Most cited article - PubMed ID 26821755
White-nose syndrome without borders: Pseudogymnoascus destructans infection tolerated in Europe and Palearctic Asia but not in North America
Recent research on chiropteran parasites suggests a high prevalence and diversity, and extensive spatial distribution of filarial species; however, ecological and phylogenetic studies are still in their infancy. We sampled blood from 78 bat specimens, collected 1181 ectoparasites at summer colonies in Armenia and Georgia, and used nested-PCR targeting the cytochrome c oxidase subunit 1 (cox1) gene to detect and genotype filarial parasites. The overall prevalence of filarial DNA was 17.9% in blood samples from Myotis blythii, Myotis emarginatus, Miniopterus schreibersii, and Rhinolophus ferrumequinum, and 8.5% in ectoparasites, including two mite species (Eyndhovenia euryalis and Spinturnix myoti) and two bat flies (Nycteribia kolenatii and Penicillidia dufouri). The prevalence of microfilarial infection was significantly higher in mite samples (13.8%) than in bat fly samples (4.1%). Bats with ectoparasites positive for filarial DNA had a significantly higher total number of ectoparasites. Phylogenetic analysis placed the 18 sequences obtained into different closely related clades of onchocercid nematodes, with four different species recorded: two belonging to the genus Litomosa and two to a newly observed genus of the family Onchocercidae. Additionally, two new species of these parasites, one Litomosa sp. and one Onchocercid sp., were genetically recognised. As predicted, the diversity of filarial parasites reflects the diversity of bat hosts in the Caucasus. Extending the sampling effort to more Caucasian bat species will likely reveal previously unknown filarial species. Non-lethal and non-invasive sampling of blood and ectoparasites for molecular screening proved effective for gaining insights into parasite diversity and phylogenetic relationships of bat-infecting filarial nematodes.
- Keywords
- Bat blood parasites, Bat flies, Bat mites, Filarioidea, Nematodes, Onchocercidae, Vector-borne parasites, cox1,
- Publication type
- Journal Article MeSH
Disease can act as a driving force in shaping genetic makeup across populations, even species, if the impacts influence a particularly sensitive part of their life cycles. White-nose disease is caused by a fungal pathogen infecting bats during hibernation. The mycosis has caused massive population declines of susceptible species in North America, particularly in the genus Myotis. However, Myotis bats appear to tolerate infection in Eurasia, where the fungal pathogen has co-evolved with its bat hosts for an extended period of time. Therefore, with susceptible and tolerant populations, the fungal disease provides a unique opportunity to tease apart factors contributing to tolerance at a genomic level to and gain an understanding of the evolution of non-harmful in host-parasite interactions. To investigate if the fungal disease has caused adaptation on a genomic level in Eurasian bat species, we adopted both whole-genome sequencing approaches and a literature search to compile a set of 300 genes from which to investigate signals of positive selection in genomes of 11 Eurasian bats at the codon-level. Our results indicate significant positive selection in 38 genes, many of which have a marked role in responses to infection. Our findings suggest that white-nose syndrome may have applied a significant selective pressure on Eurasian Myotis-bats in the past, which can contribute their survival in co-existence with the pathogen. Our findings provide an insight on the selective pressure pathogens afflict on their hosts using methodology that can be adapted to other host-pathogen study systems.
- Keywords
- Adaptation, Bats, Disease, Fungal pathogen, Positive selection, Tolerance,
- MeSH
- Chiroptera * microbiology genetics MeSH
- Genome MeSH
- Genomics methods MeSH
- Host-Pathogen Interactions genetics MeSH
- Evolution, Molecular MeSH
- Mycoses microbiology veterinary MeSH
- Whole Genome Sequencing MeSH
- Selection, Genetic * MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
INTRODUCTION: Serological tests can be used to test whether an animal has been exposed to an infectious agent, and whether its immune system has recognized and produced antibodies against it. Paired samples taken several weeks apart then document an ongoing infection and/or seroconversion. METHODS: In the absence of a commercial kit, we developed an indirect enzyme-linked immunosorbent assay (ELISA) to detect the fungus-specific antibodies for Pseudogymnoascus destructans, the agent of white-nose syndrome in bats. RESULTS AND DISCUSSION: Samples collected from European Myotis myotis (n=35) and Asian Myotis dasycneme (n=11) in their hibernacula at the end of the hibernation period displayed 100% seroprevalence of antibodies against P. destructans, demonstrating a high rate of exposure. Our results showed that the higher the titre of antibodies against P. destructans, the lower the infection intensity, suggesting that a degree of protection is provided by this arm of adaptive immunity in Palearctic bats. Moreover, P. destructans infection appears to be a seasonally self-limiting disease of Palearctic bats showing seroconversion as the WNS skin lesions heal in the early post-hibernation period.
