fish eradication programs in lakes and ponds have proven successful for the recovery of amphibian populations, there is no such information for stream-dwelling amphibians, possibly because fish removal from streams is difficult and costly. Here, we show the first case of successful recovery of a stream-dwelling amphibian (Rana iberica) in a mountain area of central Spain, following eradication of introduced brook trout (Salvelinus fontinalis) and native brown trout (Salmo trutta) translocated from downstream reaches by local anglers. Electrofishing for 12 consecutive years eradicated both fish species in the introduced area, and allowed the recovery of the R. iberica population as a result of natural recolonization from nearby streams and reintroduction of captive-reared individuals. Our results demonstrate how electrofishing can be a costly but effective method for the eradication of introduced fish and the conservation of stream-dwelling amphibians. [ABSTRACT FROM AUTHOR]

Classical swine fever has been spreading across the country since its re-emergence in Japan in 2018. Gifu Prefecture has been working diligently to control the disease through the oral vaccine dissemination targeting wild boars. Although vaccines were sprayed at 14,000 locations between 2019 and 2020, vaccine ingestion by wild boars was only confirmed at 30% of the locations. Here, we predicted the vaccine ingestion rate at each point by Random Forest modeling based on vaccine dissemination data and created prediction surfaces for the probability of vaccine ingestion by wild boar using spatial interpolation techniques. Consequently, the distance from the vaccination point to the water source was the most important variable, followed by elevation, season, road density, and slope. The area under the curve, model accuracy, sensitivity, and specificity for model evaluation were 0.760, 0.678, 0.661, and 0.685, respectively. Areas with high probability of wild boar vaccination were predicted in northern, eastern, and western part of Gifu. Leave-One-Out Cross Validation results showed that Kriging approach was more accurate than the Inverse distance weighting method. We emphasize that effective vaccination strategies based on epidemiological data are essential for disease control and that our proposed tool is also applicable for other wildlife diseases. [ABSTRACT FROM AUTHOR]

Infectious disease and climate change are considered major threats to biodiversity and act as drivers behind the global amphibian decline. This is, to a large extent, based on short-term studies that are designed to detect the immediate and strongest biodiversity responses to a threatening process. What few long-term studies are available, although typically focused on single species, report outcomes that often diverge significantly from the short-term species responses. Here, we report the results of an 18-year survey of an amphibian community exposed to both climate warming and the emergence of lethal chytridiomycosis. Our study shows that the impacts of infectious disease are ongoing but restricted to two out of nine species that form the community, despite the fact all species can become infected with the fungus. Climate warming appears to be affecting four out of the nine species, but the response of three of these is an increase in abundance. Our study supports a decreasing role of infectious disease on the community, and an increasing and currently positive effect of climate warming. We caution that if the warming trends continue, the net positive effect will turn negative as amphibian breeding habitat becomes unavailable as water bodies dry, a pattern that already may be underway. [ABSTRACT FROM AUTHOR]

Despite the important threat that emerging pathogens pose for the conservation of biodiversity as well as human health, very little is known about the adaptive potential of host species to withstand infections. We studied the quantitative genetic architecture responsible for the burden of the fungal pathogen Batrachochytrium dendrobatidis in a population of common toads in conjunction with other life-history traits (i.e., body size and development rate) that may be affected by common selective pressures. We found a significant heritable component that is associated with fungal burden, which may allow for local adaptation to this pathogen to proceed. In addition, the high genetic correlation found between fungal burden and development time suggests that both traits have to be taken into account in order to assess the adaptive response of host populations to this emerging pathogen. [ABSTRACT FROM AUTHOR]

Why does the severity of parasite infection differ dramatically across habitats? This question remains challenging to answer because multiple correlated pathways drive disease. Here, we examined habitat-disease links through direct effects on parasites and indirect effects on parasite predators (zooplankton), host diversity and key life stages of hosts. We used a case study of amphibian hosts and the chytrid fungus, Batrachochytrium dendrobatidis, in a set of permanent and ephemeral alpine ponds. A field experiment showed that ultraviolet radiation (UVR) killed the free-living infectious stage of the parasite. Yet, permanent ponds with more UVR exposure had higher infection prevalence. Two habitat-related indirect effects worked together to counteract parasite losses from UVR: (i) UVR reduced the density of parasite predators and (ii) permanent sites fostered multi-season host larvae that fuelled parasite production. Host diversitywas unlinked to hydroperiod or UVR but counteracted parasite gains; sites with higher diversity of host species had lower prevalence of infection. Thus, while habitat structure explained considerable variation in infection prevalence through two indirect pathways, it could not account for everything. This study demonstrates the importance of creating mechanistic, food web-based links between multiple habitat dimensions and disease. [ABSTRACT FROM AUTHOR]

