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

Swimmer's itch is a re-emerging human disease caused by bird schistosome cercariae, which can infect bathing or working people in water bodies. Even if cercariae fail after penetrating the human skin, they can cause dangerous symptoms in atypical mammal hosts. One of the natural methods to reduce the presence of cercariae in the environment could lie in the introduction of non-host snail species to the ecosystem, which is known as the "dilution" or "decoy" effect. The caenogastropod Potamopyrgus antipodarum-an alien in Europe-could be a good candidate against swimmer's itch because of its apparent resistance to invasion by European bird schistosome species and its high population density. As a pilot study on this topic, we have carried out a laboratory experiment on how P. antipodarum influences the infestation of the intermediate host Radix balthica (a native lymnaeid) by the bird schistosome Trichobilharzia regenti. We found that the co-exposure of 200 P. antipodarum individuals per one R. balthica to the T. regenti miracidia under experimental conditions makes the infestation ineffective. Our results show that a non-host snail population has the potential to interfere with the transmission of a trematode via suitable snail hosts.

• Keywords
• Miracidia, Potamopyrgus antipodarum, Radix balthica, Trichobilharzia regenti, “Decoy effect”,
• Publication type
• Journal Article MeSH

Nasal bird schistosomes can cause bilharziosis in birds and have the potential to cause swimmer's itch in humans. We determined the prevalence of bird schistosomes in 106 mallards (Anas plathyrhynchos) from 11 water sources in Germany from 2014. Dissections were performed focusing on parasitic infections of the neural system. Infections with Trichobilharzia regenti (Horák et al. 1998) were found in 21% of the birds (n = 22), whereas Bilharziella polonica (Kowalewski 1895) were found between the brain membranes (meninges) and the brain, in the spinal cord or in the intestine of 12% of the mallards (n = 13). No significant influence of sex, age, and body condition between infected and non-infected animals was observed. Our study provides the first description of B. polonica from the neural system of birds and provides an epidemiological understanding of a parasite of human health concern.

• Keywords
• Bilharziella polonica, Bird schistosomes, Mallard, Trichobilharzia regenti,
• MeSH
• Animals, Wild parasitology   MeSH
• Trematode Infections parasitology   veterinary   MeSH
• Ducks parasitology   MeSH
• Humans MeSH
• Bird Diseases parasitology   MeSH
• Nervous System parasitology   MeSH
• Schistosoma genetics   isolation & purification   physiology   MeSH
• Schistosomatidae genetics   isolation & purification   physiology   MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Geographicals
• Germany MeSH

Cercariae of bird schistosomes (Trichobilharzia szidati and Trichobilharzia regenti) were mechanically stimulated to transform to schistosomula and kept in different cultivation media supplemented with duck red blood cells and/or homogenized nervous tissue. The development under in vitro conditions was compared with that in vivo, using the following characters: emptying of penetration glands, surface changes, food uptake, and growth of early schistosomula. The results show that the cultivation medium routinely used for human schistosomes is also suitable for mass production of early schistosomula of bird schistosomes, including the unique nasal species-T. regenti. The changes observed resemble those present in worms developing in vivo; therefore, the in vitro produced early schistosomula might be used for further studies of host-parasite interactions.

• MeSH
• Animal Structures parasitology   MeSH
• Trematode Infections parasitology   veterinary   MeSH
• Culture Media chemistry   MeSH
• Bird Diseases parasitology   MeSH
• Nasal Cavity parasitology   MeSH
• Parasitology methods   MeSH
• Birds MeSH
• Schistosomatidae growth & development   isolation & purification   MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Culture Media MeSH

Cercariae of the nasal bird schistosome Trichobilharzia regenti are able to penetrate into mammalian skin and migrate to the mouse central nervous system (CNS) causing tissue injury in certain cases. Our study shows that the severity of T. regenti pathologies in the CNS closely depends on the host immune status. During the primary infection of immunocompetent mice, the parasites evoked an acute inflammatory reaction in the skin and the CNS involving focal oedema and cellular infiltration of the tissue. Challenge infections resulted in the development of extensive inflammatory foci in the host skin which precluded the subsequent migration of the schistosomula to the CNS. On the other hand, during primary as well as challenge infections of immunodeficient mice (SCID), no significant immune response against the parasites was detected in any of the host organs examined; however, in contrast to immunocompetent mice, the infections were frequently manifested by severe leg paralysis.

• MeSH
• Central Nervous System Helminthiasis immunology   parasitology   pathology   MeSH
• Immunocompetence MeSH
• Trematode Infections immunology   parasitology   pathology   MeSH
• Ducks parasitology   MeSH
• Skin immunology   parasitology   pathology   MeSH
• Spinal Cord parasitology   pathology   MeSH
• Mice, SCID MeSH
• Mice MeSH
• Bird Diseases parasitology   MeSH
• Schistosomatidae pathogenicity   MeSH
• Severity of Illness Index MeSH
• Animals MeSH
• Check Tag
• Mice MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH