Volume 88, Issue 6
  • ISSN: 0002-9637
  • E-ISSN: 1476-1645



is the most common eukaryotic parasite in the intestinal tract of humans. Because of its potential impact in public health, we acquired the first data concerning the prevalence of this parasite and the frequency of the subtypes (STs) in the Lebanese population. In this study, fecal samples from 220 Lebanese symptomatic and asymptomatic patients were collected and a total of 42 patients (19%) were identified as positive for this parasite by direct-light microscopy of smears. Among these, 36 isolates were genotyped using partial small subunit ribosomal RNA gene sequencing. The ST distribution in the present Lebanese population was as follows: ST3 (33.3%), ST2 (33.3%), ST1 (30.6%), and ST4 (2.8%). These data were compared with those available in other Middle Eastern and neighboring countries. Finally, ST1 was significantly more prevalent among symptomatic patients of this Lebanese population.


Article metrics loading...

Loading full text...

Full text loading...



  1. Tan KS, , 2008. New insights on classification, identification, and clinical relevance of Blastocystis spp. Clin Microbiol Rev 21: 639665.[Crossref]
  2. Boorom KF, Smith H, Nimri L, Viscogliosi E, Spanakos G, Parkar U, Li LH, Zhou XN, Ok UZ, Leelayoova S, Jones MS, , 2008. Oh my aching gut: irritable bowel syndrome, Blastocystis, and asymptomatic infection. Parasit Vectors 1: 40.[Crossref]
  3. Katsarou-Katsari A, Vassalos CM, Tzanetou K, Spanakos G, Papadopoulou C, Vakalis N, , 2008. Acute urticaria associated with amoeboid forms of Blastocystis sp. subtype 3. Acta Derm Venereol 88: 8081.[Crossref]
  4. Stensvold CR, Nielsen HV, Molbak K, Smith HV, , 2009. Pursuing the clinical significance of Blastocystis – diagnostic limitations. Trends Parasitol 25: 2329.[Crossref]
  5. Tan KS, Mirza H, Teo JD, Wu B, MacAry PA, , 2010. Current views on the clinical relevance of Blastocystis spp. Curr Infect Dis Rep 12: 2835.[Crossref]
  6. Poirier P, Wawrzyniak I, Vivarès CP, Delbac F, El Alaoui H, , 2012. New insights into Blastocystis spp.: a potential link with irritable bowel syndrome. PLoS Pathog 8: e1002545.[Crossref]
  7. Denoeud F, Roussel M, Noël B, Wawrzyniak I, Da Silva C, Diogon M, Viscogliosi E, Brochier-Armamet C, Couloux A, Poulain J, Segurans B, Anthouard V, Texier C, Blot N, Poirier P, Ng GC, Tan KS, Antiguenave F, Jaillon O, Aury J, Delbac F, Wincker P, Vivarès CP, El Alaoui H, , 2011. Genome sequence of the stramenopile Blastocystis, a human anaerobic parasite. Genome Biol 12: R29.[Crossref]
  8. Stensvold CR, Suresh GK, Tan KS, Thompson RC, Traub RJ, Viscogliosi E, Yoshikawa H, Clark CG, , 2007. Terminology for Blastocystis subtypes-a consensus. Trends Parasitol 23: 9396.[Crossref]
  9. Stensvold CR, Alfellani MA, Nørskov-Lauritsen S, Prip K, Victory EL, Maddox C, Nielsen HV, Clark CG, , 2009. Subtype distribution of Blastocystis isolates from synanthropic and zoo animals and identification of a new subtype. Int J Parasitol 39: 473479.[Crossref]
  10. Parkar U, Traub RJ, Vitali S, Elliot A, Levecke B, Robertson I, Geurden T, Steele J, Drake B, Thompson RC, , 2010. Molecular characterization of Blastocystis isolates from zoo animals and their animal-keepers. Vet Parasitol 169: 817.[Crossref]
  11. Noël C, Dufernez F, Gerbod D, Edgcomb VP, Delgado-Viscogliosi P, Ho LC, Singh M, Wintjens R, Sogin ML, Capron M, Pierce R, Zenner L, Viscogliosi E, , 2005. Molecular phylogenies of Blastocystis isolates from different hosts: implications for genetic diversity, identification of species, and zoonosis. J Clin Microbiol 43: 348355.[Crossref]
  12. Scanlan PD, , 2012. Blastocystis: past pitfalls and future perspectives. Trends Parasitol 28: 327334.[Crossref]
  13. Stensvold CR, Lewis HC, Hammerum AM, Porsbo LJ, Nielsen SS, Olsen KE, Arendrup MC, Nielsen HV, Molbak K, , 2009. Blastocystis: unraveling potential risk factors and clinical significance of a common but neglected parasite. Epidemiol Infect 137: 16551663.[Crossref]
  14. Scicluna SM, Tawari B, Clark CG, , 2006. DNA barcoding of Blastocystis . Protist 157: 7785.[Crossref]