Infectious wildlife diseases that circulate at the interface with domestic animals pose significant threats worldwide and require early detection and warning. Although animal tracking technologies are used to discern behavioural changes, they are rarely used to monitor wildlife diseases. Common disease-induced behavioural changes include reduced activity and lethargy ('sickness behaviour'). Here, we investigated whether accelerometer sensors could detect the onset of African swine fever (ASF), a viral infection that induces high mortality in suids for which no vaccine is currently available. Taking advantage of an experiment designed to test an oral ASF vaccine, we equipped 12 wild boars with an accelerometer tag and quantified how ASF affects their activity pattern and behavioural fingerprint, using overall dynamic body acceleration. Wild boars showed a daily reduction in activity of 10–20% from the healthy to the viremia phase. Using change point statistics and comparing healthy individuals living in semi-free and free-ranging conditions, we show how the onset of disease-induced sickness can be detected and how such early detection could work in natural settings. Timely detection of infection in animals is crucial for disease surveillance and control, and accelerometer technology on sentinel animals provides a viable complementary tool to existing disease management approaches. [ABSTRACT FROM AUTHOR]

Estimating demographic parameters like survival or recruitment provides insight into the state and trajectory of populations, but understanding the contexts influencing those parameters, including both biotic and abiotic factors, is particularly important for management and conservation. At a high elevation national park in Central Spain, common toads (Bufo bufo) are apparently taking advantage of the near-extirpation of the midwife toad (Alyles obstetricans), as colonization into new breeding ponds is evident. Within this scenario, we expected demographic parameters of common toad populations to be affected favorably by the putative release from competition. However, we found the population growth rate was negative in 4 of 5 years at the long-standing population; survival probability at the long-standing population and newly-colonised breeding ponds was lower than reported for other toads living at high elevations and the probability of recruitment was inadequate to compensate for the survival rate in maintaining a positive trajectory for either of the breeding ponds. We assessed weather covariates and disease for their contribution to the context that may be limiting the common toad's successful use of the niche vacated by the midwife toad. [ABSTRACT FROM AUTHOR]

The aim of this work was to use standardized digital cartography of vegetation coverage to test whether or not the predicted range of habitat suitability for wild boar in Bulgaria coincides with the georeferenced/presence records of this species. The predicted range of habitat suitability based on potential biological resources in Bulgaria encompasses 13 land uses from the CORINE program, being "Broad-leaved forests" (23432 km² ) the most representative. The total potential resources for wild boar correspond to 57.54 % of the country area. A high level of correlation (0.86) was found between inverse distance of wild boars presence and habitat suitability areas. A significant level of correlation (0.71, p < 0.0001) per Bulgarian region between area of habitat suitability category 2 (resources suitable for use as both food and shelter) and number of wild boar was also found. Suitable wild boar habitat on borders appeared as the most relevant parameter for evaluating the risk of introduction of diseases by wild boar into the European Union from neighbouring countries. Despite being the longest (608 km), the Bulgaria-Romania border did not represent the most important corridor for wild boar since only 12.78 % of its surface is suitable habitat; the percentage of the importance of this border edges the passage of wild boar is 20.63 %. The Bulgaria-Macedonia (FYROM) border must be regarded as the most important passageway for wild boar (96.88 %), with 148 km of border and 12.34 % of its surface area of suitable habitat. Our findings could be highly useful for developing adequate strategies for wildlife management practices on large spatial scales, as well as for the control of wildlife and its habitats (territorial integration and spatial planning according to the casuistry of the zone), and relationships between wildlife and other human interests. [ABSTRACT FROM AUTHOR]

