Non-coding Regions of Mitochondrial DNA and the cox1 Gene Reveal Genetic Variability Among Local Belarusian Populations of the Causative Agent of Cercarial Dermatitis, Bird Schistosome Trichobilharzia szidati (Digenea: Schistosomatidae)



The cercariae of avian blood flukes Trichobilharzia szidati (Digenea, Schistosomatidae) are known to cause cercarial allergic dermatitis (“swimmer’s itch”) in humans. Global epidemics can have significant impacts on local tourism-related economies in recreational areas. Little is known about the genetic polymorphism of the parasite population, or about the variability of the non-coding regions of mitochondrial DNA (mtDNA) and the possibility of using this as a genetic marker.

Materials and Methods

The T. szidati cercariae were collected over 7 years from 33 naturally infected Lymnaea stagnalis snails from five sites at two neighboring lakes in Belarus. We investigated the variability of the short (SNR) and long (LNR) non-coding regions of mt DNA and the genetic diversity within the 1125-bp sequences of the gene for subunit 1 of cytochrome c oxidase (cox1).


In the SNR sequences, we found only length variability caused by changes in the number of bases in the mononucleotide tracts T6–T8. LNR demonstrates high variability in nucleotide sequence length (182–260 bp) depending on the presence of two long deletions of 59 and 78 nucleotides. Both mitochondrial loci (LNR and cox1) are characterized by high haplotype diversity (H = 0.922 and H = 1.0, respectively); the nucleotide diversity is significantly higher for LNR (π = 1.926 ± 0.443) compared to cox1 (π = 0.704 ± 0.059). Phylogenetic reconstructions based on the variability of each of the loci (LNR and cox1) and their concatenated sequences revealed their shallow structure and the absence of a correlation between the distribution of single-nucleotide polymorphisms and the geographic origin of parasites from two Belarusian lakes. We identified at last four weakly sublineages in the phylogenetic pattern of T. szidati. The carriers of each deletion have specific patterns for each of the two loci and form their own phylogeographic sublineages. An association between two fixed LNR substitutions and a fixed non-synonymous substitution in cox1 was found in four representatives of one lineage that had a short deletion in the LNR.


This study clarified the phylogeographic structure of the Belarusian population of T. szidati. Our data provide the basis for the use two mt markers in large-scale population studies of the parasite, as well as for studying the molecular evolution of coding and non-coding mtDNA in trematodes.

This is a preview of subscription content, access via your institution.

Fig. 1
Fig. 2
Fig. 3


  1. 1.

    Avise JC, Arnold J, Ball RM, Bermingham E, Lamb T, Neigel JE, Reeb CA, Saunders NC (1987) Intraspecific phylogeography: the mitochondrial DNA bridge between population genetics and systematics. Ann Rev Ecol Syst 18:489–522.

    Article  Google Scholar 

  2. 2.

    Ballard JWO, Whitlock MC (2004) The incomplete natural history of mitochondria. Mol Ecol 13:729–744.

    Article  PubMed  Google Scholar 

  3. 3.

    Beer SA, Voronin M (2010) Biology of causative agents of schistosomiasis M: Tovarishchestvo nauchnyh izdanij “KMK”, 200 p/ISBN 978–5–87317–697–7 (In Russian).

  4. 4.

    Brauer A, Kurz A, Stockwell T, Baden-Tillson H, Heidler J, Wittig I, Kauferstein S, Mebs D, Stöcklin R, Remm M (2012) The mitochondrial genome of the venomous cone snail Conus consors. PLoS One 7(12):e51528.

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  5. 5.

    Bronstein O, Kroh A, Haring E (2018) Mind the gap! The mitochondrial control region and its power as a phylogenetic marker in echinoids. BMC Evol Biol 18:80.

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  6. 6.

    Brown WM, George M, Wilson AC (1979) Rapid evolution of animal mitochondrial DNA. Proc Natl Acad Sci 76(4):1967–1971.

    CAS  Article  PubMed  Google Scholar 

  7. 7.

    Chrisanfova GG, Lopatkin AA, Shestak AG, Mischenkov VA, Zhukova TV, Akimova LN, Semyonova SK (2011) Polymorphism of the cox1 mtDNA gene from cercarian isolates of the avian schistosome Bilharziella polonica (Trematoda: Schistosomatidae) from Belarussian lakes. Genetika 47:684–690

    Google Scholar 

  8. 8.