  15. Stensvold CR, Arendrup MC, Jespersgaard C, Molbak K, Nielsen HV, , 2007. Detecting Blastocystis using parasitologic and DNA-based methods: a comparative study. Diagn Microbiol Infect Dis 59: 303307.[Crossref]
  16. Souppart L, Sanciu G, Cian A, Wawrzyniak I, Delbac F, Capron M, Dei-Cas E, Boorom K, Delhaes L, Viscogliosi E, , 2009. Molecular epidemiology of human Blastocystis isolates in France. Parasitol Res 105: 413421.[Crossref]
  17. Poirier P, Wawrzyniak I, Albert A, El Alaoui H, Delbac F, Livrelli V, , 2011. Development and evaluation of a real-time PCR assay for detection and quantification of Blastocystis parasites in human stool samples: prospective study of patients with hematological malignancies. J Clin Microbiol 49: 975983.[Crossref]
  18. Rayan HL, Ismail OA, El Gayar EK, , 2007. Prevalence and clinical features of Dientamoeba fragilis infections in patients suspected to have intestinal parasite infection. J Egypt Soc Parasitol 37: 599608.
  19. Moosavi A, Haghighi A, Nazemalhosseini Mojarad E, Zayeri F, Alebouyeh M, Khazan H, Kazemi B, Zali MR, , 2012. Genetic variability of Blastocystis sp. isolated from symptomatic and asymptomatic individuals in Iran. Parasitol Res 111: 23112315.[Crossref]
  20. Meloni D, Poirier P, Mantini C, Noël C, Gantois N, Wawrzyniak I, Delbac F, Chabé M, Delhaes L, Dei-Cas E, Fiori PL, El Alaoui H, Viscogliosi E, , 2012. Mixed human intra- and inter-subtype infections with the parasite Blastocystis sp. Parasitol Int 61: 719722.[Crossref]
  21. Dogruman-Al F, Yoshikawa H, Kustimur S, Balaban N, , 2009. PCR-based subtyping of Blastocystis isolates from symptomatic and asymptomatic individuals in a major hospital in Ankara. Parasitol Res 106: 263268.[Crossref]
  22. Eroglu F, Koltas IS, , 2010. Evaluation of the transmission mode of B. hominis by using PCR method. Parasitol Res 107: 841845.[Crossref]
  23. Souppart L, Moussa H, Cian A, Sanciu G, Poirier P, El Alaoui H, Delbac F, Boorom K, Delhaes L, Dei-Cas E, Viscogliosi E, , 2010. Subtype analysis of Blastocystis isolates from symptomatic patients in Egypt. Parasitol Res 106: 505511.[Crossref]
  24. Fouad SA, Basyoni MM, Fahmy RA, Kobaisi MH, , 2011. The pathogenic role of different Blastocystis hominis genotypes isolated from patients with irritable bowel syndrome. Arab J Gastroenterol 12: 194200.[Crossref]
  25. Forsell J, Granlund M, Stensvold CR, Clark GC, Evengard B, , 2012. Subtype analysis of Blastocystis isolates in Swedish patients. Eur J Clin Microbiol Infect Dis 31: 16891696.[Crossref]
  26. Stensvold CR, Christiansen DB, Olsen KE, Nielsen HV, , 2011. Blastocystis sp. subtype 4 is common in Danish Blastocystis-positive patients presenting with acute diarrhea. Am J Trop Med Hyg 84: 883885.[Crossref]
  27. Yan Y, Su S, Lai R, Liao H, Ye J, Li X, Luo X, Chen G, , 2006. Genetic variability of Blastocystis isolates in China. Parasitol Res 99: 597601.[Crossref]
  28. Eroglu F, Genc A, Elgun G, Koltas IS, , 2009. Identification of Blastocystis hominis isolates from asymptomatic and symptomatic patients by PCR. Parasitol Res 105: 15891592.[Crossref]
  29. Yakoob J, Jafri W, Beg MA, Abbas Z, Naz S, Islam M, Khan R, , 2010. Irritable bowel syndrome: is it associated with genotypes of Blastocystis hominis . Parasitol Res 106: 10331038.[Crossref]
  30. Hussein EM, Hussein AM, Eida MM, Atwa MM, , 2008. Pathophysiological variability of different genotypes of human Blastocystis hominis egyptian isolates in experimentally infected rats. Parasitol Res 102: 853860.[Crossref]
  31. Özyurt M, Kurt Ö, Molbak K, Nielsen HV, Haznedaroglu T, Stensvold CR, , 2008. Molecular epidemiology of Blastocystis infections in Turkey. Parasitol Int 57: 300306.[Crossref]
  32. Jantermtor S, Pinlaor P, Sawadpanich K, Pinlaor S, Sangka A, Wilailuckana C, Wongsena W, Yoshikawa H, , 2012. Subtype identification of Blastocystis spp. isolated from patients in a major hospital in northeastern Thailand. Parasitol Res. 2012 Dec 9 [Epub ahead of print]. doi:10.1007/s00436-012-3218-x.

Data & Media loading...

  • Received : 22 Dec 2012
  • Accepted : 09 Jan 2013

Most Cited This Month

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error