BACKGROUND: Cercarial dermatitis (CD), or swimmer's itch, is a water-borne allergic skin reaction caused by the penetration of the larval stages of bird schistosomes (cercariae) into the skin. Members of the genus Trichobilharzia are the primary causative agents of CD worldwide. Due to the increasing number of cases, CD is regarded as a (re)emerging disease. Outbreaks in recreational waters can significantly impact public health and local economies. Environmental monitoring of Trichobilharzia is crucial for outbreak prediction and public health management. However, conventional methods, such as cercarial shedding and snail dissections, are labour-intensive and lack sensitivity. To overcome these limitations, we present a molecular toolkit that combines loop-mediated isothermal amplification (LAMP), quantitative polymerase chain reaction (qPCR), and multiplex PCR for rapid, sensitive, and accurate detection and identification of Trichobilharzia spp. from various biological samples. METHODS: Tricho-LAMP and Tricho-qPCR were designed and optimised for Trichobilharzia DNA detection. A multiplex PCR assay was also developed and optimised to identify the three main species causing CD in Europe (Trichobilharzia franki, T. szidati, and T. regenti). RESULTS: Tricho-LAMP specifically detected T. regenti and T. franki at 10-3 ng, and T. szidati at 10-2 ng per reaction with genomic DNA. Using gBlocks synthetic DNA, Tricho-LAMP achieved 100% amplification at 10,000 copies and 85% amplification at 1000 copies, with decreasing success at lower concentrations. Tricho-qPCR showed the highest sensitivity, detecting all species down to 10-4 ng per reaction and showing a limit of detection at 10 copies of synthetic DNA in the reaction. Multiplex PCR allowed reliable species differentiation via gel electrophoresis of the PCR products, but the assay had the lowest sensitivity. CONCLUSIONS: We provide a molecular toolkit consisting of LAMP, qPCR, and multiplex PCR. By exhibiting high sensitivity, Tricho-LAMP and Tricho-qPCR assays are potentially suitable for environmental DNA (eDNA)-based environmental monitoring of bird schistosomes, by both researchers and public health authorities. Multiplex PCR can be used for species determination without the need for further sequencing.

• Keywords
• Trichobilharzia, Bird schistosomes, Cercarial dermatitis, Detection, LAMP, Monitoring, Multiplex PCR, qPCR,
• MeSH
• Molecular Diagnostic Techniques * methods   MeSH
• DNA, Helminth genetics   MeSH
• Snails parasitology   MeSH
• Trematode Infections * diagnosis   parasitology   veterinary   MeSH
• Real-Time Polymerase Chain Reaction * methods   MeSH
• Multiplex Polymerase Chain Reaction * methods   MeSH
• Birds parasitology   MeSH
• Schistosomatidae * genetics   isolation & purification   classification   MeSH
• Sensitivity and Specificity MeSH
• Nucleic Acid Amplification Techniques * methods   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• DNA, Helminth MeSH

Skin uses interdependent cellular networks for barrier integrity and host immunity, but most underlying mechanisms remain obscure. Herein, we demonstrate that the human parasitic helminth Schistosoma mansoni inhibited pruritus evoked by itch-sensing afferents bearing the Mas-related G-protein-coupled receptor A3 (MrgprA3) in mice. MrgprA3 neurons controlled interleukin (IL)-17+ γδ T cell expansion, epidermal hyperplasia and host resistance against S. mansoni through shaping cytokine expression in cutaneous antigen-presenting cells. MrgprA3 neuron activation downregulated IL-33 but induced IL-1β and tumor necrosis factor in macrophages and type 2 conventional dendritic cells partially through the neuropeptide calcitonin gene-related peptide. Macrophages exposed to MrgprA3-derived secretions or bearing cell-intrinsic IL-33 deletion showed increased chromatin accessibility at multiple inflammatory cytokine loci, promoting IL-17/IL-23-dependent changes to the epidermis and anti-helminth resistance. This study reveals a previously unrecognized intercellular communication mechanism wherein itch-inducing MrgprA3 neurons initiate host immunity against skin-invasive parasites by directing cytokine expression patterns in myeloid antigen-presenting cell subsets.

