Publications by authors named "David Herczeg"

Exposure to contagious pathogens can result in behavioural changes, which can alter the spread of infectious diseases. Healthy individuals can express generalized social distancing or avoid the sources of infection, while infected individuals can show passive or active self-isolation. Amphibians are globally threatened by contagious diseases, yet their behavioural responses to infections are scarcely known.

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Species with wide-range distributions usually display high genetic variation. This variation can be partly explained by historical lineages that were temporally isolated from each other and are back into secondary reproductive contact, and partly by local adaptations. The smooth newt () is one of the most widely distributed amphibians species across Eurasia and forms a species complex with a partially overlapping distribution and morphology.

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Extreme temperatures during heat waves can induce mass-mortality events, but can also exert sublethal negative effects by compromising life-history traits and derailing sexual development. Ectothermic animals may, however, also benefit from increased temperatures via enhanced physiological performance and the suppression of cold-adapted pathogens. Therefore, it is crucial to address how the intensity and timing of naturally occurring or human-induced heat waves affect life-history traits and sexual development in amphibians, to predict future effects of climate change and to minimize risks arising from the application of elevated temperature in disease mitigation.

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Parasites, including viruses, bacteria, fungi, protists, helminths, and arthropods, are ubiquitous in the animal kingdom. Consequently, hosts are frequently infected with more than one parasite species simultaneously. The assessment of such co-infections is of fundamental importance for disease ecology, but relevant studies involving non-domesticated animals have remained scarce.

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Across the distribution of the Caspian whipsnake (), populations have become increasingly disconnected due to habitat alteration. To understand population dynamics and this widespread but locally endangered snake's adaptive potential, we investigated population structure, admixture, and effective migration patterns. We took a landscape-genomic approach to identify selected genotypes associated with environmental variables relevant to .

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Here, we experimentally studied the site preference of , one of the most pathogenic myxozoan (Cnidaria, Myxozoa) fish parasites, which causes whirling disease in salmonids. Parasite invasion was examined in three fish species with various susceptibility levels: the type host brown trout, the highly susceptible rainbow trout, and the non-susceptible gibel carp, in which parasite spores do not develop. We investigated the first two hours of fish invasion, and measured the site preference of triactinomyxons (TAMs) during attachment and penetration of fish in three body parts (gills, fins, skin).

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Here, we investigated the early development of two closely related myxozoan parasites, the highly pathogenic Myxobolus cerebralis, the causative agent of the whirling disease in salmonids, and Myxobolus pseudodispar, a common, non-pathogenic parasite of cyprinids. The aim of our study was to examine under in vivo laboratory conditions whether fish blood is involved in the intrapiscine development of the two parasite species and investigate if there is dissimilarity between the parasite infection intensity in blood and if it varies in terms of host susceptibility and parasite pathogenicity. Highly susceptible, less susceptible and non-susceptible hosts were involved.

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One of the main obstacles in freshwater aquaculture is the parasitic ciliate Ichthyophthirius multifiliis (Ich), the causative agent of white spot disease. The use of immunostimulants as feed additives may be a promising approach to control Ich infection. In the present study, we tested the prophylactic effect of orally administered β-1,3/1,6-glucan and propolis extract E50 against Ich infection in common carp.

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