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Sara V. Brant - One of the best experts on this subject based on the ideXlab platform.
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Migratory routes, domesticated birds and Cercarial Dermatitis: the distribution of Trichobilharzia franki in Northern Iran.
Parasite (Paris France), 2021Co-Authors: Keyhan Ashrafi, Meysam Sharifdini, Abbas Darjani, Sara V. BrantAbstract:Background : One of the major migration routes for birds going between Europe and Asia is the Black Sea-Mediterranean route that converges on the Volga Delta, continuing into the area of the Caspian Sea. Cercarial Dermatitis is a disorder in humans caused by schistosome trematodes that use aquatic birds and snails as hosts and is prevalent in areas of aquaculture in Northern Iran. Before the disorder can be addressed, it is necessary to determine the etiological agents and their host species. This study aimed to document whether domestic mallards are reservoir hosts and if so, to characterize the species of schistosomes. Previous work has shown that domestic mallards are reservoir hosts for a nasal schistosome. Results : In 32 of 45 domestic mallards (Anas platyrhynchos domesticus ) (71.1%), the schistosome Trichobilharzia franki , previously reported only from Europe, was found in visceral veins. Morphological and molecular phylogenetic analysis confirmed the species designation. These findings extend the range of T. franki from Europe to Eurasia. Conclusion : The occurrence of Cercarial Dermatitis in Iran is high in areas of aquaculture. Previous studies in the area have shown that domestic mallards are reservoir hosts of T. regenti , a nasal schistosome and T. franki, as shown in this study. The genetic results support the conclusion that populations of T. franki from Iran are not differentiated from populations in Europe. Therefore, the schistosomes are distributed with their migratory duck hosts, maintaining the gene flow across populations with compatible snail hosts in Iran.
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Genetic diversity of an avian nasal schistosome causing Cercarial Dermatitis in the Black Sea-Mediterranean migratory route
Parasitology Research, 2018Co-Authors: Keyhan Ashrafi, Meysam Sharifdini, Alireza Nouroosta, Mohammad Reza Mahmoudi, Behnaz Rahmati, Sara V. BrantAbstract:This study is part of an effort to document the diversity of avian schistosomes in ducks and snails in Northern Iran, a major flyway (Black Sea/Mediterranean) for migratory birds and where Cercarial Dermatitis (CD) is prevalent in rice growing areas. CD is an allergic skin reaction from schistosome trematodes that emerge from aquatic snails. Most CD cases are reported from recreational swimmers or aquaculture farmers. Much of the work on the epidemiology of CD has focused in recreational waters in the Americas and Europe, with fewer studies in aquaculture, particularly in Iran. The artificial environment at aquaculture sites support dense populations of snails that are hosts to schistosomes, as well as domestic ducks. Thus, are domestic ducks reservoir hosts of species of Trichobilharzia , one of the main etiological agents of CD in Northern Iran? This study focused on a survey of domestic ducks for the presence of the nasal schistosome, T. regenti , that has been reported widely in Europe. Trichobilharzia regenti were found in domestic ducks in the Guilan Province of Iran based on morphological and molecular analyses. The presence of this species in Northern Iran indicates that the domestic duck can serve as a reservoir host for this species and that one of the local snail species is likely the intermediate host. The continued study and surveillance of this species is important because it is a neuropathic schistosome that can use a diversity of bird definitive hosts and Radix snails that are widespread across Eurasia.
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Putative new genera and species of avian schistosomes potentially involved in human Cercarial Dermatitis in the Americas, Europe and Africa.
Acta tropica, 2017Co-Authors: Hudson Alves Pinto, Alan Lane De Melo, Eduardo A. Pulido-murillo, Sara V. BrantAbstract:New larval avian schistosomes found in planorbid snails from Brazil and USA were used for morphological and molecular studies. Eggs with a distinctive long polar filament were found in ducks infected experimentally with Brazilian cercariae. Similar eggs were reported previously in wild or experimentally infected anatids from Brazil, South Africa, and the Czech Republic. Molecular phylogenetic analyses showed that the North American and European schistosomes are sister taxa, which are both sister to the Brazilian species. However, these clades do not group with any named genus. Molecular data plus egg morphology suggest that these are new putative genera and species of avian schistosomes that can cause human Cercarial Dermatitis in the Americas, Africa and Europe.