    Clary DO, Wolstenholme DR (1985) The mitochondrial DNA molecule of Drosophila yakuba: nucleotide sequence, gene organization, and genetic code. J Mol Evol 22:252–271.

    CAS  Article  PubMed  Google Scholar 

  9. 9.

    Clement M, Posada D, Crandall KA (2000) TCS: a computer program to estimategene genealogies. Mol Ecol 9: 1657–1660 (

  10. 10.

    De Giorgi C, Martiradonna A, Lanave C, Saccone C (1996) Complete sequence of the mitochondrial DNA in the sea urchin Arbacia lixula: conserved features of the echinoid mitochondrial genome. Mol Phylogenet Evol 5:323–332.

    Article  PubMed  Google Scholar 

  11. 11.

    Dowling DK, Friberg U, Lindell J (2008) Evolutionary implications of non-neutral mitochondrial genetic variation. Trends Ecol Evol 23:546–554

    Article  Google Scholar 

  12. 12.

    Fakhar M, Ghobaditara M, Brant SV, Karamian M, Gohardehi S, Bastani R (2016) Phylogenetic analysis of nasal avian schistosomes (Trichobilharzia) from aquatic birds in Mazandaran Province. northern Iran. Parasitol Int 65:151–158.

    Article  PubMed  Google Scholar 

  13. 13.

    Johnston DA (2006) Genomes and genomics of parasitic flatworms. In: Maule AG, Marks NJ (Eds) Parasitic flatworms: molecular biology, biochemistry, immunology and physiology. CAB International, Wallingford, 2006:37–80.

  14. 14.

    Jouet D, Skirnisson K, Kolarova L, Ferte H (2010) Final hosts and variability of Trichobilharzia regenti under natural conditions. Parasitol Res 107:923–930.

    Article  PubMed  Google Scholar 

  15. 15.

    Horák P, Mikeš L, Lichtenbergová L, Skála V, Soldánová M, Brant SV (2015) Avian schistosomes and outbreaks of cercarial dermatitis. Clin Microbiol Rev 28:165–190.

    Article  PubMed  PubMed Central  Google Scholar 

  16. 16.

    Kheidorova EE (2012) A share of different bird species in functioning of local cercariosis nidus on Lake Naroch and estimation modes of its activity. In: Proceedings of the National Academy of Sciences of Belarus. Biological Series 3:83–87.

  17. 17.

    Korsunenko A, Chrisanfova G, Lopatkin A, Beer SA, Voronin M, Ryskov AP, Semyenova SK (2012) Genetic differentiation of cercariae infrapopulations of the avian schistosome Trichobilharzia szidati based on RAPD markers and mitochondrial cox1 gene. Parasitol Res 110:833–841.

    Article  PubMed  Google Scholar 

  18. 18.

    Kraus RHS, Zeddeman A, van Hooft P, Sartakov D, Soloviev SA, Ydenberg RC, Prins HHT (2011) Evolution and connectivity in the world-wide migration system of the mallard: inferences from mitochondrial DNA. BMC Genet 12:99.

    Article  PubMed  PubMed Central  Google Scholar 

  19. 19.

    Kulikova IV, Drovetski SV, Gibson DD, Harrigan RJ, Rohwer S, Sorenson MD, Winker K, Zhuravlev YN, McCracken KG (2005) Phylogeography of the Mallard (Anas platyrhynchos): Hybridization, dispersal, and lineage sorting contribute to complex geographic structure. Auk 122:949–965.[0949:POTMAP]2.0.CO;2

    Article  Google Scholar 

  20. 20.

    Lockyer AE, Olson PD, Ostergaard P, Rollinson D, Johnston DA, Attwood SW, Southgate VR, Horák P, Snyder SD, Le TH, Agatsuma T, McManus DP, Carmichael AC, Naem S, Littlewood DT (2003) The phylogeny of the Schistosomatidae based on three genes with emphasis on the interrelationships of Schistosoma Weinland, 1858. Parasitology 126(Pt 3):203–224.

    CAS  Article  PubMed  Google Scholar 

  21. 21.

