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Scott ME. Helminth-host-environment interactions: Looking down from the tip of the iceberg. J Helminthol 2023; 97:e59. [PMID: 37486085 DOI: 10.1017/s0022149x23000433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
In 1978, the theory behind helminth parasites having the potential to regulate the abundance of their host populations was formalized based on the understanding that those helminth macroparasites that reduce survival or fecundity of the infected host population would be among the forces limiting unregulated host population growth. Now, 45 years later, a phenomenal breadth of factors that directly or indirectly affect the host-helminth interaction has emerged. Based largely on publications from the past 5 years, this review explores the host-helminth interaction from three lenses: the perspective of the helminth, the host, and the environment. What biotic and abiotic as well as social and intrinsic host factors affect helminths? What are the negative, and positive, implications for host populations and communities? What are the larger-scale implications of the host-helminth dynamic on the environment, and what evidence do we have that human-induced environmental change will modify this dynamic? The overwhelming message is that context is everything. Our understanding of second-, third-, and fourth-level interactions is extremely limited, and we are far from drawing generalizations about the myriad of microbe-helminth-host interactions.Yet the intricate, co-evolved balance and complexity of these interactions may provide a level of resilience in the face of global environmental change. Hopefully, this albeit limited compilation of recent research will spark new interdisciplinary studies, and application of the One Health approach to all helminth systems will generate new and testable conceptual frameworks that encompass our understanding of the host-helminth-environment triad.
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Affiliation(s)
- M E Scott
- Institute of Parasitology, McGill University (Macdonald Campus), 21,111 Lakeshore Road, Ste-Anne de Bellevue, QuebecH9X 3V9, Canada
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2
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Tookhy NA, Isa NMM, Mansor R, Rahaman YA, Ahmad NI, Bui DT, Idris LH, Hamzah NH, Zulkifli N. Morphological and molecular identification of lymnaeid snail and trematodes cercariae in different water bodies in Perak, Malaysia. Parasitol Res 2023:10.1007/s00436-023-07845-z. [PMID: 37145225 DOI: 10.1007/s00436-023-07845-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 04/07/2023] [Indexed: 05/06/2023]
Abstract
Lymnaeid snails play a crucial role in the transmission of trematode cercariae as an intermediate host that can infect humans, ruminants like buffalo, and other animals, resulting in serious economic losses. The purpose of the study was to identify the morphological and molecular characteristics of snails and cercariae collected from water bodies near buffalo farms that were integrated with palm oil in Perak, Malaysia. The presence or absence of snails in 35 water bodies was examined via cross-sectional study. From three marsh wetlands, 836 lymnaeid snails were gathered in total. Each snail's shell was morphologically identified to determine its family and species. The cercarial stage inside each snail's body was observed using the crushing method and trematode cercariae types were determined. In addition, the target gene Cytochrome c oxidase subunit 1 (Cox1) and the ribosomal internal transcribed spacer 2 (ITS2) region were used to identify the snail species and cercarial types according to the species level. The findings indicated that the collected snails belong to the family lymnaeidae and Radix rubiginosa species. In snails, the cercarial emergence infection rate was 8.7%. Echinostome, xiphidiocercariae, gymnocephalous, brevifurcate-apharyngeate distome cercariae (BADC), and longifurcate-pharyngeal monostome cercariae (LPMC) are the five morphological cercarial types that were observed. The cercariae were identified using morphological and molecular techniques, and they are members of the four families which are Echinostomatidae, Plagiorchiidae, Fasciolidae, and Schistosomatidae. Interestingly, this is the first study on R. rubiginosa and several trematode cercariae in Perak water bodies near buffalo farms that are integrated with palm oil. In conclusion, our research shown that a variety of parasitic trematodes in Perak use R. rubiginosa as an intermediate host.
