Me and My Research

Brief introduction:

I'm a senior scientist based at Statens Serum Institut, Copenhagen, Denmark at the Department of Microbiology and Infection Control.

Together with excellent colleagues, I have in few years contributed significantly to what today is known about Blastocystis, an intestinal parasite of unknown clinical significance colonising/infecting hundreds of millions of people in both developed and developing countries. I have published about 55 seminal and review articles in peer-reviewed, international journals focussing entirely or partly on Blastocystis.

During my PhD I took the initiative to standardise Blastocystis terminology and evaluate diagnostic methods; I managed to cross correlate and interpret a vast pool of molecular data from different research labs. Thanks to these efforts, researchers across the globe now employ the same terminology for Blastocystis, and a clear picture of the relative distribution of different subtypes in various cohorts in various countries is now building up.

I have detected and delineated several new species (ribosomal lineages) of protistan genera such as Entamoeba, Iodamoeba and Blastocystis, and I was the first ever to report on Dientamoeba fragilis in Denmark.

Output from my research has provided incentive for improving routine diagnosis of intestinal parasites and has resulted in the implementation of novel, DNA-based methods for the routine screening of patients with diarrhoea for intestinal parasites of clinical relevance. My research has had a major impact on current guidelines for the detection of intestinal parasites and offers a critical approach to the implementation of novel technology in different fields of clinical microbiology.

I have been able to attract substantial funding by myself and in collaboration with colleagues.

Ongoing research in our lab also includes a randomised controlled treatment study of Dientamoeba fragilis infections in children in Denmark.

I have supervised dozens of Bachelor and MSc students, and co-supervised PhD students.

- Bachelor of Medicine (University of Aarhus, Denmark)
- MSc in Parasitology (University of Copenhagen, Denmark)
- PhD in Health Sciences (University of Copenhagen, Denmark)

- Field work: WHO, Vientiane, Lao PDR (2003)
- PhD training at Murdoch University, Western Australia (2006)
- Post doc studies at London School of Hygiene & Tropical Medicine, London, UK (2009-2012)

Key research interests:
- Parasitology
- Mycology
- Clinical Microbiology
- Infectious Diseases
- Gastroenterology

More than 130 papers in national and international peer-reviewed journals
First paper appeared in 2006
H-index: 40
M-index: 2.7

Grants obtained by myself:
2013: Brdr. Hartmanns Fond (Denmark), €12,000
2012: Lundbeck Foundation (Denmark), €200,000
2012: Marie Curie Career Reintegration Grant (EU), €100,000
2012: Danish Agency for Science Technology and Innovation, €15,000
2012: TRYG Fonden (Denmark), €46,000
2011: AP Møller Foundation (Denmark), €6,000
2009: Danish Agency for Science Technology and Innovation, €230,000

2013: Fritz Kauffmann Prize (Denmark), €10,000.

Extra-curricular activities:
- A history of several board memberships
- Associate Faculty Member of Faculty 1000.
- Reviewer for > 30 scientific journals, including CMR, JCM, IJP, Trends in Parasitology, Eurosurveillance.

Social media:
I've got an updated CV here.
Follow me on Twitter.
There is Facebook group on Blastocystis as well and the Blastocystis Parasite Blog also appears on Facebook.