    Lopatkin AA, Khrisanfova GG, Voronin MV, Zazornova OP, Beer SA, Semenova SK (2010) Polymorphism of the cox1 Gene in bird schistosome cercaria isolates (Trematoda, Schistosomatidae) from ponds of Moscow and Moscow oblast. Russ J Genet 46:873–880.

    CAS  Article  Google Scholar 

  22. 22.

    McMillan OW, Palumbi SR (1997) Rapid rate of control-region evolution in Pacific butterflyfishes (Chaetodontidae). J Mol Evol 45:473–484.

    CAS  Article  PubMed  Google Scholar 

  23. 23.

    Mardulyn P, Termonia A, Milinkovitch MC (2003) Structure and evolution of the mitochondrial control region of leaf beetles (Coleoptera: Chrysomelidae): a hierarchical analysis of nucleotide sequence variation. J Mol Evol 56:38–45.

    CAS  Article  PubMed  Google Scholar 

  24. 24.

    Melov S, Hertz GZ, Stormo GD, Johnson TE (1994) Detection of deletions in the mitochondrial genome of Caenorhabditis elegans. Nucl Acids Res 94:1075–1078.

    Article  Google Scholar 

  25. 25.

    Mita S, Rizzuto R, Moraes CT, Shanske S, Arnaudo E, Fabrizi GM, Koga Y, DiMauro S, Schon EA (1990) Recombination via flanking direct repeats is a major cause of large-scale deletions of human mitochondrial DNA. Nucl Acids Res 18:561–567.

    CAS  Article  PubMed  Google Scholar 

  26. 26.

    Moritz C, Dowling TE, Brown WM (1987) Evolution of animal mitochondrial DNA: relevance for population biology and systematics. Annu Rev Ecol Syst 18:269–292.

    Article  Google Scholar 

  27. 27.

    Nadler SA (1995) Microevolution and the genetic structure of parasite populations. J Parasitol 81:395–403 (PMID: 7776124)

    CAS  Article  Google Scholar 

  28. 28.

    Nikiforov M, Pinchuk P, Karlionova N (2013) Belarus on the bird migration routes. Sci Innov 4:20–24

    Google Scholar 

  29. 29.

    Posada D, Crandall KA (2001) Selecting the best-fit model of nucleotide substitution. Syst Biol 50:580–601.

    CAS  Article  PubMed  Google Scholar 

  30. 30.

    Rozas J, Sánchez-DelBarrio JC, Messeguer X, Rozas R (2003) DnaSP, DNA polymorphism analyses by the coalescent and other methods. Bioinformatics 19:2496–2497.

    CAS  Article  PubMed  Google Scholar 

  31. 31.

    Saito S, Tamura K, Aotsuka T (2005) Replication origin of mitochondrial DNA in insects. Genetics 171:1695–1705.

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  32. 32.

    Samuels D, Schon E, Chinnery PF (2004) Two direct repeats cause most human mtDNA deletions. Trends Genet 20:393–398.

    CAS  Article  PubMed  Google Scholar 

  33. 33.

    Semyenova S, Chrisanfova G, Mozharovskaya L, Guliaev A, Ryskov A (2017) The complete mitochondrial genome of the causative agent of the human cercarial dermatitis, the visceral bird schistosome species Trichobilharzia szidati (Platyhelminthes: Trematoda: Schistosomatidae). Mitochondrial DNA Part B 2:469–470.

    Article  PubMed  Google Scholar 

  34. 34.

    Shadel GS, Clayton DA (1997) Mitochondrial DNA maintenance in vertebrates. Annu Rev Biochem 66:409–435.

    CAS  Article  PubMed  Google Scholar 

  35. 35.

    Slatkin M (1985) Rare alleles as indicators of gene flow. Evolution 39:53–65.

    Article  PubMed  Google Scholar 

  36. 36.

    Soldánová M, Selbach C, Sures B, Kostadinova A, Pérez-del-Olmo A (2010) Larval trematode communities in Radix auricularia and Lymnaea stagnalis in a reservoir system of the Ruhr River. Parasit Vectors 3:56–10.

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  37. 37.

    Soldánová M, Selbach C, Kalbe M, Kostadinova A, Sures B (2013) Swimmer’s itch: etiology, impact and risk factors in Europe. Trends Parasitol 29(2):65–74.