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Schistosomes with wings: how host phylogeny and ecology shape the global distribution of Trichobilharzia querquedulae (Schistosomatidae).
International journal for parasitology, 2016Co-Authors: Erika T. Ebbs, Eric S. Loker, Norm E. Davis, Verónica Flores, Aylén Anabella Veleizán, Sara V. BrantAbstract:Abstract Migratory waterfowl play an important role in the maintenance and spread of zoonotic diseases worldwide. An example is Cercarial Dermatitis, caused when larval stages of schistosomes that normally develop in birds penetrate human skin. Members of the genus Trichobilharzia (Schistosomatidae), transmitted mainly by ducks, are considered to be major etiological agents of Cercarial Dermatitis globally. To better understand the diversity and distribution of Trichobilharzia spp., we surveyed ducks from the United States, eastern Canada, Argentina, South Africa and New Zealand. To aid in species identification of the Trichobilharzia worms recovered, regions of the Cox1, ND4 and ITS1 were sequenced. Furthermore, we provide molecular phylogenetic evidence for the cosmopolitan distribution and trans-hemispheric gene flow for one species, Trichobilharzia querquedulae, previously thought to be restricted to North America. These new samples from endemic non-migratory duck species indicate that T. querquedulae transmission occurs within each of the regions we sampled and that it is specific to the blue-winged + silver teal duck clade. Prevalence within this host group is >95% across the known range of T. querquedulae, indicating that transmission is common. Genetic divergence is evenly distributed among continents, and no phylogenetic structure associated with geography was observed. The results provide strong support for the global distribution and transmission of T. querquedulae and represent, to our knowledge, the first report of a cosmopolitan schistosome confirmed by genetic data. These data are the first known to support trans-hemispheric genetic exchange in a species responsible for causing Cercarial Dermatitis, indicating that the epidemiology of this group of poorly known zoonotic parasites is more complex than previously expected.
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Avian Schistosomes and Outbreaks of Cercarial Dermatitis
Clinical microbiology reviews, 2015Co-Authors: Petr Horák, Libor Mikeš, Lucie Lichtenbergová, Vladimír Skála, Miroslava Soldánová, Sara V. BrantAbstract:SUMMARY Cercarial Dermatitis (swimmer9s 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.
Mostafa Essalat - One of the best experts on this subject based on the ideXlab platform.
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A study on Cercarial Dermatitis in Khuzestan province, south western Iran
BMC Public Health, 2003Co-Authors: Ali Farahnak, Mostafa EssalatAbstract:Background Cercarial Dermatitis' or swimmer's itch' is an itchy inflammatory response to the penetration of the skin by non-human schistosome parasites. In the hot season, (May to September) in Khuzestan province in the south west of Iran, swimming in canals and agriculture activities in swampy areas are common. This survey was made on people from villages north of Ahwaz city in south west Iran, to estimate Cercarial Dermatitis in this region. Methods 2000 people were observed for clinical signs of Cercarial Dermatitis. Also 2000 Lymnaea gedrosiana snails were collected from agriculture canals and examined for animal schistosome cercariae during 1998–2000. Results From this survey 1.1% of people had pruritic maculopapular rash on their feet, hands or other parts of body. From the total of examined snails, 2.4% were found to be infected with bird schistosome cercariae including Trichobilharzia species. Conclusion Cercarial Dermatitis could be a health problem in this area. This is the first report of Cercarial Dermatitis from this region of Iran.
