Alpine salamanders at risk? The current status of an emerging fungal pathogen.

Amphibians globally suffer from emerging infectious diseases like chytridiomycosis caused by the continuously spreading chytrid fungi. One is Batrachochytrium salamandrivorans (Bsal) and its disease ‒ the 'salamander plague' ‒ which is lethal to several caudate taxa. Recently introduced into Western Europe, long distance dispersal of Bsal, likely through human mediation, has been reported. Herein we study if Alpine salamanders (Salamandra atra and S. lanzai) are yet affected by the salamander plague in the wild. Members of the genus Salamandra are highly susceptible to Bsal leading to the lethal disease. Moreover, ecological modelling has shown that the Alps and Dinarides, where Alpine salamanders occur, are generally suitable for Bsal. We analysed skin swabs of 818 individuals of Alpine salamanders and syntopic amphibians at 40 sites between 2017 to 2022. Further, we compiled those with published data from 319 individuals from 13 sites concluding that Bsal infections were not detected. Our results suggest that the salamander plague so far is absent from the geographic ranges of Alpine salamanders. That means that there is still a chance to timely implement surveillance strategies. Among others, we recommend prevention measures, citizen science approaches, and ex situ conservation breeding of endemic salamandrid lineages.

The impacts of water quality on the amphibian chytrid fungal pathogen: A systematic review.

The pathogenic fungus Batrachochytrium dendrobatidis has caused declines of amphibians worldwide. Yet our understanding of how water quality influences fungal pathogenicity is limited. Here, we reviewed experimental studies on the effect of water quality on this pathogen to determine which parameters impacted disease dynamics consistently. The strongest evidence for protective effects is salinity which shows strong antifungal properties in hosts at natural levels. Although many fungicides had detrimental effects on the fungal pathogen in vitro, their impact on the host is variable and they can worsen infection outcomes. However, one fungicide, epoxiconazole, reduced disease effects experimentally and likely in the field. While heavy metals are frequently studied, there is weak evidence that they influence infection outcomes. Nitrogen and phosphorous do not appear to impact pathogen growth or infection in the amphibian host. The effects of other chemicals, like pesticides and disinfectants on infection were mostly unclear with mixed results or lacking an in vivo component. Our study shows that water chemistry does impact disease dynamics, but the effects of specific parameters require more investigation. Improving our understanding of how water chemistry influences disease dynamics will help predict the impact of chytridiomycosis, especially in amphibian populations affected by land use changes.

Are novel or locally adapted pathogens more devastating and why? Resolving opposing hypotheses.

There is a rich literature highlighting that pathogens are generally better adapted to infect local than novel hosts, and a separate seemingly contradictory literature indicating that novel pathogens pose the greatest threat to biodiversity and public health. Here, using Batrachochytrium dendrobatidis, the fungus associated with worldwide amphibian declines, we test the hypothesis that there is enough variance in "novel" (quantified by geographic and phylogenetic distance) host-pathogen outcomes to pose substantial risk of pathogen introductions despite local adaptation being common. Our continental-scale common garden experiment and global-scale meta-analysis demonstrate that local amphibian-fungal interactions result in higher pathogen prevalence, pathogen growth, and host mortality, but novel interactions led to variable consequences with especially virulent host-pathogen combinations still occurring. Thus, while most pathogen introductions are benign, enough variance exists in novel host-pathogen outcomes that moving organisms around the planet greatly increases the chance of pathogen introductions causing profound harm.

Widespread occurrence of the amphibian chytrid panzootic lineage in Uruguay is constrained by climate.