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Affiliation(s)
- Nazir Ahmad Tookhy
- Department of Paraclinic, Faculty of Veterinary Sciences, Herat University, Herat, Afghanistan
- Department of Veterinary Pathology and Microbiology, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - Nur Mahiza Md Isa
- Department of Veterinary Pathology and Microbiology, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia.
| | - Rozaihan Mansor
- Department of Farm and Exotic Animals Medicine and Surgery, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - Yasmin Abd Rahaman
- Department of Veterinary Laboratory Diagnosis, Faculty of Veterinary Medicine, Universiti Putra Malaysia (UPM), Selangor, 43400, Serdang, Malaysia
| | - Nur Indah Ahmad
- Department of Veterinary Pathology and Microbiology, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - Dung Thi Bui
- Institute of Ecology and Biological Resources, Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Ha Noi, Vietnam
- Graduate University of Science and Technology, Vietnam Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Ha Noi, Vietnam
| | - Lokman Hakim Idris
- Department of Veterinary Pre-Clinical Science, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
| | - Noor Hazfalinda Hamzah
- Forensic Science Program, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, 43600, Bangi, Malaysia
| | - Norhadila Zulkifli
- Department of Veterinary Pathology and Microbiology, Faculty of Veterinary Medicine, Universiti Putra Malaysia, 43400, Serdang, Selangor, Malaysia
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Jorge F, Dheilly NM, Froissard C, Poulin R. Association between parasite microbiomes and caste development and colony structure in a social trematode. Mol Ecol 2022; 31:5608-5617. [PMID: 36004565 PMCID: PMC9826137 DOI: 10.1111/mec.16671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 08/17/2022] [Accepted: 08/19/2022] [Indexed: 01/11/2023]
Abstract
Division of labour through the formation of morphologically and functionally distinct castes is a recurring theme in the evolution of animal sociality. The mechanisms driving the differentiation of individuals into distinct castes remain poorly understood, especially for animals forming clonal colonies. We test the association between microbiomes and caste formation within the social trematode Philophthalmus attenuatus, using a metabarcoding approach targeting the bacterial 16S SSU rRNA gene. Clonal colonies of this trematode within snail hosts comprise large reproductive individuals which produce dispersal stages, and small, non-reproducing soldiers which defend the colony against invaders. In colonies extracted directly from field-collected snails, reproductives harboured more diverse bacterial communities than soldiers, and reproductives and soldiers harboured distinct bacterial communities, at all taxonomic levels considered. No single bacterial taxon showed high enough prevalence in either soldiers or reproductives to be singled out as a key driver, indicating that the whole microbial community contributes to these differences. Other colonies were experimentally exposed to antibiotics to alter their bacterial communities, and sampled shortly after treatment and weeks later after allowing for turnover of colony members. At those time points, bacterial communities of the two castes still differed across all antibiotic treatments; however, the caste ratio within colonies changed: after antibiotic disruption and turnover of individuals, new individuals were more likely to become reproductives than in undisturbed control colonies. Our results reveal that each caste has a distinct microbiome; whether the social context affects the microbiota, or whether microbes contribute to modulating the phenotype of individuals, remains to be determined.
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Affiliation(s)
- Fátima Jorge
- Otago Micro and Nano Imaging, Electron Microscopy UnitUniversity of OtagoDunedinNew Zealand
| | - Nolwenn M. Dheilly
- School of Marine and Atmospheric SciencesStony Brook UniversityStony BrookNew YorkUSA,Unité Génétique Virale de Biosécurité, Agence Nationale de Sécurité Sanitaire de l'Alimentation, de l'Environnement et du Travail ‐ Laboratoire de Ploufragan‐PlouzanéANSESPloufraganFrance
| | | | - Robert Poulin
- Department of ZoologyUniversity of OtagoDunedinNew Zealand
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A colony-level optimization model provides a potential mechanism for the evolution of novel castes in eusocial ant colonies. Heliyon 2022; 8:e09882. [PMID: 35815139 PMCID: PMC9260618 DOI: 10.1016/j.heliyon.2022.e09882] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/01/2021] [Accepted: 06/30/2022] [Indexed: 11/23/2022] Open
Abstract
Ant species often have multiple morphologically distinct ‘castes’ within a single colony. Given that most of these castes are involved in non-reproductive tasks, and since such individuals thus never reproduce, the question of how ant castes can evolve is a non-trivial one. Over the years, several models have been proposed in order to explain the evolution of castes in ant colonies. Here, we attempt to answer this question using an economics-based approach, developing an optimization model that implements adaptation and selection at the colony level. We argue that due to the nature of ant colonies, selection is shifted to the group level, and, due to this, individual ants are sheltered from negative selection. We show that our framework can explain the evolution of novel castes in ant colonies, and discuss the novelty of our model with regard to previous models that have been proposed. We also show that our model is consistent with several empirical observations of ant colonies.