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A study on Cercarial Dermatitis in Khuzestan province, south western Iran
BMC public health, 2003Co-Authors: A Farahnak, Mostafa EssalatAbstract:Cercarial Dermatitis' or swimmer's itch' is an itchy inflammatory response to the penetration of the skin by non-human schistosome parasites. In the hot season, (May to September) in Khuzestan province in the south west of Iran, swimming in canals and agriculture activities in swampy areas are common. This survey was made on people from villages north of Ahwaz city in south west Iran, to estimate Cercarial Dermatitis in this region. 2000 people were observed for clinical signs of Cercarial Dermatitis. Also 2000 Lymnaea gedrosiana snails were collected from agriculture canals and examined for animal schistosome cercariae during 1998–2000. From this survey 1.1% of people had pruritic maculopapular rash on their feet, hands or other parts of body. From the total of examined snails, 2.4% were found to be infected with bird schistosome cercariae including Trichobilharzia species. Cercarial Dermatitis could be a health problem in this area. This is the first report of Cercarial Dermatitis from this region of Iran.
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A Parasitological and Clinical Survey on Cercarial Dermatitis in Khuzestan Province, South Western Iran
Iranian Journal of Public Health, 2003Co-Authors: A Farahnak, Mostafa EssalatAbstract:Cercarial Dermatitis or swimmers’ itch is an itchy inflammatory response to the penetration of the skin by non-human schistosome parasites. In the hot season, May to September, in Khuzestan province in the south west of Iran, swimming in canals and agriculture activities in swampy areas are common. This survey was made on people from villages north of Ahwaz city in south west Iran, to estimate Cercarial Dermatitis in this region. For this purpose 2000 people were observed for clinical signs of Cercarial Dermatitis. Also 2000 Lymnaea gedrosiana snails were collected from agriculture canals and examined for animal schistosome cercariae during 1998-2000. From this survey 1.1% of people had pruritic maculopapular rash on their feet, hands or other parts of body. From the total of examined snails, 2.4% were found to be infected with bird schistosome cercariae including Trichobilharzia sp. Cercarial Dermatitis could be a health problem in this area. This is the first report of Cercarial Dermatitis from this region of Iran.
Petr Horák - One of the best experts on this subject based on the ideXlab platform.
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Cercarial Dermatitis: a systematic follow-up study of human cases with implications for diagnostics
Parasitology Research, 2018Co-Authors: Tomáš Macháček, Petr Horák, Libuše Turjanicová, Jana Bulantová, Jiří Hrdý, Libor MikešAbstract: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.
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Historical analysis of the type species of the genus Trichobilharzia Skrjabin et Zakharov, 1920 (Platyhelminthes: Schistosomatidae)
Zootaxa, 2016Co-Authors: Jitka A. Aldhoun, Petr Kment, Petr HorákAbstract:Trichobilharzia Skrjabin & Zakharov, 1920 is known as the most species-rich genus of the blood fluke family Schistosomatidae. To date, more than 40 species have been described, even though validity of some of them is questionable (Horak et al . 2002). Members of the genus use various birds as final hosts, but they attract attention mostly as causative agents of hypersensitive skin reaction (Cercarial Dermatitis or swimmer’s itch) in mammals including humans. As this is one of the
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Avian Schistosomes and Outbreaks of Cercarial Dermatitis
Clinical microbiology reviews, 2015Co-Authors: Petr Horák, Libor Mikeš, Lucie Lichtenbergová, Vladimír Skála, Miroslava Soldánová, Sara V. BrantAbstract:SUMMARY Cercarial Dermatitis (swimmer9s 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.
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Cercarial Dermatitis, a Neglected Allergic Disease
Clinical Reviews in Allergy & Immunology, 2013Co-Authors: Libuše Kolářová, Petr Horák, Karl Skírnisson, Helena Marečková, Michael DoenhoffAbstract: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.