• MeSH
• Dendritic Cells immunology   MeSH
• Interleukin-33 * metabolism   immunology   MeSH
• Skin immunology   parasitology   MeSH
• Humans MeSH
• Macrophages immunology   metabolism   MeSH
• Myeloid Cells immunology   metabolism   MeSH
• Mice, Inbred C57BL MeSH
• Mice, Knockout MeSH
• Mice MeSH
• Neurons immunology   metabolism   MeSH
• Pruritus immunology   MeSH
• Receptors, G-Protein-Coupled * metabolism   immunology   genetics   MeSH
• Schistosoma mansoni * immunology   MeSH
• Schistosomiasis mansoni * immunology   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Il33 protein, mouse MeSH Browser
• Interleukin-33 * MeSH
• Receptors, G-Protein-Coupled * MeSH

Helminth neuroinfections represent serious medical conditions, but the diversity of the host-parasite interplay within the nervous tissue often remains poorly understood, partially due to the lack of laboratory models. Here, we investigated the neuroinvasion of the mouse spinal cord by Trichobilharzia regenti (Schistosomatidae). Active migration of T. regenti schistosomula through the mouse spinal cord induced motor deficits in hindlimbs but did not affect the general locomotion or working memory. Histological examination of the infected spinal cord revealed eosinophilic meningomyelitis with eosinophil-rich infiltrates entrapping the schistosomula. Flow cytometry and transcriptomic analysis of the spinal cord confirmed massive activation of the host immune response. Of note, we recorded striking upregulation of the major histocompatibility complex II pathway and M2-associated markers, such as arginase or chitinase-like 3. Arginase also dominated the proteins found in the microdissected tissue from the close vicinity of the migrating schistosomula, which unselectively fed on the host nervous tissue. Next, we evaluated the pathological sequelae of T. regenti neuroinvasion. While no demyelination or blood-brain barrier alterations were noticed, our transcriptomic data revealed a remarkable disruption of neurophysiological functions not yet recorded in helminth neuroinfections. We also detected DNA fragmentation at the host-schistosomulum interface, but schistosomula antigens did not affect the viability of neurons and glial cells in vitro. Collectively, altered locomotion, significant disruption of neurophysiological functions, and strong M2 polarization were the most prominent features of T. regenti neuroinvasion, making it a promising candidate for further neuroinfection research. Indeed, understanding the diversity of pathogen-related neuroinflammatory processes is a prerequisite for developing better protective measures, treatment strategies, and diagnostic tools.

• MeSH
• Arginase metabolism   MeSH
• Biomarkers metabolism   MeSH
• Chemokines metabolism   MeSH
• Eosinophils metabolism   MeSH
• Major Histocompatibility Complex MeSH
• Immunity MeSH
• Trematode Infections immunology   metabolism   pathology   MeSH
• Host-Parasite Interactions MeSH
• Spinal Cord parasitology   MeSH
• Disease Models, Animal MeSH
• Mice, Inbred C57BL MeSH
• Mice MeSH
• Neuroglia parasitology   MeSH
• Neurons parasitology   MeSH
• Schistosomatidae immunology   MeSH
• Gene Expression Profiling MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Arginase MeSH
• Biomarkers MeSH
• Chemokines MeSH

BACKGROUND: Avian schistosomes, the causative agents of human cercarial dermatitis (or swimmer's itch), die in mammals but the mechanisms responsible for parasite elimination are unknown. Here we examined the role of reactive nitrogen species, nitric oxide (NO) and peroxynitrite, in the immune response of mice experimentally infected with Trichobilharzia regenti, a model species of avian schistosomes remarkable for its neuropathogenicity. METHODS: Inducible NO synthase (iNOS) was localized by immunohistochemistry in the skin and the spinal cord of mice infected by T. regenti. The impact of iNOS inhibition by aminoguanidine on parasite burden and growth was then evaluated in vivo. The vulnerability of T. regenti schistosomula to NO and peroxynitrite was assessed in vitro by viability assays and electron microscopy. Additionally, the effect of NO on the activity of T. regenti peptidases was tested using a fluorogenic substrate. RESULTS: iNOS was detected around the parasites in the epidermis 8 h post-infection and also in the spinal cord 3 days post-infection (dpi). Inhibition of iNOS resulted in slower parasite growth 3 dpi, but the opposite effect was observed 7 dpi. At the latter time point, moderately increased parasite burden was also noticed in the spinal cord. In vitro, NO did not impair the parasites, but inhibited the activity of T. regenti cathepsins B1.1 and B2, the peptidases essential for parasite migration and digestion. Peroxynitrite severely damaged the surface tegument of the parasites and decreased their viability in vitro, but rather did not participate in parasite clearance in vivo. CONCLUSIONS: Reactive nitrogen species, specifically NO, do not directly kill T. regenti in mice. NO promotes the parasite growth soon after penetration (3 dpi), but prevents it later (7 dpi) when also suspends the parasite migration in the CNS. NO-related disruption of the parasite proteolytic machinery is partly responsible for this effect.