The amphibian chytrid fungus Batrachochytrium dendrobatidis (Bd) causes chytridiomycosis, a disease among the main causes of amphibian declines worldwide. However, Bd studies on Neotropical amphibians from temperate areas are scarce. We present a comprehensive survey of Bd in Uruguay, in temperate central eastern South America, carried out between 2006 and 2014. Skin swabs of 535 specimens of 21 native and exotic frogs were tested by PCR. We used individual-level data to examine the relationship between infection, climatic variables, and their effects on body condition and the number of prey items found in stomach contents. Infection was widespread in free-ranging anurans with an overall prevalence of 41.9%, detected in 15 native species, wild American bullfrogs Aquarana catesbeiana, and captive specimens of Ceratophrys ornata and Xenopus laevis. Three haplotypes of the Bd ITS region were identified in native amphibians, all belonging to the global panzootic lineage (BdGPL), of which only one was present in exotic hosts. Despite high infection frequencies in different anurans, we found no evidence of morbidity or mortality attributable to chytridiomycosis, and we observed no discernible impact on body condition or consumed prey. Climatic conditions at the time of our surveys suggested that the chance of infection is associated with monthly mean temperature, mean humidity, and total precipitation. Temperatures below 21°C combined with moderate humidity and pronounced rainfall may increase the likelihood of infection. Multiple haplotypes of BdGPL combined with high frequencies of infection suggest an enzootic pattern in native species, underscoring the need for continued monitoring.

Glove decontamination procedures to prevent pathogen and DNA cross-contamination among frogs.

Working with aquatic organisms often requires handling multiple individuals in a single session, potentially resulting in cross-contamination by live pathogens or DNA. Most researchers address this problem by disposing of gloves between animals. However, this generates excessive waste and may be impractical for processing very slippery animals that might be easier to handle with cotton gloves. We tested methods to decontaminate cotton or nitrile gloves after contamination with cultured Batrachochytrium dendrobatidis (Bd) or after handling heavily Bd-infected Xenopus laevis with layered cotton and nitrile gloves. Bleach eliminated detectable Bd DNA from culture-contaminated nitrile gloves, but gloves retained detectable Bd DNA following ethanol disinfection. After handling a Bd-infected frog, Bd DNA contamination was greatly reduced by removal of the outer cotton glove, after which either bleach decontamination or ethanol decontamination followed by drying hands with a paper towel lowered Bd DNA below the detection threshold of our assay. These results provide new options to prevent pathogen or DNA cross-contamination, especially when handling slippery aquatic organisms. However, tradeoffs should be considered when selecting an animal handling procedure, such as the potential for cotton gloves to abrade amphibian skin or disrupt skin mucus. Disposing of gloves between animals should remain the gold standard for maintaining biosecurity in sensitive situations.

Paranannizziopsis spp. Infection in Wild Vipers, Europe.

We describe the detection of Paranannizziopsis sp. fungus in a wild population of vipers in Europe. Fungal infections were severe, and 1 animal likely died from infection. Surveillance efforts are needed to better understand the threat of this pathogen to snake conservation.

White-nose syndrome, winter duration, and pre-hibernation climate impact abundance of reproductive female bats.

White-nose syndrome (WNS) is an infectious disease that disrupts hibernation in bats, leading to premature exhaustion of fat stores. Though we know WNS does impact reproduction in hibernating female bats, we are unsure how these impacts are exacerbated by local climate factors. We compiled data from four southeastern U.S. states and used generalized linear mixed effects models to compare effects of WNS, pre-hibernation climate variables, and winter duration on the number of reproductive females in species across the range of WNS susceptibility. We predicted we would see a decline in the number of reproductive females in WNS-susceptible species, with the effect exaggerated by longer winter durations and pre-hibernation climate variables that lead to reductions in foraging. We found that the number of reproductive females in WNS-susceptible species was positively correlated with pre-hibernation local climate conditions conducive to foraging; however, WNS-susceptible species experienced an overall decline with the presence of WNS and as winter duration increased. Our long-term dataset provides evidence that pre-hibernation climate, specifically favorable summer weather conditions for foraging, greatly influences the reproduction, regardless of WNS status.

Comparison of the antifungal activity of the pyrimidine analogs flucytosine and carmofur against human-pathogenic dematiaceous fungi.