Cirrhosis is an increasing cause of morbidity and mortality in more developed countries, being the 14th most common cause of death worldwide but fourth in central Europe. Increasingly, cirrhosis has been seen to be not a single disease entity, but one that can be subclassified into distinct clinical prognostic stages, with 1-year mortality ranging from 1% to 57% depending on the stage. We review the current understanding of cirrhosis as a dynamic process and outline current therapeutic options for prevention and treatment of complications of cirrhosis, on the basis of the subclassification in clinical stages. The new concept in management of patients with cirrhosis should be prevention and early intervention to stabilise disease progression and to avoid or delay clinical decompensation and the need for liver transplantation. The challenge in the 21st century is to prevent the need for liver transplantation in as many patients with cirrhosis as possible. INSET: Panel: Indications and contraindications for liver.... [ABSTRACT FROM AUTHOR]

In Memoriam: Roberto J. Groszmann, MD (1939-2021). [Extracted from the article]

Amphibian chytridiomycosis, caused by the chytrid fungus Batrachochytrium dendrobatidis (Bd), is an emerging infectious disease that widely threatens amphibian biodiversity. However, population-level outcomes following the introduction of the pathogen are highly context dependent and are mediated by a broad suite of biotic and abiotic variables. Here, we examine the effect of the introduction of Bd on native island populations of the IUCN red-listed amphibian species Alytes muletensis, the Mallorcan midwife toad. We show that the outcome of pathogen introduction is not only dependent on biotic factors, but is also dependent on environmental factors that vary across local scales. Our experimental infections confirm that the genotype of Bd occurring on Mallorca is hypovirulent in A. muletensis when compared against the lineage found occurring on mainland Iberia. Long-term population data show that A. muletensis populations on the island are increasing overall, but trends in highly infected populations are conflicting. We use mathematical models and field data to demonstrate that this divergence in population response to infection can be explained by local environmental differences between infected sites, whereas pathogen genetics, host genetics, and intrinsic epidemiological dynamics driven by fungal load are less likely to be the cause of these differing population trajectories. Our results illustrate the need to take into account the appropriate environmental scale and context when assessing the risk that an emerging pathogen presents to a naïve population or species. [ABSTRACT FROM AUTHOR]

Anthropogenic disturbances have been implicated in the rapid decline of amphibians. Disturbances, such as disease and poor water quality, might cause changes in the physiology of amphibians resulting in chronic stress, which can result in decreased growth and development as well as immunosuppression. In amphibians, corticosterone (CORT) is the main hormone released in response to stressors. We took the first steps towards validating a new, non-invasive, technique to assay CORT in amphibians using a water-borne collection method previously used only with fish. In validation of this technique, we found a significant positive correlation between release rates of water-borne CORT and levels of CORT in circulating plasma in adults of the San Marcos salamander, Eurycea nana, and the common midwife toad, Alytes obstetricans. These results indicate that water-borne CORT can be used as a proxy for plasma CORT. Additionally, we examined basic background information on the physiological states of these two species. We found that captive-reared salamanders had significantly lower release rates of CORT than field-collected salamanders. Field-collected salamanders had significantly higher CORT release rates 24 h after capture and transfer to the laboratory. For tadpoles, we found that field-collected tadpoles did not have significantly different CORT release rates than those maintained in the laboratory for four months. Our research indicates that this method of water-borne hormone collection should be viable for many species of amphibians; however, further validation via adrenocorticotropic hormone (ACTH) challenges is required. This method can be a useful tool for assessing the physiological state of laboratory and field populations of amphibians and the effects of urbanization, pesticides and diseases. An important benefit of this method is that it allows for repeated measures of the same individuals and can be less stressful than drawing blood. [ABSTRACT FROM AUTHOR]

Shneider BL, Bosch J, de Franchis R, Emre SH, Groszmann RJ, Ling SC, Lorenz JM, Squires RH, Superina RA, Thompson AE, Mazariegos GV. Portal Hypertension in Children: Expert Pediatric Opinion on the Report of the Baveno V Consensus Workshop on Methodology of Diagnosis and Therapy in Portal Hypertension. Abstract: Complications of portal hypertension in children lead to significant morbidity and are a leading indication for consideration of liver transplantation. Approaches to the management of sequelae of portal hypertension are well described for adults and evidence-based approaches have been summarized in numerous meta-analyses and conferences. In contrast, there is a paucity of data to guide the management of complications of portal hypertension in children. An international panel of experts was convened on April 8, 2011 at The Children's Hospital of Pittsburgh of UPMC to review and adapt the recent report of the Baveno V Consensus Workshop on the Methodology of Diagnosis and Therapy in Portal Hypertension to the care of children. The opinions of that expert panel are reported. [ABSTRACT FROM AUTHOR]