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Snails, waterfowl and Cercarial Dermatitis
Freshwater Biology, 2010Co-Authors: Petr Horák, Libuše KolářováAbstract:SUMMARY 1. Birds and snails are suitable hosts for many parasites, including helminths in general and trematodes in particular. Among trematodes, members of the family Schistosomatidae with two-host life cycles (snails as intermediate hosts and birds as definitive hosts) are successful and abundant pathogens. Their transmission between birds and snails in nature can be influenced by many abiotic and biotic factors. 2. In snails, the prevalence of schistosome infections and production of cercariae can be influenced by host immunological susceptibility ⁄ physiological suitability, snail age ⁄ size, interspecific competition of trematode larvae, etc. Schistosomes are able to survive in overwintering snails, serving as a source of infection in spring. 3. Birds may also differ in susceptibility to and prevalence rates of schistosome infections. They are long-range vectors of schistosomes. 4. Climate changes influence behaviour of migratory birds, lead to shifts in season- or temperature-dependent processes in snails and schistosomes, and influence the frequency of schistosome transmission and intensity of infection. Also, eutrophication can increase the growth of snail populations and transmission of bird schistosomes. 5. Dispersal of bird schistosomes to new regions and an increased availability (local abundance) of the snail hosts, together with the use of new water reservoirs (e.g., in higher latitudes) for recreational purposes, may contribute to a higher number of outbreaks of Cercarial Dermatitis.
Libuše Kolářová - One of the best experts on this subject based on the ideXlab platform.
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REVIEW ARTICLE Schistosomes causing Cercarial Dermatitis: a mini-review of current trends in systematics and of host specificity and pathogenicity
2016Co-Authors: Libuše KolářováAbstract:Abstract. The human infection known under the names Cercarial Dermatitis or swimmers ’ itch is generally associated with swimming in lakes all over the world, however, a number of outbreaks of Cercarial Dermatitis developing in salt or brackish waters are also reported. The disease presents as allergic reaction which is able to trap and eliminate the parasites in the skin. However, the infection can be linked to more than skin symptoms under certain circumstances. Recent studies on bird schisto-somes have shown that during primary infections of noncompatible hosts (mice) the parasites may migrate through visceral and nervous tissues of mammals. Up to date, Cercarial Dermatitis has been mostly associated with the cercariae of bird schistosomes of the genus Trichobilharzia. Recent findings of new genera and species indicate, however, broader spectrum of causative agents of the disease with different life cycles, host specificity and pathogenicity. Cercarial Dermatitis is a common non-communicable water-borne disease which has been recently regarded as an emerging infection (de Gentile et al. 1996). Clini-cal symptoms of Cercarial Dermatitis were firstly re-ported by Fujii in 1887 (cited by Oda 1973) and the causative agents, schistosome larvae (cercariae), were identified by Cort in 1928 in the USA. Shortly thereaf
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Cercarial Dermatitis, a Neglected Allergic Disease
Clinical Reviews in Allergy & Immunology, 2013Co-Authors: Libuše Kolářová, Petr Horák, Karl Skírnisson, Helena Marečková, Michael DoenhoffAbstract: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.
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Snails, waterfowl and Cercarial Dermatitis
Freshwater Biology, 2010Co-Authors: Petr Horák, Libuše KolářováAbstract:SUMMARY 1. Birds and snails are suitable hosts for many parasites, including helminths in general and trematodes in particular. Among trematodes, members of the family Schistosomatidae with two-host life cycles (snails as intermediate hosts and birds as definitive hosts) are successful and abundant pathogens. Their transmission between birds and snails in nature can be influenced by many abiotic and biotic factors. 2. In snails, the prevalence of schistosome infections and production of cercariae can be influenced by host immunological susceptibility ⁄ physiological suitability, snail age ⁄ size, interspecific competition of trematode larvae, etc. Schistosomes are able to survive in overwintering snails, serving as a source of infection in spring. 3. Birds may also differ in susceptibility to and prevalence rates of schistosome infections. They are long-range vectors of schistosomes. 4. Climate changes influence behaviour of migratory birds, lead to shifts in season- or temperature-dependent processes in snails and schistosomes, and influence the frequency of schistosome transmission and intensity of infection. Also, eutrophication can increase the growth of snail populations and transmission of bird schistosomes. 5. Dispersal of bird schistosomes to new regions and an increased availability (local abundance) of the snail hosts, together with the use of new water reservoirs (e.g., in higher latitudes) for recreational purposes, may contribute to a higher number of outbreaks of Cercarial Dermatitis.
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Antibody responses induced by Trichobilharzia regenti antigens in murine and human hosts exhibiting Cercarial Dermatitis.