ORCID # 0000-0002-1417-7048

Scientific Articles:
  • Paulos S, Köster PC, de Lucio A, Hernández-de-Mingo M, Cardona GA, et al. Occurrence and subtype distribution of Blastocystis sp in humans, dogs and cats sharing household in northern Spain and assessment of zoonotic transmission risk. Zoonoses Public Health. 2018 Dec;65(8):993-1002. PubMed PMID: 30198123.
  • Stensvold CR, Tilma J, Tilma J, Tilma K. [Fasciola hepatica infection acquired in Denmark]. Ugeskr Laeger. 2018 Oct 29;180(44)PubMed PMID: 30375969.
  • Růžková J, Květoňová D, Jirků M, Lhotská Z, Stensvold CR, et al. Evaluating rodent experimental models for studies of Blastocystis ST1. Exp Parasitol. 2018 Aug;191:55-61. PubMed PMID: 29959915.
  • Vaisusuk K, Saijuntha W, Sedlak S, Thanchomnang T, Pilap W, et al. Blastocystis subtypes detected in long-tailed macaques in Thailand-Further evidence of cryptic host specificity. Acta Trop. 2018 Aug;184:78-82. PubMed PMID: 28887122.
  • Krogsgaard LR, Andersen LO', Johannesen TB, Engsbro AL, Stensvold CR, et al. Characteristics of the bacterial microbiome in association with common intestinal parasites in irritable bowel syndrome. Clin Transl Gastroenterol. 2018 Jun 19;9(6):161. PubMed PMID: 29915224; PubMed Central PMCID: PMC6006308.
  • Stensvold CR, van der Giezen M. Associations between Gut Microbiota and Common Luminal Intestinal Parasites. Trends Parasitol. 2018 May;34(5):369-377. PubMed PMID: 29567298.
  • Stensvold CR, Winiecka-Krusnell J, Lier T, Lebbad M. Evaluation of a PCR Method for Detection of Entamoeba polecki, with an Overview of Its Molecular Epidemiology. J Clin Microbiol. 2018 May;56(5)PubMed PMID: 29491022; PubMed Central PMCID: PMC5925701.
  • Röser D, Bjerrum S, Helleberg M, Nielsen HV, David KP, et al. Adventure tourism and schistosomiasis: serology and clinical findings in a group of Danish students after white-water rafting in Uganda. JMM Case Rep. 2018 Apr;5(4):e005141. PubMed PMID: 29868173; PubMed Central PMCID: PMC5982149.
  • Mirjalali H, Abbasi MR, Naderi N, Hasani Z, Mirsamadi ES, et al. Distribution and phylogenetic analysis of Blastocystis sp subtypes isolated from IBD patients and healthy individuals in Iran. Eur J Clin Microbiol Infect Dis. 2017 Dec;36(12):2335-2342. PubMed PMID: 28741097.
  • Carrillo-Ávila JA, Serrano-García ML, Fernández-Parra J, Sorlózano-Puerto A, Navarro-Marí JM, et al. Prevalence and genetic diversity of Trichomonas vaginalis in the general population of Granada and co-infections with Gardnerella vaginalis and Candida species. J Med Microbiol. 2017 Oct;66(10):1436-1442. PubMed PMID: 28972465.
  • Williams AR, Dige A, Rasmussen TK, Hvas CL, Dahlerup JF, et al. Immune responses and parasitological observations induced during probiotic treatment with medicinal Trichuris suis ova in a healthy volunteer. Immunol Lett. 2017 Aug;188:32-37. PubMed PMID: 28602842.
  • Laranjo-González M, Devleesschauwer B, Trevisan C, Allepuz A, Sotiraki S, et al. Epidemiology of taeniosis/cysticercosis in Europe, a systematic review: Western Europe. Parasit Vectors. 2017 Jul 21;10(1):349. PubMed PMID: 28732550; PubMed Central PMCID: PMC5521153.
  • Salehi R, Haghighi A, Stensvold CR, Kheirandish F, Azargashb E, et al. Prevalence and subtype identification of <i>Blastocystis</i> isolated from humans in Ahvaz, Southwestern Iran. Gastroenterol Hepatol Bed Bench. 2017 Summer;10(3):235-241. PubMed PMID: 29118941; PubMed Central PMCID: PMC5660275.
  • Jokelainen P, Hebbelstrup Jensen B, Andreassen BU, Petersen AM, Röser D, et al. Dientamoeba fragilis, a Commensal in Children in Danish Day Care Centers. J Clin Microbiol. 2017 Jun;55(6):1707-1713. PubMed PMID: 28330885; PubMed Central PMCID: PMC5442526.
  • Alinaghizade A, Mirjalali H, Mohebali M, Stensvold CR, Rezaeian M. Inter- and intra-subtype variation of Blastocystis subtypes isolated from diarrheic and non-diarrheic patients in Iran. Infect Genet Evol. 2017 Jun;50:77-82. PubMed PMID: 28238960.
  • Nissen J, Jokelainen P, Stensvold CR, Trevisan C, Fuchs J, et al. The disease burden of congenital toxoplasmosis in Denmark, 2014. PLoS One. 2017;12(5):e0178282. PubMed PMID: 28558051; PubMed Central PMCID: PMC5448755.
  • Jacob AS, Andersen LO, Bitar PP, Richards VP, Shah S, et al. Blastocystis Mitochondrial Genomes Appear to Show Multiple Independent Gains and Losses of Start and Stop Codons. Genome Biol Evol. 2016 Dec 14;8(11):3340-3350. PubMed PMID: 27811175; PubMed Central PMCID: PMC5203790.