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Sabadel AJM, MacLeod CD. Stable isotopes unravel the feeding mode-trophic position relationship in trematode parasites. J Anim Ecol 2021; 91:484-495. [PMID: 34860441 DOI: 10.1111/1365-2656.13644] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 11/15/2021] [Indexed: 11/29/2022]
Abstract
Stable isotopes have been sporadically used over the last two decades to characterise host-parasite trophic relationships. The main reason for this scarcity is the lack of an obvious pattern in the ratio of nitrogen stable isotope values (δ15 N) of parasites in comparison to their host tissues, which would be key to understand any host-parasite system dynamics. To circumvent this, we focused on a single snail host, Zeacumantus subcarinatus, and three of its trematode parasites. We used stable isotopes to investigate each host-trematode trophic relationship and shed light on the mechanisms utilised by the parasite to reroute its hosts' biomass. All our trematodes were found to be 15 N-enriched compared to their host, with their δ15 N values strongly related to their feeding behaviours: passive versus active. It was possible to 'rank' these parasite species and assess their 'relative' trophic position using δ15 N values. We also demonstrated that including a broader range of samples (e.g. host food and faeces, multiple parasite life stages) helped understand the metabolic mechanisms used by the various participants, and that using carbon stable isotope values and C:N ratios allowed to identify an important lipid requirement of these trematode parasites. Finally, we show how critical it is to not ignore parasitic infections as they can have a great influence on their host's trophic position. We have shown that by focussing on a single host species and a single taxonomic group of parasites, we can remove a certain amount of variation recorded by broader isotope studies. We hope that these data will ultimately improve our ability to place parasites in food webs, and thus improve our understanding of the connections and interactions that dictate food web dynamics.
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Affiliation(s)
| | - Colin D MacLeod
- Department of Zoology, University of British Columbia, Vancouver, Canada.,Beaty Biodiversity Museum, University of British Columbia, Vancouver, Canada
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Cribb TH, Cutmore SC, Bray RA. The biodiversity of marine trematodes: then, now and in the future. Int J Parasitol 2021; 51:1085-1097. [PMID: 34757087 DOI: 10.1016/j.ijpara.2021.09.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 09/10/2021] [Accepted: 09/16/2021] [Indexed: 10/19/2022]
Abstract
Trematodes are the richest class of platyhelminths in the marine environment, infecting all classes of marine vertebrates as sexual adults and many phyla of marine invertebrates as part of their life cycles. Despite the cryptic nature of their existence (almost all marine trematodes are internal parasites), they have been the focus of study for almost 250 years, with the first species described in 1774. Here we review progress in the study of the "biodiversity" of these parasites, contrasting the progress made in the last 50 years (post-1971) to that in the almost 200 years before it (pre-1972). We consider an understanding of biodiversity to require knowledge of the species present in the system, an understanding of their evolutionary relationships (which informs higher classification), and, specifically for trematodes, an understanding of their complex life cycles. The fauna is now large, comprising well over 5,000 species. Although species description continues, we see evidence of a slow-down in all aspects of discovery. There has been only one completely new family identified since 1984 and the proposal of new genera is in decline as is the description of new species, especially for those of tetrapods. However, the extent to which this slow-down reflects an approach to the richness asymptote is made uncertain by changes in the field; reduced effort and difficulty of study may be important components of the effect. Regardless of how close we are to a complete description of the fauna, we infer that the outline is well-understood although the details are not. Adoption of molecular methodologies over the last 40 years have complemented morphometric analyses to facilitate objective recognition of species; however, despite these objective data, there is still inconsistency between authors on species delimitation. Molecular methodologies have also completely revolutionised inference of relationships at all levels, from within genera to between orders, and underpinned elucidation of novel life cycles. We expect the next 50 years to produce further dividends from technological innovations. The backdrop to the field will be global environmental concerns and the growing problem of funding for basic biodiversity studies.
