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Courtot É, Boisseau M, Dhorne-Pollet S, Serreau D, Gesbert A, Reigner F, Basiaga M, Kuzmina T, Lluch J, Annonay G, Kuchly C, Diekmann I, Krücken J, von Samson-Himmelstjerna G, Mach N, Sallé G. Comparison of two molecular barcodes for the study of equine strongylid communities with amplicon sequencing. PeerJ 2023; 11:e15124. [PMID: 37070089 PMCID: PMC10105562 DOI: 10.7717/peerj.15124] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Accepted: 03/03/2023] [Indexed: 04/19/2023] Open
Abstract
Basic knowledge on the biology and epidemiology of equine strongylid species still needs to be improved to contribute to the design of better parasite control strategies. Nemabiome metabarcoding is a convenient tool to quantify and identify species in bulk samples that could overcome the hurdle that cyathostomin morphological identification represents. To date, this approach has relied on the internal transcribed spacer 2 (ITS-2) of the ribosomal RNA gene, with a limited investigation of its predictive performance for cyathostomin communities. Using DNA pools of single cyathostomin worms, this study aimed to provide the first elements to compare performances of the ITS-2 and a cytochrome c oxidase subunit I (COI) barcode newly developed in this study. Barcode predictive abilities were compared across various mock community compositions of two, five and 11 individuals from distinct species. The amplification bias of each barcode was estimated. Results were also compared between various types of biological samples, i.e., eggs, infective larvae or adults. Bioinformatic parameters were chosen to yield the closest representation of the cyathostomin community for each barcode, underscoring the need for communities of known composition for metabarcoding purposes. Overall, the proposed COI barcode was suboptimal relative to the ITS-2 rDNA region, because of PCR amplification biases, reduced sensitivity and higher divergence from the expected community composition. Metabarcoding yielded consistent community composition across the three sample types. However, imperfect correlations were found between relative abundances from infective larvae and other life-stages for Cylicostephanus species using the ITS-2 barcode. While the results remain limited by the considered biological material, they suggest that additional improvements are needed for both the ITS-2 and COI barcodes.
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Affiliation(s)
- Élise Courtot
- Animal Health, UMR1282 Infectiologie et Santé Publique, INRAE, Nouzilly, France
| | - Michel Boisseau
- Animal Health, UMR1282 Infectiologie et Santé Publique, INRAE, Nouzilly, France
- Animal Health, UMR1225 IHAP, Institut National de la Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Toulouse, France
| | | | - Delphine Serreau
- Animal Health, UMR1282 Infectiologie et Santé Publique, INRAE, Nouzilly, France
| | - Amandine Gesbert
- Animal Physiology, UEPAO, Institut National de la Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Nouzilly, France
| | - Fabrice Reigner
- Animal Physiology, UEPAO, Institut National de la Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Nouzilly, France
| | | | - Tetiana Kuzmina
- Schmalhausen Institute of Zoology NAS of Ukraine, Kyiv, Ukraine
- Institute of Parasitology, Slovak Academy of Sciences, Košice, Slovak Republic
| | - Jérôme Lluch
- GeT-PlaGe, Institut National de la Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Toulouse, France
| | - Gwenolah Annonay
- GeT-PlaGe, Institut National de la Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Toulouse, France
| | - Claire Kuchly
- GeT-PlaGe, Institut National de la Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Toulouse, France
| | - Irina Diekmann
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Jürgen Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | | | - Nuria Mach
- Animal Health, UMR1225 IHAP, Institut National de la Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Toulouse, France
| | - Guillaume Sallé
- Animal Health, UMR1282 Infectiologie et Santé Publique, INRAE, Nouzilly, France
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Sargison N, Chambers A, Chaudhry U, Costa Júnior L, Doyle SR, Ehimiyein A, Evans M, Jennings A, Kelly R, Sargison F, Sinclair M, Zahid O. Faecal egg counts and nemabiome metabarcoding highlight the genomic complexity of equine cyathostomin communities and provide insight into their dynamics in a Scottish native pony herd. Int J Parasitol 2022; 52:763-774. [PMID: 36208676 DOI: 10.1016/j.ijpara.2022.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2022] [Revised: 08/16/2022] [Accepted: 08/21/2022] [Indexed: 11/05/2022]
Abstract
