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Schistosomes in the Persian Gulf: novel molecular data, host associations, and life-cycle elucidations. Sci Rep 2022; 12:13461. [PMID: 35931886 PMCID: PMC9356054 DOI: 10.1038/s41598-022-17771-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Accepted: 07/30/2022] [Indexed: 12/03/2022] Open
Abstract
Avian schistosomes, comprise a diverse and widespread group of trematodes known for their surprising ability to switch into new hosts and habitats. Despite the considerable research attention on avian schistosomes as causatives of the human cercarial dermatitis, less it is known about the diversity, geographical range and host associations of the marine representatives. Our molecular analyses inferred from cox1 and 28S DNA sequence data revealed presence of two schistosome species, Ornithobilharzia canaliculata (Rudolphi, 1819) Odhner, 1912 and a putative new species of Austrobilharzia Johnston, 1917. Molecular elucidation of the life-cycle of O. canaliculata was achieved for the first time via matching novel and published sequence data from adult and larval stages. This is the first record of Ornithobilharzia from the Persian Gulf and globally the first record of this genus in a potamidid snail host. Our study provides: (i) new host and distribution records for major etiological agents of cercarial dermatitis and contributes important information on host-parasite relationships; (ii) highlights the importance of the molecular systematics in the assessment of schistosome diversity; and (iii) calls for further surveys to reach a better understanding of the schistosome diversity and patterns of relationships among them, host associations, transmission strategies and distribution coverage.
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Ebbs ET, Loker ES, Bu L, Locke SA, Tkach VV, Devkota R, Flores VR, Pinto HA, Brant SV. Phylogenomics and Diversification of the Schistosomatidae Based on Targeted Sequence Capture of Ultra-Conserved Elements. Pathogens 2022; 11:769. [PMID: 35890014 PMCID: PMC9321907 DOI: 10.3390/pathogens11070769] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 06/20/2022] [Accepted: 06/27/2022] [Indexed: 01/27/2023] Open
Abstract
Schistosomatidae Stiles and Hassall 1898 is a medically significant family of digenetic trematodes (Trematoda: Digenea), members of which infect mammals or birds as definitive hosts and aquatic or amphibious gastropods as intermediate hosts. Currently, there are 17 named genera, for many of which evolutionary interrelationships remain unresolved. The lack of a resolved phylogeny has encumbered our understanding of schistosomatid evolution, specifically patterns of host-use and the role of host-switching in diversification. Here, we used targeted sequence capture of ultra-conserved elements (UCEs) from representatives of 13 of the 17 named genera and 11 undescribed lineages that are presumed to represent either novel genera or species to generate a phylogenomic dataset for the estimation of schistosomatid interrelationships. This study represents the largest phylogenetic effort within the Schistosomatidae in both the number of loci and breadth of taxon sampling. We present a near-comprehensive family-level phylogeny providing resolution to several clades of long-standing uncertainty within Schistosomatidae, including resolution for the placement of the North American mammalian schistosomes, implying a second separate capture of mammalian hosts. Additionally, we present evidence for the placement of Macrobilharzia at the base of the Schistosoma + Bivitellobilharzia radiation. Patterns of definitive and intermediate host use and a strong role for intermediate host-switching are discussed relative to schistosomatid diversification.
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Affiliation(s)
- Erika T. Ebbs
- Department of Biology, Purchase College, The State University of New York, Purchase, NY 10577, USA
| | - Eric S. Loker
- Center for Evolutionary and Theoretical Immunology, Department of Biology, Museum of Southwestern Biology Parasite Division, University of New Mexico, Albuquerque, NM 87131, USA; (E.S.L.); (L.B.); (S.V.B.)
| | - Lijing Bu
- Center for Evolutionary and Theoretical Immunology, Department of Biology, Museum of Southwestern Biology Parasite Division, University of New Mexico, Albuquerque, NM 87131, USA; (E.S.L.); (L.B.); (S.V.B.)
| | - Sean A. Locke
- Department of Biology, University of Puerto Rico at Mayagüez, Box 9000, Mayagüez 00681-9000, Puerto Rico;
| | - Vasyl V. Tkach
- Grand Forks Department of Biology, University of North Dakota, Grand Forks, ND 58202, USA;
| | - Ramesh Devkota
- Vance Granville Community College, Henderson, NC 27536, USA;
| | - Veronica R. Flores
- Laboratorio de Parasitología, INIBIOMA (CONICET-Universidad Nacional del Comahue), Quintral 1250, San Carlos de Bariloche 8400, Argentina;
| | - Hudson A. Pinto
- Department of Parasitology, Institute of Biological Science, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil;
| | - Sara V. Brant
- Center for Evolutionary and Theoretical Immunology, Department of Biology, Museum of Southwestern Biology Parasite Division, University of New Mexico, Albuquerque, NM 87131, USA; (E.S.L.); (L.B.); (S.V.B.)