  • Dogruman-Al F, Stensvold CR, Yoshikawa H. Editorial - PAR INT - special issue on Blastocystis. Parasitol Int. 2016 Dec;65(6 Pt B):749. PubMed PMID: 27742000.
  • Stensvold CR, Clark CG. Current status of Blastocystis: A personal view. Parasitol Int. 2016 Dec;65(6 Pt B):763-771. PubMed PMID: 27247124.
  • Clark CG, Stensvold CR. Blastocystis: Isolation, Xenic Cultivation, and Cryopreservation. Curr Protoc Microbiol. 2016 Nov 18;43:20A.1.1-20A.1.8. PubMed PMID: 27858970.
  • Stensvold CR, Clark CG. Molecular Identification and Subtype Analysis of Blastocystis. Curr Protoc Microbiol. 2016 Nov 18;43:20A.2.1-20A.2.10. PubMed PMID: 27858971.
  • Cacciò SM, Sannella AR, Bruno A, Stensvold CR, David EB, et al. Multilocus sequence typing of Dientamoeba fragilis identified a major clone with widespread geographical distribution. Int J Parasitol. 2016 Nov;46(12):793-798. PubMed PMID: 27555056.
  • Dakić Z, Nielsen HV, Pavlović M, Poluga J, Stevanović G, et al. Retrospective PCR-based species identification of <i>Leishmania</i> in two patients with visceral leishmaniasis in Serbia. JMM Case Rep. 2016 Oct;3(5):e005063. PubMed PMID: 28348785; PubMed Central PMCID: PMC5343143.
  • O'Brien Andersen L, Karim AB, Roager HM, Vigsnæs LK, Krogfelt KA, et al. Associations between common intestinal parasites and bacteria in humans as revealed by qPCR. Eur J Clin Microbiol Infect Dis. 2016 Sep;35(9):1427-31. PubMed PMID: 27230509.
  • Hebbelstrup Jensen B, Stensvold CR, Struve C, Olsen KE, Scheutz F, et al. Enteroaggregative Escherichia coli in Daycare-A 1-Year Dynamic Cohort Study. Front Cell Infect Microbiol. 2016;6:75. PubMed PMID: 27468409; PubMed Central PMCID: PMC4942469.
  • Poulsen CS, Efunshile AM, Nelson JA, Stensvold CR. Epidemiological Aspects of Blastocystis Colonization in Children in Ilero, Nigeria. Am J Trop Med Hyg. 2016 Jul 6;95(1):175-9. PubMed PMID: 27139454; PubMed Central PMCID: PMC4944538.
  • Stubhaug TT, Reiakvam OM, Stensvold CR, Hermansen NO, Holberg-Petersen M, et al. Fatal primary amoebic meningoencephalitis in a Norwegian tourist returning from Thailand. JMM Case Rep. 2016 Jun;3(3):e005042. PubMed PMID: 28348761; PubMed Central PMCID: PMC5330229.
  • Andersen LO, Stensvold CR. Blastocystis in Health and Disease: Are We Moving from a Clinical to a Public Health Perspective?. J Clin Microbiol. 2016 Mar;54(3):524-8. PubMed PMID: 26677249; PubMed Central PMCID: PMC4767957.
  • Putignani L, Del Chierico F, Vernocchi P, Cicala M, Cucchiara S, et al. Gut Microbiota Dysbiosis as Risk and Premorbid Factors of IBD and IBS Along the Childhood-Adulthood Transition. Inflamm Bowel Dis. 2016 Feb;22(2):487-504. PubMed PMID: 26588090.
  • Bangsø J, Thøgersen KF, Nejsum P, Stensvold CR. [The first case of Hypoderma tarandi-associated human myiasis in Greenland]. Ugeskr Laeger. 2016 Jan 4;178(1):V10150796. PubMed PMID: 26750192.
  • Poulsen CS, Stensvold CR. Systematic review on Endolimax nana: A less well studied intestinal ameba. Trop Parasitol. 2016 Jan-Jun;6(1):8-29. PubMed PMID: 26998431; PubMed Central PMCID: PMC4778187.
  • AbuOdeh R, Ezzedine S, Samie A, Stensvold CR, ElBakri A. Prevalence and subtype distribution of Blastocystis in healthy individuals in Sharjah, United Arab Emirates. Infect Genet Evol. 2016 Jan;37:158-62. PubMed PMID: 26611823.
  • Bremer Christensen C, Soelberg J, Stensvold CR, Jäger AK. Activity of medicinal plants from Ghana against the parasitic gut protist Blastocystis. J Ethnopharmacol. 2015 Nov 4;174:569-75. PubMed PMID: 25773490.
  • Hawash MB, Andersen LO, Gasser RB, Stensvold CR, Nejsum P. Mitochondrial Genome Analyses Suggest Multiple Trichuris Species in Humans, Baboons, and Pigs from Different Geographical Regions. PLoS Negl Trop Dis. 2015;9(9):e0004059. PubMed PMID: 26367282; PubMed Central PMCID: PMC4569395.
  • Lukeš J, Stensvold CR, Jirků-Pomajbíková K, Wegener Parfrey L. Are Human Intestinal Eukaryotes Beneficial or Commensals?. PLoS Pathog. 2015 Aug;11(8):e1005039. PubMed PMID: 26270819; PubMed Central PMCID: PMC4536199.