Chromoblastomycosis (CBM) and pheohyphomycosis (PHM) are the most common implantation mycoses caused by dematiaceous fungi. In the past, flucytosine (5-FC) has been used to treat CBM, but development of resistance is common. Carmofur belongs to the same class as 5-FC and has in vitro inhibitory activity against the main agents of CBM and PHM. The aim of this study was to compare the action of these two pyrimidine analog drugs against CBM and PHM agents. The minimum inhibitory concentration (MIC) and the selectivity index based on cytotoxicity tests of these two drugs against some agents of these mycoses were determined, with carmofur presenting a higher selectivity index than 5-FC. Carmofur demonstrated here synergistic interactions with itraconazole and amphotericin B against Exophiala heteromorpha, Fonsecaea pedrosoi, Fonsecaea monophora, and Fonsecaea nubica strains. Additionally, carmofur plus itraconazole demonstrated here synergism against a Phialophora verrucosa strain. To evaluate the development of carmofur resistance, passages in culture medium containing subinhibitory concentrations of this pyrimidine analog were carried out, followed by in vitro susceptibility tests. Exophiala dermatitidis quickly developed resistance, whereas F. pedrosoi took seven passages in carmofur-supplemented medium to develop resistance. Moreover, resistance was permanent in E. dermatitidis but transient in F. pedrosoi. Hence, carmofur has exhibited certain advantages, albeit accompanied by limitations such as the development of resistance, which was expected as with 5-FC. This underscores its therapeutic potential in combination with other drugs, emphasizing the need for a meticulous evaluation of its application in the fight against dematiaceous fungi.

Itraconazole in human medicine and veterinary practice.

Diagnosis and management of fungal infections are challenging in both animals and humans, especially in immunologically weakened hosts. Due to its broad spectrum and safety profile when compared to other antifungals, itraconazole (ITZ) has been widely used in the treatment and prophylaxis of fungal infections, both in human and veterinary medicine. The dose and duration of management depend on factors such as the type of fungal pathogen, the site of infection, sensitivity to ITZ, chronic stages of the disease, the health status of the hosts, pharmacological interactions with other medications and the therapeutic protocol used. In veterinary practice, ITZ doses generally vary between 3 mg/kg and 50 mg/kg, once or twice a day. In humans, doses usually vary between 100 and 400 mg/day. As human and veterinary fungal infections are increasingly associated, and ITZ is one of the main medications used, this review addresses relevant aspects related to the use of this drug in both clinics, including case reports and different clinical aspects available in the literature.

Chemical disinfection as a simple and reliable method to control the amphibian chytrid fungus at breeding points of endangered amphibians.

Chytridiomycosis caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd) is pushing amphibians towards extinction. Whilst mitigation methods were suggested a decade ago, we lack field trials testing their efficacy. We used the agrochemical fungicide, tebuconazole, to treat Bd infected breeding waterbodies of an endangered species that is highly susceptible to the fungus. Just two applications of tebuconazole led to a significant reduction in infection loads in the vast majority of sites, and at six sites the disinfection remained one/two-years post-application. Tebuconazole values drastically decreased in the waterbodies within a week after application, with no significant effects on their hydrochemical and hydrobiological characteristics. Although the use of chemicals in natural populations is undesirable, the growing existential threat to amphibians all over the world indicates that effective interventions in selected populations of endangered species are urgently needed.

Fusariosis in burn patients: A systematic review of case reports.