Understanding the composition of gastrointestinal nematode communities may help to mitigate or exploit parasite adaptations within their host. We have used nemabiome deep amplicon sequencing of internal transcribed spacer-2 (ITS-2) ribosomal DNA to describe the temporal and host species composition of gastrointestinal nematode communities following sampling of six Scottish ponies across 57 months. In the absence of parasite control, each horse showed seasonal trends of increases and decreases in faecal egg counts, consistent with the epidemiology of equine strongylid parasites, however, the composition of parasites within individuals changed over time. Sixteen presumptive strongylid species were identified in each of the horses, 13 of which were distributed in a complex clade together with small numbers of amplicon sequences which could not be classified beyond the Cyathostominae subfamily level. Egg shedding of seven trichostrongylid species, which had previously been identified in co-grazed Soay sheep, was identified during the early spring. Faecal egg counts and the percentage of amplicon sequences assigned to each gastrointestinal nematode species were combined to describe their relative abundance across both host and time. Significant differences in species diversity between horses and between months were observed, being greatest from March to May and least from October to December. The magnitude of the individual horse effect varied between months and, conversely, the magnitude of the seasonal effect varied between individual horses. The most abundant gastrointestinal nematode in each of the horses was Cylicostephanus longibursatus (46.6% overall), while the abundance of the other strongylid species varied between horses and relative to each other. Patent C. longibursatus infections over the winter months might represent a genetic adaptation towards longer adult worm survival, or a lower rate of developmental arrest in the autumn. This study provides insight into highly complex phylogenetic relationships between closely related cyathostomin species; and describes the dynamics of egg shedding and pasture contamination of co-infecting equine gastrointestinal nematode communities. The results could be applied to determine how climatic and management factors affect the equilibrium between hosts and their parasites, and to inform the development of sustainable gastrointestinal nematode control strategies for different host species.
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Affiliation(s)
- Neil Sargison
- University of Edinburgh, Royal (Dick) School of Veterinary Studies and The Roslin Institute, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG, UK.
| | - Alex Chambers
- University of Edinburgh, Royal (Dick) School of Veterinary Studies and The Roslin Institute, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG, UK
| | - Umer Chaudhry
- University of Edinburgh, Royal (Dick) School of Veterinary Studies and The Roslin Institute, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG, UK
| | - Livio Costa Júnior
- Federal University of Maranhão, Pathology Department, São Luís, Maranhão, Brazil
| | - Stephen R Doyle
- Wellcome Sanger Institute, Wellcome Genome Campus, Hinxton, Cambridge CB10 1SA, UK
| | - Ajoke Ehimiyein
- University of Edinburgh, Royal (Dick) School of Veterinary Studies and The Roslin Institute, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG, UK
| | - Mike Evans
- University of Edinburgh, Royal (Dick) School of Veterinary Studies and The Roslin Institute, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG, UK
| | - Amy Jennings
- University of Edinburgh, Royal (Dick) School of Veterinary Studies and The Roslin Institute, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG, UK
| | - Rob Kelly
- University of Edinburgh, Royal (Dick) School of Veterinary Studies and The Roslin Institute, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG, UK
| | - Fiona Sargison
- University of Edinburgh, Royal (Dick) School of Veterinary Studies and The Roslin Institute, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG, UK
| | | | - Osama Zahid
- University of Edinburgh, Royal (Dick) School of Veterinary Studies and The Roslin Institute, Easter Bush Veterinary Centre, Roslin, Midlothian EH25 9RG, UK
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Effect of sainfoin ( Onobrychis viciifolia) on cyathostomin eggs excretion, larval development, larval community structure, and efficacy of ivermectin treatment in horses. Parasitology 2022; 149:1439-1449. [PMID: 35929352 PMCID: PMC10090777 DOI: 10.1017/s0031182022000853] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Alternative strategies to chemical anthelmintics are needed for the sustainable control of equine strongylids. Bioactive forages like sainfoin (Onobrychis viciifolia) could contribute to reducing drug use, with the first hints of in vitro activity against cyathostomin free-living stages observed in the past. We analysed the effect of a sainfoin-rich diet on cyathostomin population and the efficacy of oral ivermectin treatment. Two groups of 10 naturally infected horses were enrolled in a 78-day experimental trial. Following a 1-week adaptation period, they were either fed with dehydrated sainfoin pellets (70% of their diet dry matter) or with alfalfa pellets (control group) for 21-days. No difference was found between the average fecal egg counts (FECs) of the two groups, but a significantly lower increase in larval development rate was observed for the sainfoin group, at the end of the trial. Quantification of cyathostomin species abundances with an ITS-2-based metabarcoding approach revealed that the sainfoin diet did not affect the nemabiome structure compared to the control diet. Following oral ivermectin treatment of all horses on day 21, the drug concentration was lower in horses fed with sainfoin, and cyathostomin eggs reappeared earlier in that group. Our results demonstrated that short-term consumption of a sainfoin-rich diet does not decrease cyathostomin FEC but seems to slightly reduce larval development. Consumption of dehydrated sainfoin pellets also negatively affected ivermectin pharmacokinetics, underscoring the need to monitor horse feeding regimes when assessing ivermectin efficacy in the field.