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Pinto HA, Tenório Mati VL, Melo AL, Brant SV. A putative new genus of avian schistosome transmitted by Biomphalaria straminea (Gastropoda: Planorbidae) in Brazil, with a discussion on the potential involvement in human cercarial dermatitis. Parasitol Int 2022; 90:102607. [PMID: 35659634 DOI: 10.1016/j.parint.2022.102607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 05/28/2022] [Accepted: 05/30/2022] [Indexed: 11/29/2022]
Abstract
Human cercarial dermatitis (HCD) caused by avian schistosomes is an emerging health issue in different parts of the world. Nevertheless, parasite diversity, life cycle, and involvement in HCD remain poorly known or neglected in South America. Herein, we reported data obtained during a long-term malacological survey carried out in Pampulha Reservoir, an urban eutrophic waterbody from Brazil between 2009 and 2012. An ocellate brevifurcate cercaria emerged from 55 of 16,235 (0.34%) specimens of Biomphalaria straminea. Samples of the cercariae were subjected to morphological, experimental, and molecular study (analysis of partial sequences of nuclear 28S and mitochondrial cox1 genes). The molecular analysis revealed that the larva corresponds to an avian schistosome; however, it does not correspond to any named genus. A close related isolate was previously reported in Biomphalaria sudanica from Kenya (molecular divergences of 0.54% and 9.62% for 28S and cox1, respectively). The morphology of this cercaria was compared with other avian schistosome larvae from Biomphalaria spp. Attempts to infect experimentally ducks (Cairina moschata) and mice revealed cutaneous manifestations after exposure to cercariae, but adult parasites were not obtained in these hosts. Phylogenetic analysis suggests this parasite is a putative new genus and species of avian schistosome. The potential involvement of the larvae herein described in cases of HCD in Brazil cannot be ruled out. Surprisingly, HCD was not reported in the country so far, which can be related to difficulties in its diagnosis in areas of overlap with human schistosomes.
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Affiliation(s)
- Hudson A Pinto
- Laboratório de Biologia de Trematoda, Department of Parasitology, Institute of Biological Science, Universidade Federal de Minas Gerais, Brazil.
| | - Vitor L Tenório Mati
- Department of Medicine, Universidade Federal de Lavras, Lavras, Minas Gerais, Brazil
| | - Alan L Melo
- Laboratório de Biologia de Trematoda, Department of Parasitology, Institute of Biological Science, Universidade Federal de Minas Gerais, Brazil
| | - Sara V Brant
- Museum of Southwestern Biology Division of Parasites, Department of Biology, University of New Mexico, Albuquerque, NM, USA
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Loker ES, DeJong RJ, Brant SV. Scratching the Itch: Updated Perspectives on the Schistosomes Responsible for Swimmer's Itch around the World. Pathogens 2022; 11:587. [PMID: 35631108 PMCID: PMC9144223 DOI: 10.3390/pathogens11050587] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/09/2022] [Accepted: 05/13/2022] [Indexed: 01/01/2023] Open
Abstract
Although most studies of digenetic trematodes of the family Schistosomatidae dwell on representatives causing human schistosomiasis, the majority of the 130 identified species of schistosomes infect birds or non-human mammals. The cercariae of many of these species can cause swimmer's itch when they penetrate human skin. Recent years have witnessed a dramatic increase in our understanding of schistosome diversity, now encompassing 17 genera with eight more lineages awaiting description. Collectively, schistosomes exploit 16 families of caenogastropod or heterobranch gastropod intermediate hosts. Basal lineages today are found in marine gastropods and birds, but subsequent diversification has largely taken place in freshwater, with some reversions to marine habitats. It seems increasingly likely that schistosomes have on two separate occasions colonized mammals. Swimmer's itch is a complex zoonotic disease manifested through several different routes of transmission involving a diversity of different host species. Swimmer's itch also exemplifies the value of adopting the One Health perspective in understanding disease transmission and abundance because the schistosomes involved have complex life cycles that interface with numerous species and abiotic components of their aquatic environments. Given the progress made in revealing their diversity and biology, and the wealth of questions posed by itch-causing schistosomes, they provide excellent models for implementation of long-term interdisciplinary studies focused on issues pertinent to disease ecology, the One Health paradigm, and the impacts of climate change, biological invasions and other environmental perturbations.
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Affiliation(s)
- Eric S. Loker
- Center for Evolutionary and Theoretical Immunology, Parasites Division, Museum of Southwestern Biology, Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA;
| | - Randall J. DeJong
- Department of Biology, Calvin University, Grand Rapids, MI 49546, USA;
| | - Sara V. Brant
- Center for Evolutionary and Theoretical Immunology, Parasites Division, Museum of Southwestern Biology, Department of Biology, University of New Mexico, Albuquerque, NM 87131, USA;
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