Burns can cause skin damage, facilitating the entry of fungi and other microorganisms into the body, leading to infections. Fusarium is a fungus capable of infecting individuals with burn injuries. Diagnosing and treating Fusarium infections in burn patients can be challenging due to the manifestation of nonspecific symptoms. This study aims to investigate case reports and case series from published literature describing Fusarium infection in burned patients, in order to assess treatment regimens, clinical outcomes, and make recommendations for future management. We conducted searches on Web of Science, PubMed, ScienceDirect, and Medline for all case reports and case series containing keywords 'Burn', 'Burns', 'Burned', 'Fusarium', or 'Fusariosis' in the title or abstract. All burn patients who developed Fusarium fungal infections between January 1974 and March 2023 were included in the study. Demographic and clinical data were analyzed retrospectivity. The final analysis incorporates 24 case reports encompassing a total of 87 burn patients with Fusarium infection. Patient ages ranged from one to 85 years, with the majority being male (53%). The median percentage of burn surface area was 78%, and the skin in the face, upper limbs, and lower limbs were the most commonly infected sites. Fungal infections appeared around 10 days after the burn injury on average. The majority of the patients were identified through culture or histopathology. The Fusarium dimerum species complex, which was found in nine patients, was the most frequently identified Fusarium species complex. Amphotericin B was the most preferred treatment drug, followed by voriconazole, and 62% of patients underwent debridement. In our study, 23 patients (37%) died from fungal infections. Implementing early and effective treatment protocols targeting Fusarium spp. in burn treatment units can significantly reduce mortality rates. It is critical to enhance the understanding of fusariosis epidemiology and emphasize the importance of maintaining a high clinical suspicion for this condition in burn patients.

Coevolution of a generalist pathogen with many hosts: the case of the amphibian chytrid Batrachochytrium dendrobatidis.

Generalist pathogens maintain infectivity in numerous hosts; how this broad ecological niche impacts host-pathogen coevolution remains to be widely explored. Batrachochytrium dendrobatidis (Bd) is a highly generalist pathogenic fungus that has caused devastating declines in hundreds of amphibian species worldwide. This review examines amphibian chytridiomycosis host-pathogen interactions and available evidence for coevolution between Bd and its numerous hosts. We summarize recent evidence showing that Bd genotypes vary in geographic distribution and virulence, and that amphibian species also vary in Bd susceptibility according to their geographic distribution. How much variation can be explained by phenotypic plasticity or genetic differences remains uncertain. Recent research suggests that Bd genotypes display preferences for specific hosts and that some hosts are undergoing evolution as populations rebound from Bd outbreaks. Taken together, these findings suggest the potential for coevolution to occur and illuminate a path for addressing open questions through integrating historical and contemporary genetic data.

Advances in Managing Chytridiomycosis for Australian Frogs: Gradarius Firmus Victoria.

Extensive knowledge gains from research worldwide over the 25 years since the discovery of chytridiomycosis can be used for improved management. Strategies that have saved populations in the short term and/or enabled recovery include captive breeding, translocation into disease refugia, translocation from resistant populations, disease-free exclosures, and preservation of disease refuges with connectivity to previous habitat, while antifungal treatments have reduced mortality rates in the wild. Increasing host resistance is the goal of many strategies under development, including vaccination and targeted genetic interventions. Pathogen-directed strategies may be more challenging but would have broad applicability. While the search for the silver bullet solution continues, we should value targeted local interventions that stop extinction and buy time for evolution of resistance or development of novel solutions. As for most invasive species and infectious diseases, we need to accept that ongoing management is necessary. For species continuing to decline, proactive deployment and assessment of promising interventions are more valid than a hands-off, do-no-harm approach that will likely allow further extinctions.

Estrogen contamination increases vulnerability of amphibians to the deadly chytrid fungus.

Aquatic contaminants and infectious diseases are among the major drivers of global amphibian declines. However, the interaction of these factors is poorly explored and could better explain the amphibian crisis. We exposed males and females of the Brazilian Cururu Toad, Rhinella icterica, to an environmentally relevant concentration of the estrogen 17-alpha-ethinylestradiol (an emerging contaminant) and to the chytrid infection (Batrachochytrium dendrobatidis), in their combined and isolated forms, and the ecotoxicity was determined by multiple biomarkers: cutaneous, hematological, cardiac, hepatic, and gonadal analysis. Our results showed that Cururu toads had many physiological alterations in response to the chytrid infection, including the appearance of cutaneous Langerhans's cells, increased blood leukocytes, increased heart contraction force and tachycardia, increased hepatic melanomacrophage cells, which in turn led to gonadal atrophy. The estrogen, in turn, increased the susceptibility of the toads to the chytrid infection (higher Bd loads) and maximized the deleterious effects of the pathogen: reducing leukocytes, decreasing the contraction force, and causing greater tachycardia, increasing hepatic melanomacrophage cells, and leading to greater gonadal atrophy, which were more extreme in females. The exposure to estrogen also revealed important toxicodynamic pathways of this toxicant, as shown by the immunosuppression of exposed animals, and the induction of the first stages of feminization in males, which corroborates that the synthetic estrogen acts as an endocrine disruptor. Such an intricate relationship is unprecedented and reinforces the importance of studying the serious consequences that multiple environmental stressors can cause to aquatic populations.

Effects of ophidiomycosis on movement, survival, and reproduction of eastern foxsnakes (Pantherophis vulpinus).

Ophidiomycosis (snake fungal disease) is caused by the fungal pathogen Ophidiomyces ophidiicola, which causes dermal lesions, occasional systemic infections, and in some cases, mortality. To better understand potential conservation implications of ophidiomycosis (i.e., population-level effects), we investigated its impacts on individual fitness in a population of endangered eastern foxsnakes (Pantherophis vulpinus). We tracked 38 foxsnakes over 6 years and quantified body condition, movement patterns, oviposition rates, and survival. Body condition, distance travelled, and oviposition rates were similar between snakes with and without ophidiomycosis. Interestingly, snakes that tested positive for the pathogen travelled farther, suggesting that movement through a greater diversity of habitats increases risk of exposure. Ophidiomycosis did not negatively affect survival, and most apparently infected snakes persisted in a manner comparable to snakes without ophidiomycosis. Only one mortality was directly attributed to ophidiomycosis, although infected snakes were overrepresented in a sample of snakes killed by predators. Overall, our results suggest that ophidiomycosis may have sublethal effects on eastern foxsnakes, but do not suggest direct effects on survival, ovipositioning, or viability of the study population.

A diverse spectrum of mycoses histologically diagnosed in Ghana: Insights from a 10-year retrospective study.

In Ghana, most laboratory diagnoses of severe mycoses are based on histopathology findings due to inadequate availability of serology, culture, and molecular tests. The aim of this study was to evaluate the spectrum of mycoses diagnosed in Ghana. We retrospectively reviewed reports from 2012 to 2021 from three major pathology laboratories in Ghana to identify reports indicating the presence of fungal elements and diagnosis of a mycosis, then extracted demographic, clinical history, site of infection, stain(s), used and diagnosed mycosis details. Over the 10-year period, 107 cases were found. No apparent increasing and decreasing trend in the number of cases per year or in a period was observed. The age range of affected patients was from 4 to 86 years. Special stains for fungi were only used in 22 of 107 (20.6%) of cases. The most frequently affected site was the sino-nasal area (34%). Mycosis type was determined for 58 (54.2%) cases, comprising aspergillosis (21), candidiasis (14), dermatophytosis (6), mucormycosis (3), two cases each of chromoblastomycosis, histoplasmosis, eumycetoma, entomophthoromycosis, sporotrichosis, and Malassezia infection and a single case each of cryptococcosis and deep onychomycosis. Of the 53 (49.5%) cases with presumptive diagnosis data, only seven (13.2%) had a pre-biopsy suspicion of mycosis. There is a wide spectrum of mycoses in Ghana, including endemic mycoses not previously reported. Improving the use of special fungal stains could increase yield and mycoses identification. Laboratory diagnostic capacity needs enhancement to complement histopathology investigations with serology, culture, and molecular methods.

In Ghana, diagnosis of mycoses is mainly based on histopathology findings. To appreciate the varied mycoses diagnosed, we reviewed the reports of major laboratories from 2012 to 2021 and found 107 cases including endemic, rare, and previously unreported cases with fungal stains unusually used.

FIRST RECORD OF BATRACHOCHYTRIUM DENDROBATIDIS IN THE NORTHERN NETHERLANDS.