The article explores the wild boar population in the Iberian Peninsula, which was estimated by the authors using the hunting bag statistics from Spain and Portugal. In the said countries, wild boar is a valuable part of the economic and hunting resource like that in Spain from 2006-2007 where 29.3 million Euros were generated from wild boar hunting. In the density and unified habitat study the authors performed, they found that CORINE land uses significantly influence wild boar presence in a given area and that the average density of wild boars within their potential habitat is 0.38 per kilometer squared.

Purpose: To assess the effect of tezosentan, a parenteral dual ET receptor antagonist, on splanchnic and systemic hemodynamics in patients with cirrhosis. In addition, the safety, pharmacokinetics, and pharmacodynamics of tezosentan were evaluated. Methods: The population consisted of patients with cirrhosis with clinically significant portal hypertension. This was a randomized, double-blind, multicenter study. The patients were randomized 3:1 to tezosentan (3 mg/h for 2-3 h) or placebo. HVPG, hepatic blood flow (HBF, ICG method), and systemic arterial pressures were measured before and after tezosentan administration. Plasma concentrations of tezosentan and ET-1 were determined peripherally and in the hepatic vein. Results: Eighteen patients received tezosentan and six placebo. Baseline clinical, biochemical, and hemodynamic characteristics were balanced between the two groups. There was no significant treatment effect on HVPG. The extraction ratio (0.31), the plasma clearance of ICG (280 ml/min), and the HBF (1,430 ml/min) did not show any relevant changes during the infusion of tezosentan, and there were no differences between placebo- and tezosentan-treated patients. A linear relationship was observed between the maximum-fold increase in ET-1 concentration and the steady-state tezosentan plasma concentration ( r = 0.82). There was a strong correlation ( r = 0.88) between plasma clearance of ICG and that of tezosentan (10.2 l/h). Arterial pressure and heart rate did not significantly change in either group. Conclusion: In patients with cirrhosis, a 2- to 3-h tezosentan infusion was safe and well tolerated but did not change the HVPG. Tezosentan infusion had no influence on the extraction ratio and plasma clearance of ICG and did not change HBF. [ABSTRACT FROM AUTHOR]

Background: Rescuing amphibian diversity is an achievable conservation challenge. Disease mitigation is one essential component of population management. Here we assess existing disease mitigation strategies, some in early experimental stages, which focus on the globally emerging chytrid fungus Batrachochytrium dendrobatidis. We discuss the precedent for each strategy in systems ranging from agriculture to human medicine, and the outlook for each strategy in terms of research needs and long-term potential. Results: We find that the effects of exposure to Batrachochytrium dendrobatidis occur on a spectrum from transient commensal to lethal pathogen. Management priorities are divided between (1) halting pathogen spread and developing survival assurance colonies, and (2) prophylactic or remedial disease treatment. Epidemiological models of chytridiomycosis suggest that mitigation strategies can control disease without eliminating the pathogen. Ecological ethics guide wildlife disease research, but several ethical questions remain for managing disease in the field. Conclusions: Because sustainable conservation of amphibians in nature is dependent on long-term population persistence and co-evolution with potentially lethal pathogens, we suggest that disease mitigation not focus exclusively on the elimination or containment of the pathogen, or on the captive breeding of amphibian hosts. Rather, successful disease mitigation must be context specific with epidemiologically informed strategies to manage already infected populations by decreasing pathogenicity and host susceptibility. We propose population level treatments based on three steps: first, identify mechanisms of disease suppression; second, parameterize epizootiological models of disease and population dynamics for testing under semi-natural conditions; and third, begin a process of adaptive management in field trials with natural populations. [ABSTRACT FROM AUTHOR]

