Original Article

The Larval Stages of Echinostoma spp. in Freshwater Snails as the First and Second Intermediate Hosts in Gilan and Mazandaran Provinces, Northern Iran


Background: Identification of the larval stages of Echinostoma spp. in freshwater snails is an essential guide to continue monitoring the possibility of their transmission and the potential of echinostomiasis in areas where trematodes are the primary agent of parasitic diseases. The aim of this study was investigate Echinostoma using morphological and molecular techniques.Methods: The study was conducted in Gilan and Mazandaran Provinces, northern Iran, from April 2019 to October 2021. Overall, 5300 freshwater snails were randomly collected and were identified using external shell morphology. Meanwhile, snails infected with trematodes were studied via shedding and dissecting methods. Larvae stages of Echinostoma were identified and the genomic DNA of the samples was extracted. The PCR amplification of the ITSI gene was carried out for 17 isolates and products were sequenced. Seven sequences were deposited in GenBank.Results: Totally, 3.5% of snails containing three species (Stagnicola sp., Radix sp. and Planorbis sp.) were infected with two types of cercaria, E. revolutum with 37 and Echinostoma sp. with 45 spines in the collar. Moreover, 35% of the snails were infected with Echinostoma spp. metacercaria. Phylogenetic analysis illustrated that isolates were included in two ITSI haplogroups. Conclusion: Results showed the potential hazard of a zoonotic parasite as Echinostoma in northern Iran. The potential of disease environmental relationship investigation and resource control optimization is necessary for effective disease prevention and health management.