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Affiliation(s)
- Thomas H Cribb
- The University of Queensland, School of Biological Sciences, St Lucia, Queensland 4072, Australia.
| | - Scott C Cutmore
- The University of Queensland, School of Biological Sciences, St Lucia, Queensland 4072, Australia
| | - Rodney A Bray
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK
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Mereta ST, Bedewi J, Yewhalaw D, Mandefro B, Abdie Y, Tegegne D, Birke W, Mulat WL, Kloos H. Environmental determinants of distribution of freshwater snails and trematode infection in the Omo Gibe River Basin, southwest Ethiopia. Infect Dis Poverty 2019; 8:93. [PMID: 31744539 PMCID: PMC6865041 DOI: 10.1186/s40249-019-0604-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2019] [Accepted: 11/01/2019] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND Determination of infection rates of snail populations is one of the basic tools for epidemiological studies of snail borne diseases. In this study, we opted to determine the trematode infection of freshwater snails in the Omo-Gibe River Basin, southwest Ethiopia. METHODS We collected snail samples from 130 observation sites in lakes, wetlands, rivers, reservoirs and irrigation canals surveyed during the dry season (March to May) in 2016. The snail samples were examined for trematode infections by cercarial shedding immediately after collection. Habitat conditions, water quality, human water contact practices and other human activities were assessed at each survey site. A redundancy analysis (RDA) was used to examine the relationship between cercarial infection and environmental variables. The statistical significance of eigenvalues and cercariae-environment correlations generated by the RDA were tested using Monte Carlo permutations at 499 permutations. RESULTS A total of 3107 snails belonging to five species were collected. The most abundant species was Biomphalaria pfeifferi, representing 66% of the total collection. Overall, 109 (3.6%) of the snails were found infected with trematodes (cercariae). Biomphalaria pfeifferi was found to be the most highly infected, accounting 85% of all infected snails. A total of eight morphologically different types of cercariae were recorded, which included: Echinostoma cercariae, brevifurcate apharyngeate distome cercariae, amphistome cercariae, brevifurcate apharyngeate monostome cercariae, xiphidiocercariae, longifurcate pharyngeate distome cercariae, strigea cercariae and unidentified cercariae. Brevifurcate apharyngeate distome cercariae, and Echinostoma cercariae were the most abundant cercariae, accounting for 36 and 34% of all infection, respectively. The mean concentration of water conductivity and 5 days biological oxygen demand were higher in irrigation canals and lake sampling points. Human activities such as open field defecation, urination, livestock grazing, farming, and swimming were highly correlated with trematode infection. CONCLUSIONS The abundance, occurrence and infection rates of snail species were largely influenced by water physicochemical quality, sanitation and water contact behaviour of the inhabitants. Human activities, such as open field defecation and urination, livestock grazing, farming, and swimming were important predictors of the abundance of cercariae. Therefore, awareness creation should be implemented for proper containment of excreta (urine and faeces) and reducing human and animal contacts with surface waters to reduce snail-borne disease transmission.
