• Logo
  • SBMUJournals

Prevalence and Subtype Identification of Blastocystis Isolated from Humans in Ahvaz, Southwestern Iran

Roya Salehi, Ali Haghighi, C. Rune Stensvold, Farnaz Kheirandish, Eznelloah Azargashb, Saber Raeghi, Kobra Kohansal, Fares Bahrami




Aim: The aim of the present study was to determine the prevalence and subtype distribution of Blastocystis and its relation with demographic data and symptoms in humans referred to medical centers in Ahvaz 2014-2015.

Background: Infections with intestinal parasites are one of the most important threats to human health worldwide, especially in tropical and subtropical areas. Blastocystis sp. is a common parasite of humans with a vast variety of non-human hosts. We aimed to study the prevalence and subtypes of Blastocystis sp. in individuals referred to medical laboratories in Ahvaz city, southwest Iran.

Methods: From September 2014 to September 2015, 618 stool samples were collected from 16 medical laboratories in Ahvaz, and examined using direct wet mount, formalin-ether concentration, a modified version of the Ziehl–Neelsen staining technique, and cultivation in xenic HSr + S medium. Subtypes of positive Blastocysts sp. were obtained using the “barcoding” method. The results were analyzed using SPSS software, version 16, with Chi-square and Fisher’s exact test.

Results: Totally, 325 (52.6%) of the referred individuals were men and 293 (47.4%) were women. Blastocystis sp. was observed in 146 (23.6%) samples. Co-infections with other intestinal parasites were found in 32 (5.17%) cases. Out of the 146 positive isolates, 20.83%, 20.83% and 58.34% belonged to ST1, ST2, ST3 respectively.

Conclusion: Blastocystis sp. was quite common in the study population, with a carrier rate corresponding to nearly one in every four individuals. The subtype distribution identified in the present study was largely identical to that reported from other studies in Iran, with ST3 being the most common.

Keywords: Blastocystis, Prevalence, Subtypes. South western Iran.


Blastocystis, Prevalence, Subtypes. Southwestern Iran


Alfellani MA, Stensvold CR, Vidal-Lapiedra A, Uche Onuoha ES, Fagbenro-Beyioku AF, Clark CG. Variable geographic distribution of Blastocystis subtypes and its potential implications. Acta Tropica. 2013;126(1):11– 18.

Popruk S, Pintong. AR, Radomyos P. Diversity of Blastocystis Subtypes in Humans. J Trop Med Parasitol. 2013;36(2):88-97.

Abdulsalam.AM, Ithoi. I, Al-Mekhlafi,HM, Ahmed.A, Johar Surin.J. Subtype Distribution of Blastocystis Isolates in Sebha, Libya. PLoS ONE.2013;8(12):e84372

El Safadi D, Meloni D, Poirier P, Osman M, Cian A, Gaayeb L, Wawrzyniak I, Delbac F, El Alaoui H, Delhaes L, Dei-Cas E, Mallat H, Dabboussi F, Hamze M, Viscogliosi E. Molecular Epidemiology of Blastocystis in Lebanon and Correlation between Subtype 1 and Gastrointestinal Symptoms. Am J Trop Med Hyg. 2013;88(6):1203–1206.

Moosavi A, Haghighi A, Mojarad EN, Zayeri F, Alebouyeh M, Khazan H, Kazemi B, Zali MR. Genetic variability of Blastocystis sp. isolated from symptomatic and asymptomatic individuals in Iran. Parasitol Res. 2012;111(6):2311–2315.

Badparva. E, Fallahi.Sh, Arab-Mazar.Z. Blastocystis: Emerging Protozoan Parasite with High Prevalence in Iran. Novelty in Biomedicine.2015;3(4):214-221

Badparva.E, Sadraee.J, Kheirandish.F, Frozandeh.M. Genetic Diversity of Human Blastocystis Isolates in Khorramabad, Central Iran. Iran J Parasitol. 2014;9(1):44–49.

Sardarian.K, Hajilooi.M, Maghsood.A , Moghimbeigi.A, Alikhani.M. A Study of The Genetic Variability of Blastocystis hominis Isolates in Hamadan, West of Iran. Jundishapur J Microbiol. 2012;5(4):555-559.