Acute variceal bleeding (AVB) is a life-threatening complication in patients with cirrhosis. Hemostatic therapy of AVB includes early administration of vasoactive drugs that should be combined with endoscopic therapy, preferably banding ligation. However, failure to control bleeding or early rebleed within 5 days still occurs in 15-20% of patients with AVB. In these cases, a second endoscopic therapy may be attempted (mild bleeding in a hemodynamically stable patient) or we can use a balloon tamponade as a bridge to definitive derivative treatment (i.e., a transjugular intrahepatic portosystemic shunt). Esophageal balloon tamponade provides initial control in up to 80% of AVB, but it carries a high risk of major complications, especially in cases of long duration of tamponade (>24 h) and when tubes are inserted by inexperienced staff. Preliminary reports suggest that self-expandable covered esophageal metallic stents effectively control refractory AVB (i.e., ongoing bleeding despite pharmacological and endoscopic therapy ormassive bleeding precluding endoscopic therapy) with a low incidence of complications. Thus, covered self-expanding metal stents may represent an alternative to the Sengstaken-Blakemore balloon for the temporary control of bleeding in treatment failures. Further studies are required to determine the role of this new device in AVB. [ABSTRACT FROM AUTHOR]

We address the question of whether female preference exerts selection on male calling energy (souce level). We investigate whether female midwife toads express a preference between advertisement calls that have different source levels but that reach them with similar intensities (due to differences in distance). Females were presented with pairs of recordings of identical synthetic calls, recorded at the same location in the field site, and reaching the microphone at similar sound levels (69 dB peak SPL). Stimulus 'Hi source level' was recorded two meters away from the sound source but emitted with higher sound intensity, and stimulus 'Low source level' was recorded one meter away from the source but emitted with lower source level. We use a protocol of 'playback setpoints' for tests with no a priori expectations. We did not find evidence of female preference for source level in either species. Alytes obstetricans females reversed their choice when differences in intensity were lower, suggesting lower selectivity during the approach phase. We conclude that any selection on male call intensity is unlikely to occur, possibly being severely limited by calling location (male–female distance) and by transmission conditions. [ABSTRACT FROM AUTHOR]

A response by Guadalupe Garcia-Tsao and Jaime Bosch to a letter to the editor about their article "Management of Varices and Variceal Hemorrhage in Cirrhosis" in the March 4, 2010 issue "New England Journal of Medicine" is presented.

The article discusses the treatment of varices and variceal hemorrhage in patients with cirrhosis. According to the authors, the three key areas of management include primary prophylaxis to prevent the initial episode of variceal hemorrhage, treatment of the acude bleeding episode, and secondary prophylaxis to prevent recurrent variceal hemorrhage. They that vasopressin and somatostatin are given orally and must be restricted in an acute care setting. The best way to stratify risk is to use the hepatic venous pressure gradient in measuring portal pressure. Shunt therapy can be considered in treating hemorrhage that requires frequent blood transfusions.

Ecology Letters (2010) 13: 372–382 Amphibian chytridiomycosis is a disease caused by the fungus Batrachochytrium dendrobatidis ( Bd). Whether Bd is a new emerging pathogen (the novel pathogen hypothesis; NPH) or whether environmental changes are exacerbating the host-pathogen dynamic (the endemic pathogen hypothesis; EPH) is debated. To disentangle these hypotheses we map the distribution of Bd and chytridiomycosis across the Iberian Peninsula centred on the first European outbreak site. We find that the infection-free state is the norm across both sample sites and individuals. To analyse this dataset, we use Bayesian zero-inflated binomial models to test whether environmental variables can account for heterogeneity in both the presence and prevalence of Bd, and heterogeneity in the occurrence of the disease, chytridiomycosis. We also search for signatures of Bd-spread within Iberia using genotyping. We show (1) no evidence for any relationship between the presence of Bd and environmental variables, (2) a weak relationship between environmental variables and the conditional prevalence of infection, (3) stage-dependent heterogeneity in the infection risk, (4) a strong association between altitude and chytridiomycosis, (5) multiple Iberian genotypes and (6) recent introduction and spread of a single genotype of Bd in the Pyrenees. We conclude that the NPH is consistent with the emergence of Bd in Iberia. However, epizootic forcing of infection is tied to location and shaped by both biotic and abiotic variables. Therefore, the population-level consequences of disease introduction are explained by EPH-like processes. This study demonstrates the power of combining surveillance and molecular data to ascertain the drivers of new emerging infections diseases. [ABSTRACT FROM AUTHOR]

The article discusses the treatment for esophageal varices. Topics discussed include the risk of variceal bleeding in patients suffering with advanced chronic liver disease based on the portal hypertension degree, the application of pre-primary prophylax use to prevent the development of varices, and the use of transjugular intrahepatic portosystemic shunt (TIPS) as rescue therapy and measurement to avoid rebleeding.