    Article  PubMed  Google Scholar 

  38. 38.

    Taanman JW (1999) The mitochondrial genome: structure, transcription, translation and replication. Biochim Biophys Acta 1410(2):103–123.

    CAS  Article  PubMed  Google Scholar 

  39. 39.

    Tamura K, Stecher G, Peterson D, Filipski A, Kumar S (2013) MEGA6: molecular evolutionary genetics analysis version 6.0. Mol Biol Evol 30:2725–2729.

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  40. 40.

    Tajima F (1989) Statistical method for testing the neutral mutation hypothesis by DNA polymorphism. Genetics 123:585–595.

    CAS  Article  PubMed  PubMed Central  Google Scholar 

  41. 41.

    Van Tuyle GC, Gudikote JP, Hurt VR, Miller BB, Moore CA (1996) Multiple, large deletions in rat mitochondrial DNA: evidence for a major hot spot. Mutat Res 349:95–107.

    CAS  Article  PubMed  Google Scholar 

  42. 42.

    Wang X, Liu N (2020) Mitochondrial genome characterization and phylogenetic analysis of bird schistosome Trichobilharzia szidati. Mitochondrial DNA Part B 5(3):2592–2594.

    Article  PubMed  Google Scholar 

  43. 43.

    Watanabe T, Nishida M, Watanabe K, Wewengkang DS, Hidaka M (2005) Polymorphism in nucleotide sequence of mitochondrial intergenic region in Scleractinian Coral (Galaxea fascicularis). Marine Biotech 7:33–39.

    CAS  Article  Google Scholar 

  44. 44.

    Webster BL, Rudolfová J, Horák P, Littlewood DT (2007) The complete mitochondrial genome of the bird schistosome Trichobilharzia regenti (Platyhelminthes: Digenea), causative agent of cercarial dermatitis. J Parasitol 93:553–561.

    CAS  Article  PubMed  Google Scholar 

  45. 45.

    Wolstenholme DR (1992) Animal mitochondrial DNA: structure and evolution. Int Rev Cytol 141:173–216.

    CAS  Article  PubMed  Google Scholar 

  46. 46.

    Xia X, Xie Z (2001) DAMBE: Software package for data analysis in molecular biology and evolution. J Hered 92:371–373.

    CAS  Article  PubMed  Google Scholar 

  47. 47.

    Yui R, Matsuura ET (2006) Detection of deletions flanked by short direct repeats in mitochondrial DNA of aging Drosophila. Mutat Res 594:155–161.

    CAS  Article  PubMed  Google Scholar 

  48. 48.

    Zhang DX, Hewitt GM (1997) Insect mitochondrial control region: a review of its structure, evolution and usefulness in evolutionary studies. Biochem Syst Ecol 25:99–120.

    Article  Google Scholar 

Download references


We would thank the anonymous reviewers for providing valuable comments on the manuscript. This study was performed using the equipment of IGB RAS core facilities and partly supported by the Russian Science Foundation No. 18-04-01047 and the RAS Program Molecular and Cell Biology. The study was carried out in the framework with the Decree of the President of the Republic of Belarus from February 14, 2005, No. 71 “On the State Program for the Ecological Improvement of Lake Naroch for 2005-2008” (Registered in the National Register of Legal Acts of the Republic of Belarus on February 15, 2005 No. 1/6237).

Author information




GC, LM, and TZ carried out the experiment. GC, SS, and DN contributed to the design and implementation of the research. SS and GC wrote the manuscript. All authors provided critical feedback and helped shape the research, analysis, and manuscript.

Corresponding author

Correspondence to Seraphima Semyenova.

Ethics declarations

Conflict of interest

The authors report that they have no conflict of interest. The authors alone are responsible for the content and writing of the article.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Chrisanfova, G., Mozharovskaya, L., Zhukova, T. et al. Non-coding Regions of Mitochondrial DNA and the cox1 Gene Reveal Genetic Variability Among Local Belarusian Populations of the Causative Agent of Cercarial Dermatitis, Bird Schistosome Trichobilharzia szidati (Digenea: Schistosomatidae). Acta Parasit. (2021).

Download citation


  • Trematoda
  • Mitochondrial DNA
  • Non-coding region
  • Cox1∙population
  • Trichobilharzia szidati