- Khoshnood S, Rafiei A., Saki J, Alizadeh K. Prevalence and genotype characterization of Blastocystis hominis among the baghmalek people in southwestern Iran in 2013-2014. Jundishapur J Microbiol. 2015; 8(10):e23930

- Badparva E, Ezatpour, Mahmoudvand H, Behzadifar M, Behzadifar M, Kheirandish K. Prevalence and Genotype Analysis of Blastocystis hominis in Iran: Systematic Review and Meta-Analysis. Arch Clin Infect Dis. 2016;e36648.

- Azizian M, Basati G, Abangah G, Mahmoudi MR, Mirzaei A. Contribution of Blastocystis hominis subtypes and associated inflammatory factors in development of irritable bowel syndrome. Parasitology Research. 2016;115(5):2003-2009

- Motazedian H. Ghasemi H., Sadjjadi SM. Genomic diversity of Blastocystis hominis from patients in southern Iran. Ann Trop Med. Parasitol. 2008;102(1):85-8

Stephanie M. Scicluna, Blessing Tawari, and C. Graham Clark. DNA Barcoding of Blastocystis. Protist. 2006;157(1):77-85.

Dobell. C, Laidlaw P. P. On the cultivation of Entamoeba histolytica and some other entozoic amoebae. Parasitology. 1926;18(3):283-318.

Stensvold CR, Alfellani M, Clark. CG. Levels of genetic diversity vary dramatically between Blastocystis subtypes. Infection, Genetics and Evolution. 2012;12(2):263-273.

Arisue N, Hashimoto T, Yoshikawa H, Nakamura Y, Nakamura G, Nakamura F, et al. Phylogenetic Position of Blastocystis hominis and of Stramenopiles Inferred from Multiple Molecular Sequence Data. Journal of Eukaryotic Microbiology. 2002; 49(1):42-53

Clark CG, van der Giezen M, Alfellani MA, Stensvold CR. Recent development in Blastocystis research. Adv Parasitol. 2013;82:1-32.

Santín M, Gómez-Muñoz MT, Solano-Aguilar G, Fayer R. Development of a new PCR protocol to detect and subtype Blastocystis spp. from humans and animals. Parasitol Res. 2011;109(1);205-212.

Andersen LB, Stensvold CR. Blastocystis in Health and Disease: Are We Moving from a Clinical to a Public Health Perspective? Journal of Clinical Microbiology;2016;54(3):524-3

Babcock D, Houston R, Kumaki D, Shlim D. Blastocystis hominis in Kathmandu, Nepal. N Engl J Med. 1985;313(22):1419.

Keystone JS. Blastocystis hominis and traveler’s diarrhea. Clin Infect Dis. 1995; 21(1):102–3.

Tan KS. New insights on classification, identification and clinical relevance of Blastocystis spp . Clin Microb Rev. 2008;21(4):639-665.

Yunus E. B, Hasan Y, Zeynep.T, Abdurrahman. E. Clinical significance and prevalence of Blastocystis hominis in Van, Turkey. Saudi Med J. 2015;36(9):1118-1121

Clark CG. Extensive genetic diversity in Blastocystis hominis. Mol Biochem Parasitol 1997;87(1):79–83.

Udkow MP, Markell EK. Blastocystis hominis: prevalence in asymptomatic versus symptomatic hosts. J Infect Dis 1993;168(1):242–4

Grossman I, Weiss LM, Simon D, Tanowitz HB, Wittner M. Blastocystis hominis in hospital employees. Am J Gastroenterol 1992;87(6):729–32.

Stensvold CR, Nielsen HV, Mølbak K, Smith HV. Pursuing the clinical significance of Blastocystis – diagnostic limitations. Trend in Parasitology. 2009:23-29.

Scanlan PD. Blastocystis: past pitfalls and future perspectives. Trends Parasitol. 2012;28(8):327-34.

Mehlhorn.H, Tan.KSW, Yoshikawa.H. Blastocystis: Pathogen or Passenger. An Evaluation of 101 Years of Research. Springer Heidelberg 2012.

Wang.W, Bielefeldt-Ohmann.H, Traub,RJ, Cuttell.L, Owen.H. Location and Pathogenic Potential of Blastocystis in the Porcine Intestine.Plos one. 2014;9(8):e103962.

DOI: https://doi.org/10.22037/ghfbb.v0i0.1096