Population genetics of the amphibian pathogen Batrachochytrium dendrobatidis ( Bd) show that isolates are highly related and globally homogenous, data that are consistent with the recent epidemic spread of a previously endemic organism. Highly related isolates are predicted to be functionally similar due to low levels of heritable genetic diversity. To test this hypothesis, we took a global panel of Bd isolates and measured (i) the genetic relatedness among isolates, (ii) proteomic profiles of isolates, (iii) the susceptibility of isolates to the antifungal drug caspofungin, (iv) the variation among isolates in growth and phenotypic characteristics, and (v) the virulence of isolates against the European common toad Bufo bufo. Our results show (i) genotypic differentiation among isolates, (ii) proteomic differentiation among isolates, (iii) no significant differences in susceptibility to caspofungin, (iv) differentiation in growth and phenotypic/morphological characters, and (v) differential virulence in B. bufo. Specifically, our data show that Bd isolates can be profiled by their genotypic and proteomic characteristics, as well as by the size of their sporangia. Bd genotypic and phenotypic distance matrices are significantly correlated, showing that less-related isolates are more biologically unique. Mass spectrometry has identified a set of candidate genes associated with inter-isolate variation. Our data show that, despite its rapid global emergence, Bd isolates are not identical and differ in several important characters that are linked to virulence. We argue that future studies need to clarify the mechanism(s) and rate at which Bd is evolving, and the impact that such variation has on the host–pathogen dynamic. [ABSTRACT FROM AUTHOR]

Emerging infectious diseases (EIDs) may indirectly influence community structure by altering biotic interactions in which affected species participate. This kind of indirect effects has received little attention to date, although recent research suggest they may not be infrequent. Chytridiomycosis is an EID that is affecting amphibian assemblages worldwide. Here we present the first (to our knowledge) field evidence of its indirect effect on assemblage structure through the disruption of a biotic interaction. We have documented an expansion of the common toad ( Bufo bufo) after chytridiomycosis nearly extirpated the midwife toad ( Alytes obstetricans) in Peñalara Natural Park (Central Spain). Bufo bufo has significantly increased its number of breeding sites. All newly occupied breeding ponds were colonized once the large numbers of large, overwintering A. obstetricans tadpoles they had previously held disappeared. An experiment demonstrated that breeding B. bufo adults strongly avoided laying eggs in water containing A. obstetricans tadpoles, accounting for observed patterns of pond use. A second experiment failed to show any predation by large A. obstetricans tadpoles on B. bufo eggs, but other researchers have documented reductions in condition, growth and survival of B. bufo larvae caused by the presence of A. obstetricans tadpoles. In Peñalara, chytridiomycosis attacks B. bufo too, but its effect on it has been quite less severe than on A. obstetricans. Our findings show how, besides any chytridiomycosis direct effects, interspecific differences in its impact may alter assemblage–influencing biotic interactions and, hence, assemblage structure in indirect ways. [ABSTRACT FROM AUTHOR]

We quantify and compare female preference for two different acoustic parameters of the male advertisement call in two species of midwife toads where females select mates based on call characteristics. The parameters compared were: call repetition rate, a highly variable parameter associated with male–male competition, and call dominant frequency, a parameter with low variability related to male size. We also tested whether intensity of female preference was similar when the alternate choices were perceived at high overall intensities (close range) or lower overall intensities (long range). We use ‘Playback setpoints’ a new experimental protocol based on two-speaker playback tests with the female placed in a ferret wheel (treadmill) that keeps her equidistant from the two speakers. The protocol measures preference as a trade-off with perceived call intensity: the ‘a priori’ preferred parameter is not broadcast initially, and the female initially walks towards the speaker emitting the inferior parameter. When the female walks towards this speaker the intensity of the opposite speaker is gradually increased until the female turns around and starts her approach towards the ‘a priori’ preferred parameter. At this point the differences in sound intensity between the speakers are measured, and the difference is considered to be a measure of female preference. Our results show that female preference for call repetition rate is significantly more intense than that for dominant frequency. Similarly, we find that female preference intensity is higher when stimuli are broadcast at higher overall intensity indicating that females are more selective at close range. [Copyright &y& Elsevier]

