ORCID Profile
0000-0001-9717-4338
Current Organisations
University of Veterinary Medicine Vienna
,
University of Vienna
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Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.MEEGID.2013.11.009
Abstract: Johne's disease, or paratuberculosis, is a chronic fatal ruminant gastroenteritis caused by Mycobacterium avium subspecies paratuberculosis (MAP) whose foodborne zoonotic potential and association with Crohn's disease are still under debate. The disease is widespread but its epidemiology and epizootiology remains elusive. Wildlife is suspected to play a major role. After a surge in MAP seroprevalence in Austrian cattle, paratuberculosis was declared a notifiable disease in Austria in 2006. At the same time a rise in MAP cases in wild ruminant populations in the Austrian province of Styria was reported. All five autochthonous ruminants were affected. Genetic analysis of isolates, yielded numerous genotypes (>15) and several multiple strain infections (15%) across host species. Identical MIRU-VNTR profiles were identified in different species and s ling locations. On the other hand varying MIRU-VNTR profiles were revealed at the same location and in conspecifics. Our data, taken together with earlier epidemiological studies on MAP and other mycobacteria, raised concerns about the organisms' ecology. Constraints regarding in vitro culture of this highly fastidious organism potentially bias our current understanding of its epidemiology. We suggest that MAP infections could be polyclonal and question the informative value of genotyping a single MAP colony derived from a single specimen for epidemiological analysis of MAP.
Publisher: Springer Science and Business Media LLC
Date: 11-2018
Publisher: Public Library of Science (PLoS)
Date: 04-04-2014
Publisher: Springer Science and Business Media LLC
Date: 24-05-2023
DOI: 10.1186/S12983-023-00498-9
Abstract: Torpor is an energy saving strategy achieved by substantial reductions of metabolic rate and body temperature that enables animals to survive periods of low resource availability. During hibernation (multiday torpor), the frequency of periodic rewarming—characterised by high levels of oxidative stress—is associated with shortening of telomeres, a marker of somatic maintenance. In this study, we determined the impact of ambient temperature on feeding behaviour and telomere dynamics in hibernating garden dormice ( Eliomys quercinus ) over winter. This obligate hibernator prepares for hibernation by accumulating fat stores but can also feed during hibernation. Food intake, torpor pattern, changes in telomere length, and body mass change were assessed in animals housed at experimentally controlled temperatures of either 14 °C (i.e., a mild winter) or 3 °C (i.e., a cold winter) over 6 months. When hibernating at 14 °C, dormice experienced 1.7-fold more frequent and 2.4-fold longer inter-bout euthermia, and spent significantly less time torpid, compared to animals hibernating at 3 °C. Higher food intake enabled in iduals to compensate for increased energetic costs when hibernating at milder temperatures (14 °C vs. 3 °C), to buffer body mass loss and thus increase winter survival. Interestingly, we observed a significant increase of telomere length over the entire hibernation period, irrespective of temperature treatment. We conclude that higher temperatures during winter, if associated with sufficient food availability, can have a positive effect on the in idual’s energy balance and somatic maintenance. These results suggest that winter food availability might be a crucial determinant for the survival of the garden dormouse in the context of ever-increasing environmental temperatures.
Publisher: Springer Science and Business Media LLC
Date: 21-12-2020
DOI: 10.1007/S11686-020-00325-9
Abstract: Alveolar echinococcosis is a severe helminthic disease in humans caused by larvae of the fox tapeworm Echinococcus multilocularis. Austria is considered an endemic area with hotspots having up to 45% prevalence (Bagó et al. in Proceedings of the Zoo and Wildlife Health Conference 2019, Berlin, p. 91, 2019). At our facility, we have registered a notifiable increase of animals submitted for the diagnosis of E. multilocularis since 2016. Therefore, we investigated high throughput diagnostic methods to provide rapid and reliable results in comparison with our current method. We have developed and compared a novel method of detection using droplet digital PCR (ddPCR) combined with previous target specific extraction according to Maas et al. (Vet Parasitol 230:20–24, 2016), with our current macroscopic method “Shaking in a Vessel Technique” (SVT) by Duscher et al. (Parasitol Res 95(1):40–42, 2005). We investigated 77 wild canids (72 red foxes, 5 golden jackals) using both methods. The data were analyzed using a non-Bayesian approach, applying bootstrapping to create confidentiality intervals. Sensitivity for droplet digital PCR was 90.51% with the 95% credibility interval ranging from 82.50 to 96.92%, whereas mean sensitivity for SVT was 92.04% with a 95% credibility interval ranging from 84.75% to 98.36%. Additionally, a non-linear regression similar to R 2 could be pointed out between the counted worms and the results gathered from ddPCR. Magnetic capture extraction followed by ddPCR shows strong potential as a high throughput method for diagnosing E. multilocularis prevalence in erse canid populations as well as infection intensities of in idual animals, giving valuable epidemiological insights of the distribution amongst wild canids as an alternative to conventional qPCR or macroscopic methods.