• Keywords
• 3-Nitrotyrosine, Cathepsin B, Nitric oxide, Nitric oxide synthase, Peroxynitrite, Schistosomatidae, Trichobilharzia,
• MeSH
• Central Nervous System parasitology   MeSH
• Guanidines pharmacology   MeSH
• Trematode Infections drug therapy   MeSH
• Skin parasitology   MeSH
• Peroxynitrous Acid pharmacology   MeSH
• Humans MeSH
• Spinal Cord parasitology   MeSH
• Mice MeSH
• Nitric Oxide pharmacology   MeSH
• Peptide Hydrolases drug effects   metabolism   MeSH
• Helminth Proteins drug effects   metabolism   MeSH
• Birds parasitology   MeSH
• Schistosoma drug effects   growth & development   pathogenicity   MeSH
• Schistosomatidae drug effects   growth & development   pathogenicity   MeSH
• Schistosomiasis drug therapy   MeSH
• Nitric Oxide Synthase drug effects   metabolism   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Guanidines MeSH
• Peroxynitrous Acid MeSH
• Nitric Oxide MeSH
• pimagedine MeSH Browser
• Peptide Hydrolases MeSH
• Helminth Proteins MeSH
• Nitric Oxide Synthase MeSH

Human cercarial dermatitis is a parasitic disease that causes an allergic reaction in the skin (swimmer's itch) as a consequence of contact with cercariae of bird schistosomes present in water, mainly of the genus Trichobilharzia Skrjabin et Zakarow, 1920. The main objective of the study was to confirm the presence of the zoonotic disease agent following reports of human infections in recreational water in Slovakia. We identified two species of freshwater snails at Košice Lake, Radix auricularia (Linnaeus, 1758) and Physa acuta (Draparnaud, 1805). Trematode infections were observed only in R. auricularia. Of the 62 snails collected, 11 (17.7%) were infected with 5 different species of larval stages of trematodes. The blood fluke Trichobilharzia franki was found in 2 (3.2%) of the examined snails. The present record provides the first evidence that T. franki from the pulmonate snail R. auricularia represents a source of human cercarial dermatitis in recreational water in Slovakia. Our finding complements the easternmost records of both swimmer's itch and the confirmed occurrence of a bird schistosome in a waterbody in Europe. The present work suggests that the health risks associated with trichobilharziasis need to be further studied by detailed monitoring of the occurrence of the major causative agent of human cercarial dermatitis, T. franki.

• Keywords
• Bird schistosomes, Cercariae, Cercarial dermatitis, Trematodes, Trichobilharzia, Zoonosis,
• MeSH
• Dermatitis epidemiology   parasitology   MeSH
• Disease Outbreaks MeSH
• Snails parasitology   MeSH
• Trematode Infections epidemiology   parasitology   transmission   MeSH
• Lakes parasitology   MeSH
• Humans MeSH
• Skin Diseases, Parasitic parasitology   transmission   MeSH
• Schistosomatidae classification   genetics   isolation & purification   MeSH
• Schistosomiasis epidemiology   parasitology   transmission   MeSH
• Zoonoses epidemiology   parasitology   transmission   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Slovakia epidemiology   MeSH

Cercarial dermatitis (CD) is an allergic skin disease that rises in consequence of infection by invasive stages (cercariae) of trematodes of the family Schistosomatidae. CD has been considered a re-emerging disease, human cases have been reported from all continents, and tourism-threatening outbreaks occur even in frequented recreational areas. Although the symptoms of CD are generally known, the data on immune response in human patients are sporadic and incomprehensive. In the present study, we attempted to correlate the symptoms, personal history, and time course of CD in human patients with differential cell counts, dynamics of selected cytokines, and dynamics and quality of antibody response. By a systematic follow-up, we obtained a uniquely complex dataset from ten persons accidentally and concurrently infected by the same parasite species in the same locality. The onset of CD was significantly faster, and the symptoms were heavier in participants with a history of CD if compared to naive ones, who, however, also developed some of the symptoms. The repeatedly infected persons had elevated proportion of eosinophils 1 week post exposure (p.e.) and a stronger specific IgG but not IgM response, whereas specific IgE response was not observed. Increased serum levels of IL-4 occurred 1 and 3 week(s) p.e. in all participants. There was high variability in individual immunoblot patterns of IgG response, and no antigen with a universal diagnostic potential was confirmed. The presented analyses suggested that a complex approach can improve the accuracy of the diagnosis of CD, but component data should be interpreted carefully.