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Tombak KJ, Hansen CB, Kinsella JM, Pansu J, Pringle RM, Rubenstein DI. The gastrointestinal nematodes of plains and Grevy's zebras: Phylogenetic relationships and host specificity. Int J Parasitol Parasites Wildl 2021; 16:228-235. [PMID: 34712556 PMCID: PMC8529100 DOI: 10.1016/j.ijppaw.2021.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 10/11/2021] [Accepted: 10/11/2021] [Indexed: 01/08/2023]
Abstract
Equids are chronically infected with parasitic strongyle nematodes. There is a rich literature on horse strongyles, but they are difficult to identify morphologically and genetic studies on strongyles infecting other equid species are few, hampering studies of host specificity. We sequenced expelled worms from two sympatric zebra species in central Kenya to expand the strongyle phylogeny and used DNA metabarcoding on faecal samples to genetically characterize zebra nemabiomes for the first time. We generated sequences for several species new to public genetic reference databases, all of which are typical strongyles in wild zebras (i.e., the three species of Cylindropharynx and Cyathostomum montgomeryi), and identified their closest relatives. We also discovered an apparent fungus infecting a quarter of the expelled Crossocephalus viviparus worms, a hyperabundant nematode species in the family Atractidae, hinting at the possibility that zebra host-parasite dynamics may involve a zebra-fungus mutualism. The two zebra species had similar nemabiomes; we found a complete overlap in the list of nematode species they carry and very similar prevalence (i.e., proportion of hosts infected) for the different nematode species. Our study suggests limited host-specificity in zebra strongyles and high potential for transmission between the plains zebra and the endangered Grevy's zebra.
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Affiliation(s)
- Kaia J. Tombak
- Department of Ecology and Evolutionary Biology, Princeton University, Guyot Hall, Princeton, NJ, USA, 08544
- Department of Anthropology, Hunter College of the City University of New York, 695 Park Ave, New York, NY, USA, 10065
- Corresponding author. Department of Anthropology, Hunter College of the City University of New York, 695 Park Ave, New York, NY, 10065, USA.
| | - Christina B. Hansen
- Department of Ecology and Evolutionary Biology, Princeton University, Guyot Hall, Princeton, NJ, USA, 08544
| | | | - Johan Pansu
- Department of Ecology and Evolutionary Biology, Princeton University, Guyot Hall, Princeton, NJ, USA, 08544
- ISEM, Université de Montpellier, CNRS, IRD, EPHE, Montpellier, France
| | - Robert M. Pringle
- Department of Ecology and Evolutionary Biology, Princeton University, Guyot Hall, Princeton, NJ, USA, 08544
| | - Daniel I. Rubenstein
- Department of Ecology and Evolutionary Biology, Princeton University, Guyot Hall, Princeton, NJ, USA, 08544
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5
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Krücken J, Czirják GÁ, Ramünke S, Serocki M, Heinrich SK, Melzheimer J, Costa MC, Hofer H, Aschenborn OHK, Barker NA, Capodanno S, de Carvalho LM, von Samson-Himmelstjerna G, East ML, Wachter B. Genetic diversity of vector-borne pathogens in spotted and brown hyenas from Namibia and Tanzania relates to ecological conditions rather than host taxonomy. Parasit Vectors 2021; 14:328. [PMID: 34134753 PMCID: PMC8207800 DOI: 10.1186/s13071-021-04835-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2021] [Accepted: 06/09/2021] [Indexed: 11/23/2022] Open
Abstract
Background Improved knowledge on vector-borne pathogens in wildlife will help determine their effect on host species at the population and individual level and whether these are affected by anthropogenic factors such as global climate change and landscape changes. Here, samples from brown hyenas (Parahyaena brunnea) from Namibia (BHNA) and spotted hyenas (Crocuta crocuta) from Namibia (SHNA) and Tanzania (SHTZ) were screened for vector-borne pathogens to assess the frequency and genetic diversity of pathogens and the effect of ecological conditions and host taxonomy on this diversity. Methods Tissue samples from BHNA (n = 17), SHNA (n = 19) and SHTZ (n = 25) were analysed by PCRs targeting Anaplasmataceae, Rickettsia spp., piroplasms, specifically Babesia lengau-like piroplasms, Hepatozoidae and filarioids. After sequencing, maximum-likelihood phylogenetic analyses were conducted. Results The relative frequency of Anaplasmataceae was significantly higher in BHNA (82.4%) and SHNA (100.0%) than in SHTZ (32.0%). Only Anaplasma phagocytophilum/platys-like and Anaplasma bovis-like sequences were detected. Rickettsia raoultii was found in one BHNA and three SHTZ. This is the first report of R. raoultii from sub-Saharan Africa. Babesia lengau-like piroplasms were