Swimmer’s itch: etiology, impact, and risk factors in Europe

This review summarizes current knowledge about the occurrence and distribution of swimmer’s itch, with a focus on Europe. Although recent publications have reviewed the biology and systematics of bird schistosomes and their complex host–parasite interactions, the underlying ecological factors that create favorable conditions for the parasites and the way humans interact with infested water bodies require further attention. Relevant studies from the past decade were analyzed to reveal an almost complete set of ecological factors as a prerequisite for establishing the life cycle of bird schistosomes. Based on both records of the occurrence of the parasite infective agents, and epidemiological studies that investigate outbreaks of swimmer’s itch, this review concentrates on the risk factors for humans engaged in recreational water activitie

Morphological and molecular data for larval stages of four species of Petasiger Dietz, 1909 (Digenea: Echinostomatidae) with an updated key to the known cercariae from the Palaearctic

Large-tailed echinostomatid cercariae of the genus Petasiger Dietz, 1909 (Digenea: Echinostomatidae) from the planorbid snails Gyraulus albus (Mu¨ ller) and Planorbis planorbis (L.) collected in Germany and the Czech Republic and metacercariae from Gasterosteus aculeatus L. (Gasterosteiformes: Gasterosteidae) collected in Canada are characterised morphologically and molecularly. The rediae, cercariae and metacercariae are described in detail and compared with the existing data on the larval stages of Petasiger spp. Comparative molecular analyses using 28S rDNA and nad1 mitochondrial sequences supported the distinct status of four species of Petasiger. Molecular and morphological evidence for their distinction and an updated key to the known largetailed cercariae of Petasiger from the Palaearctic are provided

Taxa-specific activity loss and mortality patterns in freshwater trematode cercariae under subarctic conditions

Cercarial activity and survival are crucial traits for the transmission of trematodes. Temperature is particularly important, as faster depletion of limited cercarial energy reserves occurs at high temperatures. Seasonal climate conditions in high latitude regions may be challenging to complete trematode life cycle during the 6-month ice-free period, but temperature effects on the activity and survival of freshwater cercariae have not been previously identified. After experimentally simulating natural subarctic conditions during warmer and colder months (13 and 6°C), a statistical approach identifying changes in the tendency of cercarial activity loss and mortality data was used to detect differences in three trematode genera, represented by four taxa (Diplostomum spp., Apatemon spp., small- and large-sized Plagiorchis spp.). A strong temperature-dependent response was identified in both activity loss and mortality in all taxa, with Diplostomum spp. cercariae showing the most gradual changes compared to other taxa. Furthermore, whilst activity loss and mortality dynamics could not be divided into ‘fish- vs invertebrate-infecting cercariae’ groups, the detected taxa-specific responses in relation to life-history traits indicate the swimming behaviour of cercariae and energy allocation among larvae individuals as the main drivers. Cercariae exploit the short transmission window that allows a stable continuance of trematodes’ life cycles in high-latitude freshwater ecosystems.</p

Electrochemistry of ring-substituted 1-hydroxynaphthalene-2-carboxanilides: Relation to structure and biological activity

Twenty-two novel antimycobacterial agents, 1-hydroxynaphthalene-2-carboxanilides, were studied by cyclic voltammetry on a glassy carbon electrode in a phosphate buffer pH 7.2 – dimethyl sulfoxide (DMSO) mixed medium (9:1; v/v). All compounds exhibited similar voltammetric behavior with one irreversible anodic signal in the range 100–300 mV corresponding to the oxidation of hydroxyl group on the naphthalene moiety. A shift of the oxidation potential was caused solely by electron donating or withdrawing effects of substituents and their position on the benzene moiety. Mechanism of oxidation in the studied medium was briefly outlined. Values of oxidation potentials exhibited very good linear correlation with calculated Hammett σ substituent constants. For all active compounds, a relationship between oxidation potentials and MIC or IC50 values obtained from in vitro screening was investigated in detail. Primary in vitro screening of synthesized compounds was previously performed against three species of Mycobacterium pathogens. Additionally, their activity related to the inhibition of photosynthetic electron transport (PET) in spinach chloroplasts was tested in previous publications. In vitro screening against Mycobacterium tuberculosis was performed here for the first time with 1-hydroxy-N-(3-trifluoromethylphenyl)naphthalene-2-carboxamide being the most effective (MIC = 11.7 μmol L−1). Furthermore, several other compounds showed higher antimycobacterial activity than the standard isoniazid. Relation of biological activities and oxidation potentials was successfully found in some cases; however, final correlations must also be considered with other physical and chemical factors contributing to the biological activity. Relation of structure, biological activity and electrochemical potential was also studied by cyclic voltammetry in cathodic area for three compounds containing reducible nitro moiety. © 2019 Elsevier Lt