1. Toledo R, Esteban J. An update on human echinostomiasis. Trans R Soc Trop Med Hyg. 2016;110(1):37-45.
2. Chai J-Y. Human intestinal flukes. Springer; 2019.
3. Soldánová M, Selbach C, Sures B, Kostadinova A, Pérez-del-Olmo A. Larval trematode communities in Radix auricularia and Lymnaea stagnalis in a reservoir system of the ruhr river. Parasit Vectors. 2010;3:56.
4. Faltýnková A, Našincová V, Kablásková L. Larval trematodes (digenea) of planorbid snails (gastropoda: Pulmonata) in central europe: A survey of species and key to their identification. Syst. Parasitol. 2008;69(3):155-178.
5. Ewens W.J, Warren J, Fried B, Toledo R. The Biology of Echinostomes: From the Molecule to the Community. 2009. Springer New York.
6. Owiny MO, Obonyo MO, Gatongi PM, Fèvre EM. Prevalence and spatial distribution of trematode cercariae in vector snails within different agro-ecological zones in western kenya, 2016. Pan Afr Med J. 2019;32:142.
7. Routtu J, Grunberg D, Izhar R,et al. Selective and universal primers for trematode barcoding in freshwater snails. Parasitol Res. 2014;113(7):2535-2540.
8. Aryaiepour M, Mansoorian AB, Rad MBM,et al. Contamination of vector snails with the larval stages of trematodes in selected areas in northern iran. Iran J Public Health. 2022;51(6):1400-1410.
9. Olivier L, Schneiderman M. A method for estimating the density of aquatic snail populations. Exp Parasitol. 1956;5(2):109-117.
10. Glöer P, Pešić V. The freshwater snails (gastropoda) of Iran, with descriptions of two new genera and eight new species. ZooKeys. 2012:11-61.
11. Yamaguti, Satyu. A Synoptical Review of Life Histories of Digenetic Trematodes of Vertebrates : with Special Reference to the Morphology of Their Larval Forms. [S.l.]: Yugaku -sha , 1975.
12. Ataev GL, Dobrovolskij AA, Fournier A, Jourdane J. Migration and development of mother sporocysts of Echinostoma caproni (digenea: Echinostomatidae). J Parasitol. 1997;83(3):444-453.
13. Aryaeipour M, Rouhani S, Bandehpour M, Mirahmadi H, Kazemi B, Rokni MB. Genotyping and phylogenetic analysis of Fasciola spp. Isolated from sheep and cattle using pcr-rflp in ardabil province, northwestern IRAN. Iran J Public Health. 2014; 43(10): 1364-1371.
14. Alizadeh G, Aryaeipour M, Mohebali M, Mowlavi GR, Raissi V, Rokni MB. Evaluation of semi-nested pcr compared with indirect-elisa to diagnose human fasciolosis. Iran J Public Health. 2022;51(3):686-694.
15. Kumar S, Stecher G, Li M, Knyaz C, Tamura K. Mega x: Molecular evolutionary genetics analysis across computing platforms. Mol Biol Evol. 2018; 35(6):1547-1549.
16. Saitou N, Nei M. The neighbor-joining method: A new method for reconstructing phylogenetic trees. Mol Biol Evol. 1987;4(4):406-425.
17. Shimodaira H, Hasegawa M. Consel: For assessing the confidence of phylogenetic tree selection. Bioinformatics. 2001;17(12):1246-1247.
18. Tamura K, Nei M. Estimation of the number of nucleotide substitutions in the control region of mitochondrial DNA in humans and chimpanzees. Mol Biol Evol. 1993;10(3):512-526.
19. Bandelt H-J, Forster P, Röhl A. Median-joining networks for inferring intraspecific phylogenies. Mol Biol Evol. 1999;16(1):37-48.
20. Faltýnková A, Našincová V, Kablásková L. Larval trematodes (digenea) of the great pond snail, Lymnaea stagnalis (l.),(gastropoda, pulmonata) in central europe: A survey of species and key to their identification. Parasite. 2007;14(1):39-51.
21. Bozorgomid A, Rouhani S, Harandi MF, Ichikawa-Seki M, Raeghi S. Genetic diversity and distribution of Fasciola hepatica haplotypes in Iran: Molecular and phylogenetic studies. Vet Parasitol Reg Stud Reports. 2020;19:100359.
22. Sah R, Khadka S, Hamal R, Poudyal S. Human echinostomiasis: A case report. BMC Res Notes. 2018;11(1):17.
23. Khanna V, Tilak K, Mukim Y, Khanna R. An unusual case of echinostomiasis in a retropositive patient: A case report. Hum Parasit Dis. 2016;8:43.
24. Khanna V, Ashraf AA, Khanna R. Echinostomiasis in a child with severe anemia. Trop Parasitol. 2019;9(1):54-56.
25. Graczyk TK, Fried B. Echinostomiasis: A common but forgotten food-borne disease. Am J Trop Med Hyg. 1998;58(4):501-504.
26. Ahmadi M, Beigom Kia E, Rezaeian M, Hosseini M, Kamranrashani B, Tarighi F. Prevalence of strongyloides stercoralis and other intestinal parasites in rehabilitation centers in mazandaran province, northern iran. Journal of Mazandaran University of Medical Sciences. 2015;25:1-7.
27. Aryaeipour M, Kia EB, Heidari Z, Talaie ZS, Rokni MB. Serological study of human fasciolosis in patients referring to the school of public health, Tehran University of Medical Sciences, Tehran, Iran during 2008–2014. Iran J Parasitol. 2015;10(4):517-522.
28. Hosseini-Safa A, Rokni MB, Mosawi SH, et al. High-resolution melting analysis as an appropriate method to differentiate between fasciola hepatica and F. Gigantica. Iran J Public Health. 2019;48(3):501-507.
29. Chantima K, Suk-Ueng K, Kampan M. Freshwater snail diversity in mae lao agricultural basin (Chiang Rai, Thailand) with a focus on larval trematode infections. Korean J Parasitol. 2018;56(3):247-257.
30. Anucherngchai S, Tejangkura T, Chontananarth T. Epidemiological situation and molecular identification of cercarial stage in freshwater snails in chao-phraya basin, central Thailand. Asian Pac J Trop Biomed. 2016;6:539-545.
31. Krailas D, Namchote S, Koonchornboon T, Dechruksa W, Boonmekam D. Trematodes obtained from the Thiarid freshwater snail melanoides tuberculata (müller, 1774) as vector of human infections in Thailand. Zoosyst Evol. 2014;90:57.
32. Salahi-Moghaddam A, Mahvi AH, Mowlavi G, Hoseini-Chegini A, Massoud J. Parasitological study on Lymnaea palustris and its ecological survey by gis in mazandaran province. Pathobiol Res. 2009;11:65-71.
33. Sharif M, Daryani A, Karimi S. A faunistic survey of cercariae isolated from lymnaeid snails in. Pak J Biol Sci. 2010;13(4):158-163.
34. Yamaguti S. Synopsis of digenetic trematodes of vertebrates. Vols I and II. 1971. Keigaku Publishing Co.
35. Ataev GL, Coustau C. Cellular response to echinostoma caproni infection in Biomphalaria glabrata strains selected for susceptibility/resistance. Dev Comp Immunol. 1999;23(3):187-198.
36. Chantima K, Chai J-Y, Wongsawad C. Echinostoma revolutum: Freshwater snails as the second intermediate hosts in chiang mai, Thailand. Korean J Parasitol. 2013;51(2):183-189.
37. Georgieva S, Selbach C, Faltýnková A, et al. New cryptic species of the ‘revolutum’group of echinostoma (digenea: Echinostomatidae) revealed by molecular and morphological data. Parasit Vectors. 2013;6:64.
38. ImaniBaran A. Survey of population changes and cercarial infection of lymnaea spp freshwater snails. In Miyandoab region, west azarbaijan province in 2010. Journal of Rafsanjan University of Medical Sciences. 2014;13:581-596.
39. Xiao X, Lu D, Wang T,et al. Studies on mode of human infection with Echinochasmus liliputanus. Zhongguo Ji Sheng Chong Xue Yu Ji Sheng Chong Bing Za Zhi= Chinese journal of parasitology and parasitic diseases. 1995;13(3):197-199.
40. Chai JY, Sohn WM, Na BK, Van De N. Echinostoma revolutum: Metacercariae in Filopaludina snails from Nam Dinh Province, Vietnam and adults from experimental hamsters. Korean J Parasitol. 2011;49(4):449-455.
41. Tenorio JCB, Molina EC. Monsters in our food: Foodborne trematodiasis in the philippines and beyond. Veterinary Integrative Sciences. 2021;19:467-485.
42. Haveland-Smith R, Combes R. Screening of food dyes for genotoxic activity. Food Cosmet Toxicol. 1980;18(3):215-221.
IssueVol 18 No 2 (2023) QRcode
SectionOriginal Article(s)
DOI https://doi.org/10.18502/ijpa.v18i2.13184
Echinostoma Cercaria Metacercaria Freshwater snail Iran

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How to Cite
Aryaiepour M, Mazaheri Nezhad Fard R, Molai Rad MB, Pirestani M, Rouhani S, Daryani A, Asadi T, Sarvi S, Rokni MB. The Larval Stages of Echinostoma spp. in Freshwater Snails as the First and Second Intermediate Hosts in Gilan and Mazandaran Provinces, Northern Iran. Iran J Parasitol. 2023;18(2):182-192.