  • Efunshile MA, Ngwu BA, Kurtzhals JA, Sahar S, König B, et al. Molecular Detection of the Carriage Rate of Four Intestinal Protozoa with Real-Time Polymerase Chain Reaction: Possible Overdiagnosis of Entamoeba histolytica in Nigeria. Am J Trop Med Hyg. 2015 Aug;93(2):257-62. PubMed PMID: 26101274; PubMed Central PMCID: PMC4530744.
  • Andersen LO, Bonde I, Nielsen HB, Stensvold CR. A retrospective metagenomics approach to studying Blastocystis. FEMS Microbiol Ecol. 2015 Jul;91(7)PubMed PMID: 26130823.
  • Scanlan PD, Stensvold CR, Cotter PD. Development and Application of a Blastocystis Subtype-Specific PCR Assay Reveals that Mixed-Subtype Infections Are Common in a Healthy Human Population. Appl Environ Microbiol. 2015 Jun 15;81(12):4071-6. PubMed PMID: 25841010; PubMed Central PMCID: PMC4524157.
  • Stensvold CR, Elwin K, Winiecka-Krusnell J, Chalmers RM, Xiao L, et al. Development and Application of a gp60-Based Typing Assay for Cryptosporidium viatorum. J Clin Microbiol. 2015 Jun;53(6):1891-7. PubMed PMID: 25832304; PubMed Central PMCID: PMC4432048.
  • Röser D, Simonsen J, Nielsen HV, Stensvold CR, Mølbak K. History of antimicrobial use and the risk of Dientamoeba fragilis infection. Eur J Clin Microbiol Infect Dis. 2015 Jun;34(6):1145-51. PubMed PMID: 25663130.
  • Stensvold CR, Al Marai D, Andersen LO, Krogfelt KA, Jensen JS, et al. Babesia spp and other pathogens in ticks recovered from domestic dogs in Denmark. Parasit Vectors. 2015 May 8;8:262. PubMed PMID: 25951937; PubMed Central PMCID: PMC4425907.
  • Stensvold CR, Ethelberg S, Hansen L, Sahar S, Voldstedlund M, et al. Cryptosporidium infections in Denmark, 2010-2014. Dan Med J. 2015 May;62(5)PubMed PMID: 26050832.
  • Pandey PK, Verma P, Marathe N, Shetty S, Bavdekar A, et al. Prevalence and subtype analysis of Blastocystis in healthy Indian individuals. Infect Genet Evol. 2015 Apr;31:296-9. PubMed PMID: 25701123.
  • Efunshile AM, Olawale T, Stensvold CR, Kurtzhals JA, König B. Epidemiological study of the association between malaria and helminth infections in Nigeria. Am J Trop Med Hyg. 2015 Mar;92(3):578-82. PubMed PMID: 25624401; PubMed Central PMCID: PMC4350553.
  • Krogsgaard LR, Engsbro AL, Stensvold CR, Nielsen HV, Bytzer P. The prevalence of intestinal parasites is not greater among individuals with irritable bowel syndrome: a population-based case-control study. Clin Gastroenterol Hepatol. 2015 Mar;13(3):507-513.e2. PubMed PMID: 25229421.
  • Halkjær S, Stensvold CR, Petersen AM. [Dientamoeba fragilis infection as cause of severe abdominal discomfort and flatulence]. Ugeskr Laeger. 2015 Jan 26;177(2A):30-1. PubMed PMID: 25612954.
  • Stensvold CR. Laboratory diagnosis of Blastocystis spp. Trop Parasitol. 2015 Jan-Jun;5(1):3-5. PubMed PMID: 25709945; PubMed Central PMCID: PMC4326991.
  • Scanlan PD, Stensvold CR, Rajilić-Stojanović M, Heilig HG, De Vos WM, et al. The microbial eukaryote Blastocystis is a prevalent and diverse member of the healthy human gut microbiota. FEMS Microbiol Ecol. 2014 Oct;90(1):326-30. PubMed PMID: 25077936.
  • Poulsen CS, Stensvold CR. Current status of epidemiology and diagnosis of human sarcocystosis. J Clin Microbiol. 2014 Oct;52(10):3524-30. PubMed PMID: 24759707; PubMed Central PMCID: PMC4187749.
  • Stensvold CR, Beser J, Ljungström B, Troell K, Lebbad M. Low host-specific Enterocytozoon bieneusi genotype BEB6 is common in Swedish lambs. Vet Parasitol. 2014 Sep 15;205(1-2):371-4. PubMed PMID: 24986434.
  • Stensvold CR, Beser J, Axén C, Lebbad M. High applicability of a novel method for gp60-based subtyping of Cryptosporidium meleagridis. J Clin Microbiol. 2014 Jul;52(7):2311-9. PubMed PMID: 24740082; PubMed Central PMCID: PMC4097674.
  • Röser D, Simonsen J, Stensvold CR, Olsen KE, Bytzer P, et al. Metronidazole therapy for treating dientamoebiasis in children is not associated with better clinical outcomes: a randomized, double-blinded and placebo-controlled clinical trial. Clin Infect Dis. 2014 Jun;58(12):1692-9. PubMed PMID: 24647023.
  • Verweij JJ, Stensvold CR. Molecular testing for clinical diagnosis and epidemiological investigations of intestinal parasitic infections. Clin Microbiol Rev. 2014 Apr;27(2):371-418. PubMed PMID: 24696439; PubMed Central PMCID: PMC3993103.
  • Clark CG, Röser D, Stensvold CR. Transmission of Dientamoeba fragilis: pinworm or cysts?. Trends Parasitol. 2014 Mar;30(3):136-40. PubMed PMID: 24492020.