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Affiliation(s)
- Seid Tiku Mereta
- Department of Environmental Health Sciences and Technology, Jimma University, P.O. Box 378, Jimma, Ethiopia
| | - Jemal Bedewi
- Department of Environmental Health Sciences and Technology, Jimma University, P.O. Box 378, Jimma, Ethiopia
| | - Delenasaw Yewhalaw
- Department of Medical Laboratory Sciences & Pathology, Jimma University, P.O. Box 378, Jimma, Ethiopia
| | - Belayhun Mandefro
- Department of Biology, College of Natural and Computational Sciences, Dilla University, P.O. Box 419, Dilla, Ethiopia
| | - Yihun Abdie
- Department of Environmental Health Sciences and Technology, Jimma University, P.O. Box 378, Jimma, Ethiopia
| | - Dechassa Tegegne
- School of Veterinary Medicine, Jimma University, P.O. Box 307, Jimma, Ethiopia
| | - Wondwosen Birke
- Department of Environmental Health Sciences and Technology, Jimma University, P.O. Box 378, Jimma, Ethiopia
| | - Worku Legesse Mulat
- Department of Environmental Health, Wello University, P.O. Box 1145, Dessie, Ethiopia
| | - Helmut Kloos
- Department of Epidemiology and Biostatistics, University of California, San Francisco, USA
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Poulin R, Kamiya T, Lagrue C. Evolution, phylogenetic distribution and functional ecology of division of labour in trematodes. Parasit Vectors 2019; 12:5. [PMID: 30609937 PMCID: PMC6320615 DOI: 10.1186/s13071-018-3241-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/28/2018] [Indexed: 11/13/2022] Open
Abstract
Division of labour has evolved in many social animals where colonies consist of clones or close kin. It involves the performance of different tasks by morphologically distinct castes, leading to increased colony fitness. Recently, a form of division of labour has been discovered in trematodes: clonal rediae inside the snail intermediate host belong either to a large-bodied reproductive caste, or to a much smaller and morphologically distinct ‘soldier’ caste which defends the colony against co-infecting trematodes. We review recent research on this phenomenon, focusing on its phylogenetic distribution, its possible evolutionary origins, and how division of labour functions to allow trematode colonies within their snail host to adjust to threats and changing conditions. To date, division of labour has been documented in 15 species from three families: Himasthlidae, Philophthalmidae and Heterophyidae. Although this list of species is certainly incomplete, the evidence suggests that division of labour has arisen independently more than once in the evolutionary history of trematodes. We propose a simple scenario for the gradual evolution of division of labour in trematodes facing a high risk of competition in a long-lived snail host. Starting with initial conditions prior to the origin of castes (size variation among rediae within a colony, size-dependent production of cercariae by rediae, and a trade-off between cercarial production and other functions, such as defence), maximising colony fitness (R0) can lead to caste formation or the age-structured division of labour observed in some trematodes. Finally, we summarise recent research showing that caste ratios, i.e. relative numbers of reproductive and soldier rediae per colony, become more soldier-biased in colonies exposed to competition from another trematode species sharing the same snail, and also respond to other stressors threatening the host’s survival or the colony itself. In addition, there is evidence of asymmetrical phenotypic plasticity among individual caste members: reproductives can assume defensive functions against competitors in the absence of soldiers, whereas soldiers are incapable of growing into reproductives if the latter’s numbers are reduced. We conclude by highlighting future research directions, and the advantages of trematodes as model systems to study social evolution.
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Affiliation(s)
- Robert Poulin
- Department of Zoology, University of Otago, Dunedin, New Zealand.
| | - Tsukushi Kamiya
- Department of Ecology and Evolutionary Biology, University of Toronto, Toronto, Canada
| | - Clément Lagrue
- Department of Biological Sciences, University of Alberta, Edmonton, Canada
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Lagrue C, MacLeod CD, Keller L, Poulin R. Caste ratio adjustments in response to perceived and realised competition in parasites with division of labour. J Anim Ecol 2018; 87:1429-1439. [DOI: 10.1111/1365-2656.12873] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2017] [Accepted: 05/19/2018] [Indexed: 11/27/2022]
Affiliation(s)
- Clément Lagrue
- Department of Zoology; University of Otago; Dunedin New Zealand
| | - Colin D. MacLeod
- Department of Zoology; University of British Columbia; Vancouver BC Canada
| | - Laurent Keller
- Department of Ecology and Evolution; University of Lausanne; Lausanne Switzerland
| | - Robert Poulin
- Department of Zoology; University of Otago; Dunedin New Zealand
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