Publisher: Wiley
Date: 30-10-2021
DOI: 10.1111/MEC.16233
Abstract: Increasing evidence at the cellular level is helping to provide proximate explanations for the balance between investment in growth, reproduction and somatic maintenance in wild populations. Studies of telomere dynamics have informed researchers about the loss and gain of telomere length both on a seasonal scale and across the lifespan of in iduals. In addition, telomere length and telomere rate of loss seems to have evolved differently among taxonomic groups, and relate differently to organismal ersity of lifespan. So far, the mechanisms behind telomere maintenance remain elusive, although many studies have inferred a role for telomerase, an enzyme/RNA complex known to induce telomere elongation from laboratory studies. Exciting further work is also emerging that suggests telomerase (and/or its in idual component parts) has a role in fitness that goes beyond the maintenance of telomere length. Here, we review the literature on telomerase biology and examine the evidence from ecological studies for the timing and extent of telomerase activation in relation to life history events associated with telomere maintenance. We suggest that the underlying mechanism is more complicated than originally anticipated, possibly involves several complimentary pathways, and is probably associated with high energetic costs. Potential pathways for future research are numerous and we outline what we see as the most promising prospects to expand our understanding of in idual differences in immunity or reproduction efficiency.
Publisher: Wiley
Date: 06-11-2021
DOI: 10.1111/JEB.13954
Abstract: Life‐history theory predicts a trade‐off between growth rates and lifespan, which is reflected by telomere length, a biomarker of somatic state. We investigated the correlation between telomere length and early‐life growth of wild boar piglets, Sus scrofa , kept under semi‐natural conditions with high food availability to examine our hypothesis that increased pre‐ and postnatal growth will lead to telomere length attrition, but that a high supply of nutrient may provide the possibility to compensate telomere loss via telomere repair mechanisms. As predicted, our data showed a clear negative correlation between birth body mass and initial telomere length: heavier neonates had shorter telomeres at birth, and we did not find an influence of the mother on initial telomere length. Body mass at birth correlated with body mass later in life and postnatal growth rate did not affect telomere length. We observed an increase in telomere length during postnatal development, suggesting that high food availability allowed piglets to invest into both, growth and telomere restoration. The increase in telomere length over the duration of the study was not accompanied by telomerase activity thus, telomere elongation was caused either by alternative mechanisms or by short pulses of telomerase activity that we missed. Taken together, this study suggests a trade‐off between investment into growth and telomere maintenance even before birth and the possibility to compensate telomere attrition during growth under high amounts of available energy.
Publisher: The Company of Biologists
Date: 15-08-2016
DOI: 10.1242/JEB.140871
Abstract: We studied the impact of hibernation and food supply on relative telomere length (RTL), an indicator for aging and somatic maintenance, in free-living edible dormice. Small hibernators such as dormice have ∼50% higher maximum longevity than non-hibernators. Increased longevity could theoretically be due to prolonged torpor directly slowing cellular damage and RTL shortening. However, although mitosis is arrested in mammals at low body temperatures, recent evidence points to accelerated RTL shortening during periodic re-warming (arousal) from torpor. Therefore, we hypothesized that these arousals during hibernation should have a negative effect on RTL. Here, we show that RTL was shortened in all animals over the course of ∼1 year, during which dormice hibernated for 7.5–11.4 months. The rate of periodic arousals, rather than the time spent euthermic during the hibernation season, was the best predictor of RTL shortening. This finding points to negative effects on RTL of the transition from low torpor to high euthermic body temperature and metabolic rate during arousals, possibly because of increased oxidative stress. The animals were, however, able to elongate their telomeres during the active season, when food availability was increased by supplemental feeding in a year of low natural food abundance. We conclude that in addition to their energetic costs, periodic arousals also lead to accelerated cellular damage in terms of RTL shortening. Although dormice are able to counteract and even over-compensate for the negative effects of hibernation, restoration of RTL appears to be energetically costly.
No related grants have been discovered for Franz Hoelzl.