found in 70.6% of BHNA, 88.9% of SHNA and 32.0% of SHTZ, showing higher sequence diversity than B. lengau from South African cheetahs (Acinonyx jubatus). In one SHTZ, a Babesia vogeli-like sequence was identified. Hepatozoon felis-like parasites were identified in 64.7% of BHNA, 36.8% of SHNA and 44.0% of SHTZ. Phylogenetic analysis placed the sequences outside the major H. felis cluster originating from wild and domestic felids. Filarioids were detected in 47.1% of BHNA, 47.4% of SHNA and 36.0% of SHTZ. Phylogenetic analysis revealed high genetic diversity and suggested the presence of several undescribed species. Co-infections were frequently detected in SHNA and BHNA (BHNA median 3 pathogens, range 1–4; SHNA median 3 pathogens, range 2–4) and significantly rarer in SHTZ (median 1, range 0–4, 9 individuals uninfected). Conclusions The frequencies of all pathogens groups were high, and except for Rickettsia, multiple species and genotypes were identified for each pathogen group. Ecological conditions explained pathogen identity and diversity better than host taxonomy. Graphic Abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-021-04835-x.
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Affiliation(s)
- Jürgen Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
| | - Gábor Á Czirják
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Sabrina Ramünke
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Maria Serocki
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany.,Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Sonja K Heinrich
- Department of Wildlife Diseases, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany.,Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Jörg Melzheimer
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - M Carolina Costa
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.,Centro de Investigação Interdisciplinar Em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisbon, Portugal
| | - Heribert Hofer
- Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany.,Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.,Department of Biology, Freie Universität Berlin, Berlin, Germany
| | | | - Nancy A Barker
- School of Life Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Stefano Capodanno
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.,Department of Veterinary Medicine, University Federico II of Naples, Naples, Italy
| | - Luís Madeira de Carvalho
- Centro de Investigação Interdisciplinar Em Sanidade Animal, Faculdade de Medicina Veterinária, Universidade de Lisboa, Lisbon, Portugal
| | | | - Marion L East
- Department of Ecological Dynamics, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
| | - Bettina Wachter
- Department of Evolutionary Ecology, Leibniz Institute for Zoo and Wildlife Research, Berlin, Germany
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Louro M, Kuzmina TA, Bredtmann CM, Diekmann I, de Carvalho LMM, von Samson-Himmelstjerna G, Krücken J. Genetic variability, cryptic species and phylogenetic relationship of six cyathostomin species based on mitochondrial and nuclear sequences. Sci Rep 2021; 11:8245. [PMID: 33859247 PMCID: PMC8050097 DOI: 10.1038/s41598-021-87500-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Accepted: 03/30/2021] [Indexed: 11/23/2022] Open
Abstract
Cyathostomins are important intestinal nematode parasites of equines and include 50 accepted species. Their taxonomy has been frequently revised and the presence of cryptic species suggested. Furthermore, usually molecular- and morphology-based phylogenetic analyses give divergent results. In this study, the nucleotide sequences of the nuclear second internal transcribed spacer (ITS-2) and the mitochondrial partial cytochrome c oxidase subunit I (COI) were determined for adults of six cyathostomin species (Coronocyclus coronatus, Coronocyclus labiatus, Cylicocyclus nassatus, Cylicostephanus calicatus, Cylicostephanus longibursatus, Cylicostephanus minutus) collected from different equine species within two geographic regions. Maximum likelihood trees were calculated for ITS-2, COI, and concatenated data. No obvious differentiation was observed between geographic regions or equine host species. As previously reported, Coronocyclus coronatus and Cylicostephanus calicatus revealed a close relationship. Cryptic species were detected in Cylicostephanus minutus and Cylicostephanus calicatus. Cylicocyclus nassatus and Coronocyclus labiatus showed diverse mitochondrial and nuclear haplotypes occurring in different combinations, while Cylicostephanus longibursatus was comparatively homogenous. In conclusion, a combined analysis of nuclear and mitochondrial haplotypes improved resolution of the phylogeny and should be applied to the remaining cyathostomin species and across additional equine host species and geographic regions.