  • Monroy-Vaca EX, de Armas Y, Illnait-Zaragozí MT, Diaz R, Toraño G, et al. Genetic diversity of Pneumocystis jirovecii in colonized Cuban infants and toddlers. Infect Genet Evol. 2014 Mar;22:60-6. PubMed PMID: 24412726.
  • Engsbro AL, Stensvold CR, Vedel Nielsen H, Bytzer P. Prevalence, incidence, and risk factors of intestinal parasites in Danish primary care patients with irritable bowel syndrome. Scand J Infect Dis. 2014 Mar;46(3):204-9. PubMed PMID: 24344761.
  • Ramírez JD, Sánchez LV, Bautista DC, Corredor AF, Flórez AC, et al. Blastocystis subtypes detected in humans and animals from Colombia. Infect Genet Evol. 2014 Mar;22:223-8. PubMed PMID: 23886615.
  • Monroy-Vaca EX, de Armas Y, Illnait-Zaragozí MT, Toraño G, Diaz R, et al. Prevalence and genotype distribution of Pneumocystis jirovecii in Cuban infants and toddlers with whooping cough. J Clin Microbiol. 2014 Jan;52(1):45-51. PubMed PMID: 24131683; PubMed Central PMCID: PMC3911444.
  • Scanlan PD, Stensvold CR. Blastocystis: getting to grips with our guileful guest. Trends Parasitol. 2013 Nov;29(11):523-9. PubMed PMID: 24080063.
  • Röser D, Stensvold CR. Anisakiasis mistaken for dientamoebiasis?. Clin Infect Dis. 2013 Nov;57(10):1500. PubMed PMID: 23965282.
  • Röser D, Simonsen J, Nielsen HV, Stensvold CR, Mølbak K. Dientamoeba fragilis in Denmark: epidemiological experience derived from four years of routine real-time PCR. Eur J Clin Microbiol Infect Dis. 2013 Oct;32(10):1303-10. PubMed PMID: 23609513.
  • Stensvold CR, Clark CG, Röser D. Limited intra-genetic diversity in Dientamoeba fragilis housekeeping genes. Infect Genet Evol. 2013 Aug;18:284-6. PubMed PMID: 23681023.
  • Alfellani MA, Taner-Mulla D, Jacob AS, Imeede CA, Yoshikawa H, et al. Genetic diversity of blastocystis in livestock and zoo animals. Protist. 2013 Jul;164(4):497-509. PubMed PMID: 23770574.
  • Alfellani MA, Jacob AS, Perea NO, Krecek RC, Taner-Mulla D, et al. Diversity and distribution of Blastocystis sp subtypes in non-human primates. Parasitology. 2013 Jul;140(8):966-71. PubMed PMID: 23561720.
  • Zhao Y, Stensvold CR, Perlin DS, Arendrup MC. Azole resistance in Aspergillus fumigatus from bronchoalveolar lavage fluid samples of patients with chronic diseases. J Antimicrob Chemother. 2013 Jul;68(7):1497-504. PubMed PMID: 23463213; PubMed Central PMCID: PMC3935014.
  • Andersen LO, Vedel Nielsen H, Stensvold CR. Waiting for the human intestinal Eukaryotome. ISME J. 2013 Jul;7(7):1253-5. PubMed PMID: 23407309; PubMed Central PMCID: PMC3695289.
  • Mikaeili F, Kia EB, Sharbatkhori M, Sharifdini M, Jalalizand N, et al. Comparison of six simple methods for extracting ribosomal and mitochondrial DNA from Toxocara and Toxascaris nematodes. Exp Parasitol. 2013 Jun;134(2):155-9. PubMed PMID: 23499880.
  • Petersen AM, Stensvold CR, Mirsepasi H, Engberg J, Friis-Møller A, et al. Active ulcerative colitis associated with low prevalence of Blastocystis and Dientamoeba fragilis infection. Scand J Gastroenterol. 2013 May;48(5):638-9. PubMed PMID: 23528075.
  • Andersen LO, Röser D, Nejsum P, Nielsen HV, Stensvold CR. Is supplementary bead beating for DNA extraction from nematode eggs by use of the NucliSENS easyMag protocol necessary?. J Clin Microbiol. 2013 Apr;51(4):1345-7. PubMed PMID: 23325821; PubMed Central PMCID: PMC3666819.
  • Alfellani MA, Stensvold CR, Vidal-Lapiedra A, Onuoha ES, Fagbenro-Beyioku AF, et al. Variable geographic distribution of Blastocystis subtypes and its potential implications. Acta Trop. 2013 Apr;126(1):11-8. PubMed PMID: 23290980.
  • Stensvold CR. Blastocystis: Genetic diversity and molecular methods for diagnosis and epidemiology. Trop Parasitol. 2013 Jan;3(1):26-34. PubMed PMID: 23961438; PubMed Central PMCID: PMC3745667.
  • Clark CG, van der Giezen M, Alfellani MA, Stensvold CR. Recent developments in Blastocystis research. Adv Parasitol. 2013;82:1-32. PubMed PMID: 23548084.
  • Röser D, Nejsum P, Carlsgart AJ, Nielsen HV, Stensvold CR. DNA of Dientamoeba fragilis detected within surface-sterilized eggs of Enterobius vermicularis. Exp Parasitol. 2013 Jan;133(1):57-61. PubMed PMID: 23116599.
  • Stensvold CR. Comparison of sequencing (barcode region) and sequence-tagged-site PCR for Blastocystis subtyping. J Clin Microbiol. 2013 Jan;51(1):190-4. PubMed PMID: 23115257; PubMed Central PMCID: PMC3536234.