• Keywords
• Allergy, Diagnosis, Immunity, Schistosome, Skin, Trichobilharzia,
• MeSH
• Dermatitis immunology   parasitology   MeSH
• Adult MeSH
• Disease Outbreaks MeSH
• Immunoglobulin E blood   MeSH
• Immunoglobulin G blood   MeSH
• Immunoglobulin M blood   MeSH
• Trematode Infections diagnosis   immunology   parasitology   MeSH
• Interleukin-4 blood   MeSH
• Middle Aged MeSH
• Humans MeSH
• Young Adult MeSH
• Follow-Up Studies MeSH
• Antibodies, Protozoan blood   MeSH
• Surveys and Questionnaires MeSH
• Ponds parasitology   MeSH
• Schistosomatidae immunology   MeSH
• Animals MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Young Adult MeSH
• Male MeSH
• Female MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Czech Republic MeSH
• Names of Substances
• IL4 protein, human MeSH Browser
• Immunoglobulin E MeSH
• Immunoglobulin G MeSH
• Immunoglobulin M MeSH
• Interleukin-4 MeSH
• Antibodies, Protozoan MeSH

BACKGROUND: Helminth neuroinfections represent a serious health problem, but host immune mechanisms in the nervous tissue often remain undiscovered. This study aims at in vitro characterization of the response of murine astrocytes and microglia exposed to Trichobilharzia regenti which is a neuropathogenic schistosome migrating through the central nervous system of vertebrate hosts. Trichobilharzia regenti infects birds and mammals in which it may cause severe neuromotor impairment. This study was focused on astrocytes and microglia as these are immunocompetent cells of the nervous tissue and their activation was recently observed in T. regenti-infected mice. RESULTS: Primary astrocytes and microglia were exposed to several stimulants of T. regenti origin. Living schistosomulum-like stages caused increased secretion of IL-6 in astrocyte cultures, but no changes in nitric oxide (NO) production were noticed. Nevertheless, elevated parasite mortality was observed in these cultures. Soluble fraction of the homogenate from schistosomulum-like stages stimulated NO production by both astrocytes and microglia, and IL-6 and TNF-α secretion in astrocyte cultures. Similarly, recombinant cathepsins B1.1 and B2 triggered IL-6 and TNF-α release in astrocyte and microglia cultures, and NO production in astrocyte cultures. Stimulants had no effect on production of anti-inflammatory cytokines IL-10 or TGF-β1. CONCLUSIONS: Both astrocytes and microglia are capable of production of NO and proinflammatory cytokines IL-6 and TNF-α following in vitro exposure to various stimulants of T. regenti origin. Astrocytes might be involved in triggering the tissue inflammation in the early phase of T. regenti infection and are proposed to participate in destruction of migrating schistosomula. However, NO is not the major factor responsible for parasite damage. Both astrocytes and microglia can be responsible for the nervous tissue pathology and maintaining the ongoing inflammation since they are a source of NO and proinflammatory cytokines which are released after exposure to parasite antigens.

• Keywords
• Anti-inflammatory cytokines, Astrocytes, Avian schistosome, Cathepsin B, Microglia, Neuroinfection, Nitric oxide, Proinflammatory cytokines, Trichobilharzia regenti,
• MeSH
• Astrocytes immunology   parasitology   MeSH
• Interleukin-6 metabolism   MeSH
• Cells, Cultured MeSH
• Mice MeSH
• Neuroglia immunology   parasitology   MeSH
• Nitric Oxide metabolism   MeSH
• Schistosomatidae immunology   MeSH
• Tumor Necrosis Factor-alpha metabolism   MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• interleukin-6, mouse MeSH Browser
• Interleukin-6 MeSH
• Nitric Oxide MeSH
• Tumor Necrosis Factor-alpha MeSH