- Keywords
- Myotis bat species, adaptive antifungal immunity, antibody prevalence, disease severity, emerging wildlife infection, indirect ELISA,
- MeSH
- Ascomycota MeSH
- Chiroptera * MeSH
- Skin Diseases * MeSH
- Mycoses * epidemiology veterinary MeSH
- Seroepidemiologic Studies MeSH
- Syndrome MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
BACKGROUND: North American bat populations have suffered severe declines over the last decade due to the Pseudogymnoascus destructans fungus infection. The skin disease associated with this causative agent, known as white-nose syndrome (WNS), is specific to bats hibernating in temperate regions. As cultured fungal isolates are required for epidemiological and phylogeographical studies, the purpose of the present work was to compare the efficacy and reliability of different culture approaches based on either skin swabs or wing membrane tissue biopsies for obtaining viable fungal isolates of P. destructans. RESULTS: In total, we collected and analysed 69 fungal and 65 bacterial skin swabs and 51 wing membrane tissue biopsies from three bat species in the Czech Republic, Poland and the Republic of Armenia. From these, we obtained 12 viable P. destructans culture isolates. CONCLUSIONS: Our results indicated that the efficacy of cultures based on wing membrane biopsies were significantly higher. Cultivable samples tended to be based on collections from bats with lower body surface temperature and higher counts of UV-visualised lesions. While cultures based on both skin swabs and wing membrane tissue biopsies can be utilised for monitoring and surveillance of P. destructans in bat populations, wing membrane biopsies guided by UV light for skin lesions proved higher efficacy. Interactions between bacteria on the host's skin also appear to play an important role.
- Keywords
- Bats, Fungal culture, Fungal infection, Pseudogymnoascus destructans skin microbiota, UV lesions,
- MeSH
- Chiroptera * microbiology MeSH
- Hibernation * MeSH
- Skin Diseases * veterinary MeSH
- Culture Media MeSH
- Skin pathology MeSH
- Reproducibility of Results MeSH
- Syndrome MeSH
- Ultraviolet Rays MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Names of Substances
- Culture Media MeSH
Fungi are an understudied resource possessing huge potential for developing products that can greatly improve human well-being. In the current paper, we highlight some important discoveries and developments in applied mycology and interdisciplinary Life Science research. These examples concern recently introduced drugs for the treatment of infections and neurological diseases; application of -OMICS techniques and genetic tools in medical mycology and the regulation of mycotoxin production; as well as some highlights of mushroom cultivaton in Asia. Examples for new diagnostic tools in medical mycology and the exploitation of new candidates for therapeutic drugs, are also given. In addition, two entries illustrating the latest developments in the use of fungi for biodegradation and fungal biomaterial production are provided. Some other areas where there have been and/or will be significant developments are also included. It is our hope that this paper will help realise the importance of fungi as a potential industrial resource and see the next two decades bring forward many new fungal and fungus-derived products.