  • Engsbro AL, Stensvold CR, Nielsen HV, Bytzer P. Treatment of Dientamoeba fragilis in patients with irritable bowel syndrome. Am J Trop Med Hyg. 2012 Dec;87(6):1046-52. PubMed PMID: 23091195; PubMed Central PMCID: PMC3516073.
  • Nourmoradi H, Nikaeen M, Stensvold CR, Mirhendi H. Ultraviolet irradiation: An effective inactivation method of Aspergillus spp in water for the control of waterborne nosocomial aspergillosis. Water Res. 2012 Nov 15;46(18):5935-40. PubMed PMID: 22985523.
  • Engsbro AL, Stensvold CR. Blastocystis: to treat or not to treatbut how?. Clin Infect Dis. 2012 Nov 15;55(10):1431-2. PubMed PMID: 22893582.
  • Nagel R, Cuttell L, Stensvold CR, Mills PC, Bielefeldt-Ohmann H, et al. Blastocystis subtypes in symptomatic and asymptomatic family members and pets and response to therapy. Intern Med J. 2012 Nov;42(11):1187-95. PubMed PMID: 22032439.
  • Stensvold CR. Thinking Blastocystis out of the box. Trends Parasitol. 2012 Aug;28(8):305. PubMed PMID: 22704911.
  • Forsell J, Granlund M, Stensvold CR, Clark CG, Evengård B. Subtype analysis of Blastocystis isolates in Swedish patients. Eur J Clin Microbiol Infect Dis. 2012 Jul;31(7):1689-96. PubMed PMID: 22350386.
  • Stensvold CR, Ahmed UN, Andersen LO, Nielsen HV. Development and evaluation of a genus-specific, probe-based, internal-process-controlled real-time PCR assay for sensitive and specific detection of Blastocystis spp. J Clin Microbiol. 2012 Jun;50(6):1847-51. PubMed PMID: 22422846; PubMed Central PMCID: PMC3372105.
  • Stensvold CR, Alfellani M, Clark CG. Levels of genetic diversity vary dramatically between Blastocystis subtypes. Infect Genet Evol. 2012 Mar;12(2):263-73. PubMed PMID: 22116021.
  • Stensvold CR, Nielsen HV. Comparison of microscopy and PCR for detection of intestinal parasites in Danish patients supports an incentive for molecular screening platforms. J Clin Microbiol. 2012 Feb;50(2):540-1. PubMed PMID: 22090410; PubMed Central PMCID: PMC3264173.
  • Stensvold C, Jørgensen LN, Arendrup MC. Azole-Resistant Invasive Aspergillosis: Relationship to Agriculture. Current Fungal Infection Reports. 2012; 6(3):178-191.
  • Stensvold CR, Lebbad M, Clark CG. Last of the human protists: the phylogeny and genetic diversity of Iodamoeba. Mol Biol Evol. 2012 Jan;29(1):39-42. PubMed PMID: 21940643.
  • Malheiros AF, Stensvold CR, Clark CG, Braga GB, Shaw JJ. Short report: Molecular characterization of Blastocystis obtained from members of the indigenous Tapirapé ethnic group from the Brazilian Amazon region, Brazil. Am J Trop Med Hyg. 2011 Dec;85(6):1050-3. PubMed PMID: 22144442; PubMed Central PMCID: PMC3225150.
  • Stensvold CR, Lebbad M, Victory EL, Verweij JJ, Tannich E, et al. Increased sampling reveals novel lineages of Entamoeba: consequences of genetic diversity and host specificity for taxonomy and molecular detection. Protist. 2011 Jul;162(3):525-41. PubMed PMID: 21295520.
  • Stensvold CR, Christiansen DB, Olsen KE, Nielsen HV. Blastocystis sp subtype 4 is common in Danish Blastocystis-positive patients presenting with acute diarrhea. Am J Trop Med Hyg. 2011 Jun;84(6):883-5. PubMed PMID: 21633023; PubMed Central PMCID: PMC3110361.
  • Stensvold CR, Lebbad M, Verweij JJ. The impact of genetic diversity in protozoa on molecular diagnostics. Trends Parasitol. 2011 Feb;27(2):53-8. PubMed PMID: 21168365.
  • Stensvold CR, Nielsen SD, Badsberg JH, Engberg J, Friis-Møller N, et al. The prevalence and clinical significance of intestinal parasites in HIV-infected patients in Denmark. Scand J Infect Dis. 2011 Feb;43(2):129-35. PubMed PMID: 20936912.
  • Stensvold CR, Nielsen HV, Petersen E. [Toxocariasis]. Ugeskr Laeger. 2011 Jan 17;173(3):186-9. PubMed PMID: 21241625.
  • Stensvold CR, Lebbad M, Verweij JJ, Jespersgaard C, von Samson-Himmelstjerna G, et al. Identification and delineation of members of the Entamoeba complex by pyrosequencing. Mol Cell Probes. 2010 Dec;24(6):403-6. PubMed PMID: 20691255.
  • Vogelberg C, Stensvold CR, Monecke S, Ditzen A, Stopsack K, et al. Blastocystis sp subtype 2 detection during recurrence of gastrointestinal and urticarial symptoms. Parasitol Int. 2010 Sep;59(3):469-71. PubMed PMID: 20363362.
  • Stensvold CR, Lebbad M, Clark CG. Genetic characterisation of uninucleated cyst-producing Entamoeba spp from ruminants. Int J Parasitol. 2010 Jun;40(7):775-8. PubMed PMID: 20359482.