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Affiliation(s)
- Mariana Louro
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
| | - Tetiana A Kuzmina
- I. I. Schmalhausen Institute of Zoology, National Academy of Sciences of Ukraine, Kyiv, Ukraine
| | - Christina M Bredtmann
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Irina Diekmann
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Luís M Madeira de Carvalho
- CIISA - Centre for Interdisciplinary Research in Animal Health, Faculty of Veterinary Medicine, University of Lisbon, Lisbon, Portugal
| | - Georg von Samson-Himmelstjerna
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Jürgen Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Department of Veterinary Medicine, Freie Universität Berlin, Berlin, Germany.
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Kuchboev A, Sobirova K, Karimova R, Amirov O, von Samson-Himmelstjerna G, Krücken J. Molecular analysis of polymorphic species of the genus Marshallagia (Nematoda: Ostertagiinae). Parasit Vectors 2020; 13:411. [PMID: 32787940 PMCID: PMC7425555 DOI: 10.1186/s13071-020-04265-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 07/29/2020] [Indexed: 12/05/2022] Open
Abstract
Background The genus Marshallagia (Family Haemonchidae, subfamily Ostertagiinae) contains multiple species of nematodes parasitising the abomasum (or duodenum) of ruminants, in particular of Caprinae. Male specimens have been described to be polymorphic with the frequent/major morphotype initially described in the genus Marshallagia while the minor/rare morphotype was initially often placed in the genus Grossospicularia. Due to common morphological features, certain pairs of morphotypes were suggested to belong to the same species such as Marshallagia marshalli/M. occidentalis. However, molecular evidence to confirm these pairs of morphotypes belonging to the same species is missing. Methods In the present study, Marshallagia sp. were collected from domestic sheep in Uzbekistan. Male specimens were morphologically described with particular emphasis on the structure of the bursa copulatrix. After DNA isolation from morphologically identified specimens, PCRs targeting the ribosomal internal transcribed spacer 2 (ITS2) and mitochondrial cytochrome c oxidase subunit 1 (cox1) regions were conducted. After Sanger sequencing, maximum likelihood phylogenetic analyses and pairwise identities between sequences were calculated. Results The major morphotypes of M. marshalli, M. schumakovitschi and M. uzbekistanica and the minor morphotypes M. occidentalis, M. trifida and M. sogdiana were identified and their morphology was documented in detail. ITS2 sequences showed little variation and did not allow diagnosing species. In contrast, phylogenetic analysis of cox1 sequences identified highly supported clusters and verified that M. marshalli, M. occidentalis and M. uzbekistanica are different morphotypes of the species M. marshalli while M. schumakovitschi and M. trifida represent distinct morphotypes of M. trifida. For M. sogdiana no corresponding major morphotype could be identified in the present study. Due to a large barcoding gap, comparison of cox1 sequences in terms of percent identity was sufficient to reliably assign the sequences to a particular species without phylogenetic analysis. Conclusions The data presented here create a framework that will allow the classification of other members of the genus in the future and underline that parallel morphological and molecular analysis of specimens is crucial to improve the taxonomy of polymorphic species.![]()
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Affiliation(s)
- Abdurakhim Kuchboev
- Institute of Zoology, Uzbekistan Academy of Sciences, Bogishamol str. 232B, Tashkent, 100053, Uzbekistan
| | - Khanifakhon Sobirova
- Institute of Zoology, Uzbekistan Academy of Sciences, Bogishamol str. 232B, Tashkent, 100053, Uzbekistan
| | - Rokhatoy Karimova
- Institute of Zoology, Uzbekistan Academy of Sciences, Bogishamol str. 232B, Tashkent, 100053, Uzbekistan
| | - Oybek Amirov
- Institute of Zoology, Uzbekistan Academy of Sciences, Bogishamol str. 232B, Tashkent, 100053, Uzbekistan
| | - Georg von Samson-Himmelstjerna
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany
| | - Jürgen Krücken
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Robert-von-Ostertag-Str. 7-13, 14163, Berlin, Germany.
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