Call-timing mechanisms among anuran males calling within choruses are frequent, and previous studies have indicated that midwife toad females respond preferentially to these mechanisms. The results of multi-speaker tests performed here with midwife toads suggest that the temporal order of male calls within a dense chorus can determine the ability of females to locate the most attractive calls (in this instance the low-frequency calls emitted by larger males). When call emission was regular in the multi-speaker tests, most females chose the most attractive option (i.e., the speaker emitting the lower-frequency call). When call emission was not regular, however, most females failed to reach the most attractive option, selecting the speaker that emitted immediately after that emitting the most attractive call. These results support the idea that there may be benefits for smaller males that emit their less attractive calls close to those of larger, more attractive males in dense choruses. Less attractive males could exploit the attractiveness of nearby larger males calls by alternating their calls in an unordered sequence to reach receptive females. [ABSTRACT FROM AUTHOR]

Amphibians are declining worldwide because of multiple factors, including human-mediated introduction of fishes into naturally fishless areas. Although several studies have focused on the effect of exotic fishes on native amphibians breeding in ponds or lakes, little is known about their effects on stream-breeding species. We studied the effects of introductions of native brown trout (Salmo trutta ) and exotic brook trout (Salvelinus fontinalis ) on the stream-breeding, endemic Iberian frog ( Rana iberica ) in a protected area in central Spain. We assessed occurrence patterns of tadpoles and salmonids and compared habitat use of the three species. We also determined experimentally whether chemical cues from salmonids elicited antipredator behavior in tadpoles. Finally, we assessed the relative influence of tadpole habitat preferences, differences in salmonid species, and invasion geography on tadpole occurrence. Despite widely overlapping habitat preferences, tadpoles and trout did not coexist, with the former restricted to fishless habitats. Tadpoles detected chemical cues from both trout species and reacted by decreasing their activity, although the response toward the native brown trout was stronger. The residual distribution of Iberian frogs in Peñalara is better explained by the geography of fish invasions than by the fish species involved. Measures such as fish extirpation from certain areas, aimed at recovering lost habitat and improving connectivity among remaining populations of Iberian frogs, seem critical for the species' long-term survival in central Spain. [ABSTRACT FROM AUTHOR]

Chytridiomycosis is a fatal disease associated with amphibian population declines and extinctions worldwide. In a protected area in central Spain, the Peñalara Natural Park, the disease almost extirpated the population of Alytes obstetricans over only a few years, but did not apparently affect other amphibians. We present new observations documenting the occurrence of the disease in other species. In 2001-2003 we collected over 400 larvae or recently metamorphosed individuals of Salamandra salamandra and also several dead individuals of Bufo bufo. The analysis of the skin of post-metamorphic specimens revealed the presence of chytrid sporangia and discharge tubes in both species. According to measures of larval abundances in 1999 and 2003 the population of S. salamandra has suffered a marked decline but no significant trend was observed for B. bufo. We discuss the possible role of chytridiomycosis in the decline of S. salamandra and comment on the differential susceptibility exhibited by various species in the amphibian community at Penalara. [ABSTRACT FROM AUTHOR]

Gastroesophageal variceal bleeding is a complication of liver cirrhosis with a mortality rate of 20% at 6 weeks. Initial treatment includes blood volume restitution, antibiotic prophylaxis, and administration of vasoactive drugs to decrease portal pressure with the aim to arrest the bleeding and prevent rebleeding. Effective drugs include terlipressin and somatostatin, which should be started at admission and maintained for 2–5 days. Early endoscopic diagnosis ( [ABSTRACT FROM AUTHOR]

The intensity of female preference for call characteristics is measured in two-speaker playback tests with female Iberian midwife toads‘ Alytes cisternasii’ using an experimental design that allows quantitative comparisons across characters. Female preferences do not appear to be symmetrical above and below the population mean, female preference being more efficient at discriminating against low quality competing males that at selecting optimum males among good ones. Female preference is significantly more effective selecting males calling at higher call rates (a highly variable call characteristic probably related to the physical state of the male) rather than selecting calls of low dominant frequency (a characteristic of low intra-individual variation, related to male size and age). [ABSTRACT FROM AUTHOR]