  • Stensvold CR, Smith HV, Nagel R, Olsen KE, Traub RJ. Eradication of Blastocystis carriage with antimicrobials: reality or delusion?. J Clin Gastroenterol. 2010 Feb;44(2):85-90. PubMed PMID: 19834337.
  • Sprong H, Cacciò SM, van der Giessen JW. Identification of zoonotic genotypes of Giardia duodenalis. PLoS Negl Trop Dis. 2009 Dec 1;3(12):e558. PubMed PMID: 19956662; PubMed Central PMCID: PMC2777335.
  • Stensvold CR, Lewis HC, Hammerum AM, Porsbo LJ, Nielsen SS, et al. Blastocystis: unravelling potential risk factors and clinical significance of a common but neglected parasite. Epidemiol Infect. 2009 Nov;137(11):1655-63. PubMed PMID: 19393117.
  • Stensvold CR, Skov J, Møller LN, Jensen PM, Kapel CM, et al. Seroprevalence of human toxocariasis in Denmark. Clin Vaccine Immunol. 2009 Sep;16(9):1372-3. PubMed PMID: 19641098; PubMed Central PMCID: PMC2745020.
  • Stensvold CR, Arendrup MC, Nielsen HV, Mølbak K. [Blastocystis--an enigmatic parasite]. Ugeskr Laeger. 2009 Aug 17;171(34):2388-90. PubMed PMID: 19732521.
  • Rene BA, Stensvold CR, Badsberg JH, Nielsen HV. Subtype analysis of Blastocystis isolates from Blastocystis cyst excreting patients. Am J Trop Med Hyg. 2009 Apr;80(4):588-92. PubMed PMID: 19346381.
  • Ethelberg S, Lisby M, Vestergaard LS, Enemark HL, Olsen KE, et al. A foodborne outbreak of Cryptosporidium hominis infection. Epidemiol Infect. 2009 Mar;137(3):348-56. PubMed PMID: 19134228.
  • Stensvold CR, Alfellani MA, Nørskov-Lauritsen S, Prip K, Victory EL, et al. Subtype distribution of Blastocystis isolates from synanthropic and zoo animals and identification of a new subtype. Int J Parasitol. 2009 Mar;39(4):473-9. PubMed PMID: 18755193.
  • Stensvold CR, Nielsen HV, Mølbak K, Smith HV. Pursuing the clinical significance of Blastocystis--diagnostic limitations. Trends Parasitol. 2009 Jan;25(1):23-9. PubMed PMID: 19013108.
  • Ozyurt M, Kurt O, Mølbak K, Nielsen HV, Haznedaroglu T, et al. Molecular epidemiology of Blastocystis infections in Turkey. Parasitol Int. 2008 Sep;57(3):300-6. PubMed PMID: 18337161.
  • Stensvold CR, Arendrup MC, Nielsen HV, Bada A, Thorsen S. Symptomatic infection with Blastocystis sp subtype 8 successfully treated with trimethoprim-sulfamethoxazole. Ann Trop Med Parasitol. 2008 Apr;102(3):271-4. PubMed PMID: 18348782.
  • Duenngai K, Sithithaworn P, Rudrappa UK, Iddya K, Laha T, et al. Improvement of PCR for detection of Opisthorchis viverrini DNA in human stool samples. J Clin Microbiol. 2008 Jan;46(1):366-8. PubMed PMID: 18003810; PubMed Central PMCID: PMC2224308.
  • Stensvold CR, Arendrup MC, Jespersgaard C, Mølbak K, Nielsen HV. Detecting Blastocystis using parasitologic and DNA-based methods: a comparative study. Diagn Microbiol Infect Dis. 2007 Nov;59(3):303-7. PubMed PMID: 17913433.
  • Stensvold CR, Nielsen HV, Mølbak K. A case of trichinellosis in Denmark, imported from Poland, June 2007. Euro Surveill. 2007 Aug 9;12(8):E070809.3. PubMed PMID: 17868552.
  • Stensvold CR, Arendrup MC, Mølbak K, Nielsen HV. The prevalence of Dientamoeba fragilis in patients with suspected enteroparasitic disease in a metropolitan area in Denmark. Clin Microbiol Infect. 2007 Aug;13(8):839-42. PubMed PMID: 17610603.
  • Stensvold CR, Traub RJ, von Samson-Himmelstjerna G, Jespersgaard C, Nielsen HV, et al. Blastocystis: subtyping isolates using pyrosequencing technology. Exp Parasitol. 2007 Jun;116(2):111-9. PubMed PMID: 17266951.
  • Vestergaard LS, Olsen KE, Stensvold R, Böttiger BE, Adelhardt M, et al. Outbreak of severe gastroenteritis with multiple aetiologies caused by contaminated drinking water in Denmark, January 2007. Euro Surveill. 2007 Mar 29;12(3):E070329.1. PubMed PMID: 17439795.
  • Stensvold CR, Suresh GK, Tan KS, Thompson RC, Traub RJ, et al. Terminology for Blastocystis subtypes--a consensus. Trends Parasitol. 2007 Mar;23(3):93-6. PubMed PMID: 17241816.
  • Stensvold R, Brillowska-Dabrowska A, Nielsen HV, Arendrup MC. Detection of Blastocystis hominis in unpreserved stool specimens by using polymerase chain reaction. J Parasitol. 2006 Oct;92(5):1081-7. PubMed PMID: 17152954.
  • Stensvold CR, Saijuntha W, Sithithaworn P, Wongratanacheewin S, Strandgaard H, et al. Evaluation of PCR based coprodiagnosis of human opisthorchiasis. Acta Trop. 2006 Jan;97(1):26-30. PubMed PMID: 16253202.