- Keywords
- Biomaterial, CRISPR, Drug development, Morel cultivation, Mushroom cultivation, Mycotoxin biosynthesis, Plastic degradation,
- Publication type
- Journal Article MeSH
- Review MeSH
Heterothermy, as a temperature-dependent physiological continuum, may affect host-pathogen interactions through modulation of immune responses. Here, we evaluated proliferation and functional performance of a macrophage cell line established from the greater mouse-eared (Myotis myotis) bat at 8, 17.5, and 37°C to simulate body temperatures during hibernation, daily torpor and euthermia. Macrophages were also frozen to -20°C and then examined for their ability to proliferate in the immediate post-thaw period. We show that bat macrophages can proliferate at lower temperatures, though their growth rate is significantly slower than at 37°C. The cells differed in their shape, size and ability to attach to the plate surface at both lower temperatures, being spheroidal and free in suspension at 8°C and epithelial-like, spindle-shaped and/or spheroidal at 17.5°C. While phagocytosis at temperatures of 8 and 17.5°C amounted to 85.8 and 83.1% of the activity observed at 37°C, respectively, full phagocytic activity was restored within minutes of translocation into a higher temperature. Bat-derived macrophages were also able to withstand temperatures of -20°C in a cryoprotectant-free cultivation medium and, in the immediate post-thaw period, became viable and were able to proliferate. Our in vitro data enhance understanding of macrophage biology.
- Keywords
- Chiroptera (bats), daily torpor, hibernation, in vitro model, macrophage biology, phagocytic activity, temperature-dependent proliferation,
- Publication type
- Journal Article MeSH
BACKGROUND: Palearctic bats host a diversity of lyssaviruses, though not the classical rabies virus (RABV). As surveillance for bat rabies over the Palearctic area covering Central and Eastern Europe and Siberian regions of Russia has been irregular, we lack data on geographic and seasonal patterns of the infection. RESULTS: To address this, we undertook serological testing, using non-lethally sampled blood, on 1027 bats of 25 species in Bulgaria, the Czech Republic, Poland, Russia and Slovenia between 2014 and 2018. The indirect enzyme-linked immunosorbent assay (ELISA) detected rabies virus anti-glycoprotein antibodies in 33 bats, giving an overall seroprevalence of 3.2%. Bat species exceeding the seroconversion threshold included Myotis blythii, Myotis gracilis, Myotis petax, Myotis myotis, Murina hilgendorfi, Rhinolophus ferrumequinum and Vespertilio murinus. While Myotis species (84.8%) and adult females (48.5%) dominated in seropositive bats, juveniles of both sexes showed no difference in seroprevalence. Higher numbers tested positive when sampled during the active season (10.5%), as compared with the hibernation period (0.9%). Bat rabies seroprevalence was significantly higher in natural habitats (4.0%) compared with synanthropic roosts (1.2%). Importantly, in 2018, we recorded 73.1% seroprevalence in a cave containing a M. blythii maternity colony in the Altai Krai of Russia. CONCLUSIONS: Identification of such "hotspots" of non-RABV lyssavirus circulation not only provides important information for public health protection, it can also guide research activities aimed at more in-depth bat rabies studies.
- Keywords
- Chiroptera, Europe, Siberia, blood samples, rabies, seroprevalence,
- MeSH
- Chiroptera virology MeSH
- Ecosystem MeSH
- Rhabdoviridae Infections epidemiology MeSH
- Caves MeSH
- Lyssavirus isolation & purification MeSH
- Antibodies, Viral blood MeSH
- Seasons MeSH
- Seroepidemiologic Studies MeSH
- Animals MeSH
- Check Tag
- Male MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Europe epidemiology MeSH
- Russia epidemiology MeSH
- Names of Substances
- Antibodies, Viral MeSH
Understanding how context (e.g., host species, environmental conditions) drives disease susceptibility is an essential goal of disease ecology. We hypothesized that in bat white-nose syndrome (WNS), species-specific host-pathogen interactions may partly explain varying disease outcomes among host species. We characterized bat and pathogen transcriptomes in paired samples of lesion-positive and lesion-negative wing tissue from bats infected with Pseudogymnoascus destructans in three parallel experiments. The first two experiments analyzed samples collected from the susceptible Nearctic Myotis lucifugus and the less-susceptible Nearctic Eptesicus fuscus, following experimental infection and hibernation in captivity under controlled conditions. The third experiment applied the same analyses to paired samples from infected, free-ranging Myotis myotis, a less susceptible, Palearctic species, following natural infection and hibernation (n = 8 sample pairs/species). Gene expression by P. destructans was similar among the three host species despite varying environmental conditions among the three experiments and was similar within each host species between saprophytic contexts (superficial growth on wings) and pathogenic contexts (growth in lesions on the same wings). In contrast, we observed qualitative variation in host response: M. lucifugus and M. myotis exhibited systemic responses to infection, while E. fuscus up-regulated a remarkably localized response. Our results suggest potential phylogenetic determinants of response to WNS and can inform further studies of context-dependent host-pathogen interactions.