Batrachochytrium dendrobatidis (Bd) infects amphibians and has been linked to the decline of hundreds of anuran amphibians all over the world. In the province of Groningen in the Netherlands, this fungal pathogen was not detected before this study. To determine whether Groningen was Bd-free, we surveyed 12 locations in this province in 2020 and 2021. Samples were then used to quantify the presence of Bd with a qPCR assay. In total, 2 out of 110 (∼0.02%) collected in 2020 and 11 out of 249 samples collected in 2021 tested positive for Bd. Infected amphibians were found in 4 out of the 12 sites, and the prevalence of Bd was estimated at 4% for both years combined. Our study provides the first record of Bd in Groningen, and we hypothesize that Bd is present throughout the Netherlands in regions currently considered "Bd-free." Furthermore, we warn scientists and policymakers to be apprehensive when calling a site free from Bd when sampling is limited or not recent.

Isolation and investigation of external reproduction tract mycoflora in healthy male cats.

BACKGROUND: Various infectious agents can infect the male reproductive system. OBJECTIVES: The aims of this study were to provide current data on fungal and yeast flora of the external organs of reproductive system of male short hair cats including penis and prepuce. METHODS: In total 28 samples were taken from external genital system of male stray cats using sterilised cotton swabs. Samples were taken based on the absence of any reproductive complications using physical examinations. The samples were transferred to sterilised Stuart transport media and were then incubated in the Sabouraud dextrose agar with chloramphenicol at 32°C for 48 h. The identification of fungi and yeasts was confirmed by germ tube formation test, CHROM agar, urease testing and Corn meal agar medium with Tween 80. RESULTS: Fungal agents were isolated from 7 (25%) out of 28 male stray cats. Fungal isolates were obtained from the penis and prepuce of 4 (36%) and 7 (100%) male cats, respectively. The most commonly recovered species samples were Candida krusei (3.75%) and Penicillum spp. (6.86%) from the penis and prepuce of the cats, respectively. The external organs of male reproduction of cats were infected with 2-4 different fungal agents. Only 5 (45%) cats were infected with one fungus; however, in 6 (55%) cats, mixed fungal infections were isolated. Cats 3-4 years old had the highest fungal contamination in the prepuce region (4/7), while the penis at this age had the least contamination (1/4). CONCLUSIONS: It is concluded that the external reproduction organs of male cats could be infected by different fungal agents.

Skin microbiome disturbance linked to drought-associated amphibian disease.

The onset of global climate change has led to abnormal rainfall patterns, disrupting associations between wildlife and their symbiotic microorganisms. We monitored a population of pumpkin toadlets and their skin bacteria in the Brazilian Atlantic Forest during a drought. Given the recognized ability of some amphibian skin bacteria to inhibit the widespread fungal pathogen Batrachochytrium dendrobatidis (Bd), we investigated links between skin microbiome health, susceptibility to Bd and host mortality during a die-off event. We found that rainfall deficit was an indirect predictor of Bd loads through microbiome disruption, while its direct effect on Bd was weak. The microbiome was characterized by fewer putative Bd-inhibitory bacteria following the drought, which points to a one-month lagged effect of drought on the microbiome that may have increased toadlet susceptibility to Bd. Our study underscores the capacity of rainfall variability to disturb complex host-microbiome interactions and alter wildlife disease dynamics.

Is milbemycin a game changer against antifungal drug-resistant mycoses?

Milbemycin oximes are macrocyclic lactones that have a broad spectrum of activity against nematode infection in animals. They are known to block drug efflux, which increases the susceptibility of fungi to azoles. We investigated the effects of milbemycin on the azole susceptibility of fungi (Aspergillus fumigatus, Candida albicans, C. auris, Cryptococcus neoformans, and Trichophyton rubrum). To screen for changes in azole susceptibility, fungal growth was tested on a culture medium containing 1 µg/ml milbemycin. The results showed that milbemycin increased the azole susceptibility of azole-resistant strains of C. albicans, C. auris, C. neoformans, and T. rubrum. Thus, milbemycin might be useful against antifungal drug-resistant strains.

Milbemycin blocks drug efflux and increases the azole susceptibility of azole-resistant strains of Candida albicans, C. auris, Cryptococcus neoformans, and Trichophyton rubrum. This drug is expected to be a game changer against antifungal drug-resistant infections.