Parasite immunology, 2008Co-Authors: Lucie Lichtenbergová, Petr Horák, Libuše Kolářová, Libor Mikeš, Petra Kolbeková, Pavlína Kouřilová, Martin Kašný, Helmut L. Haas, Gabriele Schramm, Adrian P. MountfordAbstract:Cercariae of bird schistosomes (genus Trichobilharzia) are able to penetrate the skin of mammals (noncompatible hosts), including humans, and cause a Th2-associated inflammatory cutaneous reaction termed Cercarial Dermatitis. The present study measured the antibody reactivity and antigen specificity of sera obtained after experimental infection of mice and natural infection of humans. Sera from mice re-infected withT. regenti showed a bias towards the development of antigen-specific IgM and IgG1 antibodies and elevated levels of total serum IgE, indicative of a Th2 polarized immune response. We also demonstrate that cercariae are a source of antigens triggering IL-4 release from basophils collected from healthy human volunteers. Analysis of sera from patients with a history of Cercarial Dermatitis revealed elevated levels of Cercarial-specific IgG, particularly for samples collected from adults (> 14 years old) comparedwith children (8–14 years old), although elevated levels of antigen-specific IgE were not detected. In terms of antigen recognition, IgG and IgE antibodies in the sera of both mice and humans preferentially bound an antigen of 34 kDa. The 34 kDa molecule was present in both homogenate of cercariae, as well as Cercarial excretory/secretory products, and we speculate it may represent a major immunogen initiating the Th2-immune response associated with Cercarial Dermatitis.
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Bird schistosomes: do they die in mammalian skin?
Trends in parasitology, 2001Co-Authors: Petr Horák, Libuše KolářováAbstract:The cercariae of bird schistosomes, released from the intermediate water snail host, actively penetrate the skin of both birds and mammals. Whereas in birds the infection leads to worm maturation and egg production, in the mammalian hosts skin invasion is accompanied by Cercarial Dermatitis (swimmer's itch, clam-digger's disease) and the fate of the parasites is not clear. Here, we review bird schistosomes as causative agents of Cercarial Dermatitis, underline adaptations of bird schistosomes to their life in vertebrate hosts, and discuss potential risks caused by the parasites migrating in humans.
Ruth S. Kirk - One of the best experts on this subject based on the ideXlab platform.
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Itchy and scratchy? An investigation of human Cercarial Dermatitis in the UK
2018Co-Authors: Ricarda Micallef, Ruth S. KirkAbstract:Human Cercarial Dermatitis (CD) or cercariosis is a cutaneous allergic response caused by repeated penetration of avian and mammalian schistosome cercariae and possibly non-schistosomatid cercariae. It is an emerging and re-emerging disease frequently reported in Europe and the USA in association with recreational lakes inhabited by snail intermediate hosts and waterfowl definitive hosts for Trichobilharzia spp. There is insufficient information about the occurrence and causative agents of CD in the UK and the condition is underdiagnosed due to confusion with insect bites and lack of a reporting system. Reports of CD in the UK are increasing in frequency via social media, partly due to the popularity of open water swimming, although the full extent of CD as a health issue is not known. This is the first study in the UK to explore occurrence of CD and its impacts on open water swimmers. Following ethical approval from Kingston University Ethics Committee, open water swimmers were contacted via swimming clubs and on social media to complete a 14-question survey on Survey Monkey on CD and open water swimming behaviour during 2016. A total of 62 responses (61% female: 39% male, age range: 76) were received. Self-diagnosed reports of CD were recorded from 38 sites, mainly in England, comprising freshwater lakes and rivers except for one marine site in Cornwall. Interestingly, not all swimmers experienced symptoms at known CD sites and they reported symptoms from April to November, beyond the usual seasonal period of Cercarial emergence. CD does not discourage open water swimming for the majority due to strong motivators for the sport. Multiple preventative measures and treatments were undertaken, mainly following advice from friends, pharmacies and the internet. Wet suits were not worn by the majority and do not appear to be effective in preventing CD. The efficacy of removing snail intermediate hosts at one site is currently being tested and more demographic data will be needed in future studies to identify reasons for variable responses to exposure.
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Trichobilharzia species in the UK : a cause for concern?
2016Co-Authors: Ruth S. Kirk, Scott P Lawton, Elisha Enabulele, Tony WalkerAbstract:The popularity of recreational water activities such as triathlons and natural swimming has increased worldwide. However, the use of water for leisure poses a number of health risks from viral, bacterial and parasitic infections. Protists are considered to be the most important parasitic causes of water related diseases, but recent evidence suggests that bird schistosomes of the genus Trichobilharzia should also be considered as risks to public health. Trichobilharzia species are widely reported agents of human Cercarial Dermatitis (swimmer's itch), which is currently regarded as a re-emerging disease in Europe. Repeated exposure to cercariae emerging from aquatic snails elicits an inflammatory response in the skin which can lead to further symptoms such as fever. Although some cases of Cercarial Dermatitis have been reported in the UK, little is known about the distribution and diversity of schistosomatid blood flukes that cause the disease or their snail intermediate hosts. Recent studies by our research group using a range of molecular markers have confirmed the occurrence of two agents of Cercarial Dermatitis in the UK. Trichobilharzia franki was identified from Radix auricularia in Hampshire, Southern England and from R. balthica in Wester Ross, Western Scotland. Trichobilharzia szidati was identified from Lymnaea stagnalis in Norfolk. The implications of these findings are discussed, particularly in relation to climate change and requirements for further monitoring, economic impacts and improved public awareness of Cercarial Dermatitis.
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Identification of a major causative agent of human Cercarial Dermatitis, Trichobilharzia franki (Müller and Kimmig 1994), in southern England and its evolutionary relationships with other European populations
Parasites & vectors, 2014Co-Authors: Scott P Lawton, Rivka M Lim, Juliet P Dukes, Richard T. Cook, Anthony J. Walker, Ruth S. KirkAbstract:Background Trichobilharzia is the most species rich and widely distributed genus of schistosomes and is known throughout Europe and North America as an agent of human Cercarial Dermatitis. The disease is caused by an acute allergic reaction in the skin that develops as a consequence of repeated contact with water containing schistosomatid cercariae. However, despite historical outbreaks of the disease, there are no published records of accurately identified Trichobilharzia species from the UK.
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Identification of a major causative agent of human Cercarial Dermatitis, Trichobilharzia franki (Müller and Kimmig 1994), in southern England and its evolutionary relationships with other
2014Co-Authors: Scott P Lawton, Rivka M Lim, Juliet P Dukes, Anthony J. Walker, Ruth S. KirkAbstract:Background: Trichobilharzia is the most species rich and widely distributed genus of schistosomes and is known throughout Europe and North America as an agent of human Cercarial Dermatitis. The disease is caused by an acute allergic reaction in the skin that develops as a consequence of repeated contact with water containing schistosomatid cercariae. However, despite historical outbreaks of the disease, there are no published records of accurately identified Trichobilharzia species from the UK. Methods: Two hundred Radix auricularia (L.) were sampled from a recreational fishing lake in Hampshire and emerging schistosomatid cercariae were collected for microscopy and DNA extraction. General morphological description of the cercariae was performed, alongside sequencing and phylogenetic analysis of the 28S ribosomal DNA for accurate species identification as well as comparisons of ITS1 in order to identify evolutionary affinities with other European populations. All molecular comparisons were performed using published sequences. Results: The phylogenetic analysis of 28S sequences identified the cercariae as Trichobilharzia franki. Two unique British ITS1 haplotypes were identified which were most closely related to haplotypes of T. franki populations from France. Haplotype network analysis indicated the mixing of T. franki populations throughout Europe. It is suggested that parasite distribution is the probable result of the movement of migratory waterfowl. Conclusions: This is the first accurate record of T. franki in the UK. The movement of T. franki with waterfowl could pose a considerable human health risk, as in mainland Europe, and signifies T. franki-associated human Cercarial Dermatitis as a re-emerging disease in the UK.