- Keywords
- Eptesicus fuscus, Myotis lucifugus, Myotis myotis, Pseudogymnoascus destructans, Disease ecology, emerging infectious diseases, host–pathogen interactions, susceptibility, virulence,
- MeSH
- Ascomycota genetics pathogenicity MeSH
- Chiroptera classification microbiology MeSH
- Dermatomycoses microbiology veterinary MeSH
- Species Specificity MeSH
- Phylogeny MeSH
- Host-Pathogen Interactions genetics MeSH
- Wings, Animal microbiology pathology MeSH
- Nose microbiology pathology MeSH
- Gene Expression Profiling * MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The genus Pseudogymnoascus encompasses soil psychrophilic fungi living also in caves. Some are opportunistic pathogens; nevertheless, they do not cause outbreaks. Pseudogymnoascus destructans is the causative agent of the white-nose syndrome, which is decimating cave-hibernating bats. We used comparative eco-physiology to contrast the enzymatic potential and conidial resilience of P. destructans with that of phylogenetically diverse cave fungi, including Pseudogymnoascus spp., dermatophytes and outdoor saprotrophs. Enzymatic potential was assessed by Biolog MicroArray and by growth on labelled substrates and conidial viability was detected by flow cytometry. Pseudogymnoascus destructans was specific by extensive losses of metabolic variability and by ability of lipid degradation. We suppose that lipases are important enzymes allowing fungal hyphae to digest and invade the skin. Pseudogymnoascus destructans prefers nitrogenous substrates occurring in bat skin and lipids. Additionally, P. destructans alkalizes growth medium, which points to another possible virulence mechanism. Temperature above 30 °C substantially decreases conidial viability of cave fungi including P. destructans. Nevertheless, survival of P. destructans conidia prolongs by the temperature regime simulating beginning of the flight season, what suggests that conidia could persist on the body surface of bats and contribute to disease spreading during bats active season.
- MeSH
- Ascomycota enzymology metabolism physiology MeSH
- Chiroptera microbiology physiology MeSH
- Phylogeny MeSH
- Caves MeSH
- Lipase MeSH
- Mycoses physiopathology MeSH
- Nose microbiology MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- Czech Republic MeSH
- Names of Substances
- Lipase MeSH
BACKGROUND: Behaviour during hibernation contributes to energy conservation in winter. Hibernating bats select roosts with respect to physiological and environmental stressors, available local microclimate and species-specific requirements. RESULTS: We found that, in the period between 1977 and 2018, hibernating Myotis myotis and Rhinolophus hipposideros bats showed exponential population growth. The growth rates, corrected for local winter seasonal severity and winter duration, were equal to 10 and 13%, respectively. While R. hipposideros only utilised the thermally stable and, at survey time, warmer corridors in the hibernaculum, an increasing proportion of M. myotis roosted in the thermally stable corridors as their abundance increased. About 14% of all hibernating M. myotis displayed solitary roosting, irrespective of other covariates. Those bats that clustered together formed progressively larger clusters with increasing abundance, particularly in cold corridors. We found no statistically significant relationship for clustering behaviour or cluster size with winter severity or winter duration. CONCLUSIONS: Abundance of hibernating bats is increasing in Central Europe. As the number of M. myotis bats increases, thermally unstable corridors become saturated with large clusters and the animals begin to roost deeper underground.
- Keywords
- Chiroptera, Clustering behaviour, Hibernation, Population size, Winter activity,
- Publication type
- Journal Article MeSH