                      Book chapters:

                      In Molecular Microbiology: Diagnostic Principles and Practice 3rd Edition (March 2016)

                      Chapter 38 : Molecular Detection of Gastrointestinal Parasites 

                       By Jaco J. Verweij, Alex Van Belkum, C. Rune Stensvold


                      DOI 10.1128/9781555819071.ch38


                      The continuously expanding universe of Entamoeba
                      Charles Graham Clark & Christen Rune Stensvold
                      Chapter · January 2015
                      DOI: 10.1007/978-4-431-55200-0_2
                      In book: Amebiasis. Biology and pathogenesis of Entamoeba, Chapter: 2, Publisher: Springer, Editors: Tomoyoshi Nozaki, Alok Bhattacharya, pp.9-25

                      Christen Rune Stensvold
                      Chapter · April 2015
                      CRC Press
                      Reference - 520 Pages - 89 B/W Illustrations
                      ISBN 9781466568839 - CAT# K16405
                      In book: Biology of Foodborne Parasites (edited by Lihua Xiao, Una Ryan, Yaoyu Feng)

                      Endolimax nana
                      Casper Sahl Poulsen & Christen Rune Stensvold

                      Christen Rune Stensvold

                      Katerina Jirku-Pomajbikova & Christen Rune Stensvold

                      Christian Paul de la Cruz & Christen Rune Stensvold

                            Page updated 15 AUG 2019


                            1. Dear Stensfold,
                              Your blog on Blastocystis looks very nice and is informative. What article would you recommend, in which it is proven that Blastocystis is directly associated with disease?
                              You mentioned in your blog that typing hasn't been extensively performed on samples from sub-Saharan Africa. If you are interested, I might know a collection of such fecal DNA that might be used for further research.

                            2. Dear Robert,
                              thank you for stopping by!
                              I'm afraid I have no such article to recommend. There are many theories, but one thing is a fact: A large proportion of the human population is colonised by Blastocystis, and most individuals do not suffer intestinal symptoms, at least over a longer period. Blastocystis has not been associated with any outbreak, invasivness has not been successfully demonstrated, and problems with chemotherapeutic treatment makes RCT studies difficult. Having said that, our French colleagues have published genome data, and Blastocystis does appear to encode potential virulence genes.

                              There are so many things, thoughts and theories to discuss, many of these have been touched upon elsewhere on this blog. Also many opportunities...

                              It's always interesting to look into subtype epidemiology. Please let me know if I can be of any assistance!


                            3. Hi, I just got diagnosed with having Blastocystis. I am writing to you because I thought maybe you would be interested in my symptoms.
                              For Christmas and New Year's I was in Cancun, Mexico with my family. We had swam in the ocean and also in a cenote there. I have a feeling inside of me we were all infected in the Cenote. All of us have been experiencing symptoms since returning from Mexico but we all thought it to be from different causes. My situation is worse than everyone else in my family. After going to the emergency room at my local hospitals on two occasions since returning from Mexico and having X-rays, ultrasounds, blood work, CT Scan, CT with contract, angiogram, EKG, and urine tests, the doctors told me I had anxiety. The reason I went to the hospital is because I have extreme shortness of breath. I have never had this before. I never had asthma or any other symptoms. I literally woke up in the middle of the night gasping for air. Shortly after I began vomiting undigested food and acid so they said I had GERD and anxiety... I never had acidity before. I took all of the meds they gave me and nothing was helping. I had this weird feeling inside of me that was like an empty cold feeling and I just knew something wasn't right. I convinced my doctor to do stool tests in which they found the blastocysts. I had begun a metronidazole regimen right after I turned in my stool samples. I was taking it 3x a day for 7 days with no improvement at all. I did notice a slight improvement with Primal Defense probiotics. I take 3 a day but still feel shortness of breath and my gut is constantly making awful noises. My doctor has now prescribed me Nitazoxinide to take for 3 days with a refill for an additional 3 if it doesn't work. I will let you know how it goes, if you would like.

                            4. Thank you, Louise, for taking your time here on the blog, and for your description of your situation. I would like to reiterate that Blastocystis is a very common parasite, also in the Western world, an asymptomatic carriage is common, at least when it comes to the common subtypes. In case you never had stool tests done (for ova and parasites or some similar test) before you went to Mexico, it's impossible to know whether you were carrying Blastocystis with you to Mexico or you only caught it out there. Your account sounds to me almost like the description of a minor outbreak, which of course would be interesting to investigate in further detail. I wonder whether your family members are carrying Blastocystis too?! Feel free to post your experience on your treatment here. There is also the Blastocystis community on Facebook where you can share your story.

                              Having said that I was starting to think of something else when I read your story, namely the possibility of you having been exposed to free living amoeba of some sort... However, I'm not sure about the salinity in the cenotes there in Mexico... maybe such amoebae cannot live there at all...

                            5. I am on day 4 now of the treatment and it's not working. I did happen to find a center in Australia that works with Blastocyst quite frequently. Maybe you would want to speak with them. Their treatments seem promising.

                              About the salinity in the cenotes, from what I gather, it is rather high and the water is not stagnant, it apparently runs through a labyrinth of under ground caves and the cenotes are sink holes from the ground down to the cave systems.

                              Here is the center in Australia:

                              My daughters still have not been tested. They are charging us $450 for the tests and my doctor seems to think they must have what I have because the symptoms are very similar. Both of my daughters are now having shortness of breath, as well. We have extreme fatigue and our quality of life is drastically reduced from what it was prior to the symptoms appearing.

                              I'm going to try to get my doctor to communicate with this center in Australia and get their meds over here in the US to see if they will work. From what I understand from their page, they use enema like meds to eradicate the blastocysts.

                              I also found this page which has a plethora of comments from people all suffering with Blastocysts and many haven't been able to clear them from their systems:


                              I sincerely hope people start taking this more seriously and no just shrugging it off. I am in pain and really suffering. I hope your research will assist in treating this protozoa nightmare.