BACKGROUND: The nasal avian schistosome Trichobilharzia regenti spends part of its intravertebrate period of life within the central nervous system. Migration of the parasites can be accompanied by neuromotor disorders or paralysis in natural definitive hosts (ducks) and even in laboratory mammals. Cercariae are also able to penetrate human skin and induce cercarial dermatitis. While the cellular and antibody responses against cercariae and migrating schistosomula have been investigated in mice, little is known about immune reactions in birds. This study first describes the dynamics of antibody response in infected ducks and identifies frequently recognized antigens that may serve as diagnostic markers of infection by T. regenti. METHODS: Groups of 35 domestic ducks and 10 mallards were exposed to different doses of T. regenti cercariae. Sera were collected at predefined time intervals and tested by ELISA for the presence of specific anti-cercarial IgY and IgM. Antigens recognized by the antibodies were identified on Western blots of cercariae and schistosomula. The applicability in immunodiagnostics was statistically evaluated by expression of specificity and sensitivity values for individual antigens. RESULTS: In ELISA, the levels of anti-cercarial IgM peaked on day 15 pi. Increased production of IgY associated with the later phases of infection was observed in most individuals around 20 dpi and culminated 30 dpi. The time course of antibody response did not differ among experimental groups, variations were only observed in the levels of specific IgY which depended rather on the age of ducks at the time of infection than on the infectious dose. On Western blots, 40 cercarial and 7 schistosomular antigens were recognized by IgY from infected ducks. Among them, 4 cercarial antigens of 50, 47, 32 and 19 kDa provided the most sensitive and specific reactions. CONCLUSIONS: Antigens of cercariae and schistosomula elicited distinct antibody response in ducks, which correlated positively with the age of animals at the time of infection. Several antigens originating in cercariae and fewer in schistosomula were recognized by IgY with diverse sensitivity and specificity; only a few seemed to be common to both stages. Four of them were considered as the most promising candidates for immunodiagnostics.

• MeSH
• Antigens, Helminth immunology   MeSH
• Immunoglobulin M blood   MeSH
• Immunoglobulins blood   MeSH
• Trematode Infections blood   immunology   parasitology   veterinary   MeSH
• Ducks * MeSH
• Bird Diseases blood   immunology   parasitology   MeSH
• Antibodies, Helminth blood   MeSH
• Schistosomatidae * MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Antigens, Helminth MeSH
• IgY MeSH Browser
• Immunoglobulin M MeSH
• Immunoglobulins MeSH
• Antibodies, Helminth MeSH

Cercarial dermatitis (swimmer's itch) is a condition caused by infective larvae (cercariae) of a species-rich group of mammalian and avian schistosomes. Over the last decade, it has been reported in areas that previously had few or no cases of dermatitis and is thus considered an emerging disease. It is obvious that avian schistosomes are responsible for the majority of reported dermatitis outbreaks around the world, and thus they are the primary focus of this review. Although they infect humans, they do not mature and usually die in the skin. Experimental infections of avian schistosomes in mice show that in previously exposed hosts, there is a strong skin immune reaction that kills the schistosome. However, penetration of larvae into naive mice can result in temporary migration from the skin. This is of particular interest because the worms are able to migrate to different organs, for example, the lungs in the case of visceral schistosomes and the central nervous system in the case of nasal schistosomes. The risk of such migration and accompanying disorders needs to be clarified for humans and animals of interest (e.g., dogs). Herein we compiled the most comprehensive review of the diversity, immunology, and epidemiology of avian schistosomes causing cercarial dermatitis.

• MeSH
• Biodiversity MeSH
• Disease Outbreaks MeSH
• Host Specificity MeSH
• Humans MeSH
• Bird Diseases parasitology   transmission   MeSH
• Skin Diseases, Parasitic epidemiology   immunology   parasitology   prevention & control   MeSH
• Birds MeSH
• Schistosomiasis epidemiology   immunology   parasitology   prevention & control   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Research Support, N.I.H., Extramural MeSH
• Research Support, U.S. Gov't, Non-P.H.S. MeSH

Cercarial dermatitis (swimmer's itch) is a common non-communicable water-borne disease. It is caused by penetration of the skin by larvae (cercariae) of schistosomatid flukes and develops as a maculopapular skin eruption after repeated contacts with the parasites. The number of outbreaks of the disease is increasing, and cercarial dermatitis can therefore be considered as an emerging problem. Swimmer's itch is mostly associated with larvae of the bird schistosomes of Trichobilharzia spp. Recent results have shown that mammalian infections (including man) manifest themselves as an allergic reaction which is able to trap and eliminate parasites in the skin. Studies on mammals experimentally infected by bird schistosome cercariae revealed, however, that during primary infection, parasites are able to escape from the skin to the lungs or central nervous system. This review covers basic information on detection of the infectious agents in the field and the clinical course of the disease, including other pathologies which may develop after infection by cercariae, and diagnosis of the disease.

• MeSH
• Central Nervous System microbiology   MeSH
• Cercaria immunology   MeSH
• Dermatitis diagnosis   immunology   parasitology   MeSH
• Skin microbiology   pathology   MeSH
• Humans MeSH
• Disease Models, Animal MeSH
• Swimming MeSH
• Lung microbiology   MeSH
• Schistosoma MeSH
• Schistosomiasis complications   diagnosis   immunology   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH