Sunday, November 1, 2015

This Month in Blastocystis Research (OCT 2015)

I'm actually going to skip the small review I do each month for a variety of reasons. Instead, I'm just going to upload a presentation I gave in Tilburg, The Netherlands, a bit more than a week ago, before attending the UEG Week in Barcelona.

I uploaded it to Google Drive, hoping that it will be easy to download for everyone interested. I have not included any notes, hoping that the slides will be pretty much self-explanatory.

I think there is even a bit of Danish in there, - hope you don't mind! Also, the preview option does not work very well, so make sure you download it.

If the presentation left you wondering a bit and wish for more, why not look up my publications listed in PubMed? They are available here.  Some of them can be downloaded for free.

Thank you for your attention.

Monday, October 5, 2015

This Month in Blastocystis Research (SEP 2015)

The month of September saw the publication of the first data on Blastocystis subtypes going out from Qatar. Abu-Madi and colleagues--who have already been quite prolific in terms of surveying intestinal parasitic infections in Qatar--studied the positive rate of Blastocystis in 608 apparently healthy subjects arriving in Qatar for the first time, identifying a prevalence of 71% as identified by PCR. Strikingly, the positive rate by microscopy of the corresponding samples was only 7%. Three subtypes were idenfied, with ST3 being the most common subtype, followed in prevalence by ST1 and ST2. The study is important for at least two reasons: It confirms the drawback of basing Blastocystis epidemiological research on data generated using microscopy alone, and it confirms the virtual absence of ST4 outside of Europe.

Increased sensitivity of PCR relative to microscopy was also confirmed in a study carried out in Malaysia (I presume) by Ragavan and colleagues. This group surveyed the Blastocystis positivity rate among IBS and non-IBS patients analyzing colonic aspirates, including a total of 109 individuals. Given the data available on Blastocystis prevalence, I was quite surprised to learn that this group failed to detect Blastocystis in any of the samples by microscopy and culture. Using PCR (the subtype-specific [STS] primers were used as diagnostic primers), the group identified Blastocystis in 6 IBS patients and 4 non-IBS patients. Also these figures appear quite low. However, there is very little information available on the non-IBS patients, and since all study individuals were subject to colonscopy, this group of individuals might be suffering chronic and potentially severe intestinal disease, including for instance colorectal cancer, inflammatory bowel disease, etc., which would explain the low prevalence of Blastocystis observed among these individuals. Indeed, evidence is accumulating that the more "gut healthy" you are, the larger the probability of being Blastocystis-positive. I noticed that the colonic aspirates were spun down using 3,000 rpm prior to culture and microscopy; this process might have had an impact on cell viability and morphology; still, DNA should be detectable following this process. Meanwhile, we recently showed (Scanlan et al., 2015) that the sensitivity of the STS primers is relatively low, which is why the use of real-time PCR is recommendable for PCR-based screening. To see an example of how the STS primers perform relative to barcoding primers, go here (Suppl Table 2).
Moreover, care should be taken when reading this paper, since I'm fairly convinced that the subtype terminology used in the study is different from the consensus terminology (Stensvold et al., 2007). It says that the subtypes detected included ST2, ST3, ST4, and ST5; if this reflects the terminology that went along with the original description of the STS primers, these subtypes correspond to ST7, ST3, ST6, and ST2, which to me would be a more likely subtype distribution, taking this particular region into consideration, and given the fact that ST5 appears to be extremely rare in humans. 

It's always interesting to expand on the natural host spectrum of Blastocystis. The parasite has been found in a perplexing array of hosts, but some host specificity has been observed. When it comes to animals held by humans as livestock or pets, we know that pigs and cattle are commonly, if not consistently, colonised by Blastocystis with some quite specific subtypes. With regard to pets, dogs and cats have been found positive, but there seems to be increasing evidence that these animals are not natural hosts (see also Wang et al., 2013). Osman and colleagues, recently published a survey on Cryptosporidium and Blastocystis in dogs using sensitive molecular methods, demonstrating a prevalence of Blastocystis of only about 3%. Moreover, the subtypes 2 and 10 were found, and ST10 is found mostly in cattle, and never before in dogs, as far as I know, which could suggest accidental colonisation - and possibly not a very long-lasting one. Similarly, when humans are found to be colonised with subtypes rarely found in humans, such as ST6, ST7, and ST8, it would be interesting to know for how long these subtypes are capable of "staying put" in the human intestine.


Abu-Madi M, Aly M, Behnke JM, Clark CG, & Balkhy H (2015). The distribution of Blastocystis subtypes in isolates from Qatar. Parasites & Vectors, 8 PMID: 26384209

Osman M, Bories J, El Safadi D, Poirel MT, Gantois N, Benamrouz-Vanneste S, Delhaes L, Hugonnard M, Certad G, Zenner L, & Viscogliosi E (2015). Prevalence and genetic diversity of the intestinal parasites Blastocystis sp. and Cryptosporidium spp. in household dogs in France and evaluation of zoonotic transmission risk. Veterinary Parasitology PMID: 26395822   

Ragavan, N., Kumar, S., Chye, T., Mahadeva, S., & Shiaw-Hooi, H. (2015). Blastocystis sp. in Irritable Bowel Syndrome (IBS) - Detection in Stool Aspirates during Colonoscopy PLOS ONE, 10 (9) DOI: 10.1371/journal.pone.0121173  

Scanlan PD, Stensvold CR, & Cotter PD (2015). Development and Application of a Blastocystis Subtype-Specific PCR Assay Reveals that Mixed-Subtype Infections Are Common in a Healthy Human Population. Applied and Environmental Microbiology, 81 (12), 4071-6 PMID: 25841010   

Stensvold CR, Suresh GK, Tan KS, Thompson RC, Traub RJ, Viscogliosi E, Yoshikawa H, & Clark CG (2007). Terminology for Blastocystis subtypes--a consensus. Trends in Parasitology, 23 (3), 93-6 PMID: 17241816

Wang W, Cuttell L, Bielefeldt-Ohmann H, Inpankaew T, Owen H, & Traub RJ (2013). Diversity of Blastocystis subtypes in dogs in different geographical settings. Parasites & vectors, 6 PMID: 23883734

Tuesday, September 1, 2015

This Month in Blastocystis Research (AUG 2015)

I would like to highlight a comment that we published in PLoS Pathogens, - a paper that is free for download here. It gained some attention on Twitter, and it was recently reviewed in the Faculty of 1000.

We basically highlight the tricky situation that we so often encounter in the field of clinical microbiology, namely the one in which all non-fungal organisms isolated from the human intestinal tract are being referred to collectively as 'parasites'. The word 'parasite' has a negative connotation, indicating that the organism exploits the host with detrimental effects on the host. While this is true for some ciliates, for instance Giardia, other ciliates may in fact be mutualists, which means that these organisms have adapted to a life within a host, providing the host with one or more advantages. One such example is seen in herbivores, where ciliates and flagallates break down cellulose.

In the clinical microbiology lab we face different types of organisms when dealing with stool samples: Giardia, Cryptosporidium and Entamoeba histolytica are considered true parasites, i.e. organisms benefitting from the environment of a host, at the expense of the host, and symptoms such as diarrhoea may develop, indicating host damage. Parasites such as Cryptospordium are usually infecting an individual for a short while, with immunity developing. Meanwhile, we also encounter eukaryotic organisms that are known to be able to colonise the intestine for a very long time, - decades, without being expelled by the host; Blastocystis belong to this group. For some reason it is as if the body 'tolerates' the presence of the organism. Maybe Blastocystis is good at evading local immune responses, or maybe the body wishes to 'keep' Blastocystis for some reason and so  developed a way to tolerate it... as I've hinted at before on this blog, maybe Blastocystis may assist us in one or more metabolic processes, for instance, either directly or indirectly, maybe by selecting for or influencing bacterial communities. Indeed, we recently found evidence of Blastocystis being specifically related to certain groups of bacteria, which, if confirmed, opens up for a whole new line of research, including the use of Blastocystis as a probiotic.

I know that this last sentence may sound harsh in some people's ears; nevertheless, most research involving Blastocystis so far has been quite static and unimaginative, and it's about time that food microbiologist and the like start taking an interest in the micro-eukaryotes that tend to be common and stable conolisers of our guts.

If YOU take an interest in this topic, I suggest you look up the articles cited below.

References and further reading:

Andersen LO, Bonde I, Nielsen HB, & Stensvold CR (2015). A retrospective metagenomics approach to studying Blastocystis. FEMS Microbiology Ecology, 91 (7) PMID: 26130823

Lukeš J, Stensvold CR, Jirků-Pomajbíková K, & Wegener Parfrey L (2015). Are Human Intestinal Eukaryotes Beneficial or Commensals? PLoS Pathogens, 11 (8) PMID: 26270819

Parfrey LW, Walters WA, & Knight R (2011). Microbial eukaryotes in the human microbiome: ecology, evolution, and future directions. Frontiers in Microbiology, 2 PMID: 21808637

Scanlan PD, Stensvold CR, Rajilić-Stojanović M, Heilig HG, De Vos WM, O'Toole PW, & Cotter PD (2014). The microbial eukaryote Blastocystis is a prevalent and diverse member of the healthy human gut microbiota. FEMS Microbiology Ecology, 90 (1), 326-30 PMID: 25077936

Friday, July 31, 2015

This Month in Blastocystis Research (JUL 2015)

This is the holiday version of the 'This Month...' series, and so I thought I'd give you a break from my usual rantings on Blastocystis and instead provide you with some ideas and links to interesting people and resources that could entertain you on your holiday. And where to look if not to social media?

On Twitter, I have come across a few interesting profiles:

Rosemary Drisdelle with the twitter handle @ParasitesAuthor tweets on Blastocystis and many other parasites. She has also has a website, which can be accessed here,  she hosts a blog, and she has written a book that you can read about here.

A colleague of mine, whom I've probably mentioned before, is Dr Bobbi Pritt, who is also on Twitter (@ParasiteGal) and hosts an amazing blog called Creepy, Dreadful, Wonderful Parasites. Here, she weekly posts cases of parasite infections, presented as quizzes. If you're into this, I also recommend visiting a similar site hosted by the CDC.

A recent and appartently popular tweet featuring Dr Pritt was posted by Mayo Clinic (@MayoClinic) yesterday:

If you're interested in the evolution of protists and eukaryotic taxonomy and even enjoy having a bit of vibrant personality added to that, I highly recommend following @Ocelloid, who until recently hosted a blog on Scientific American.

I would also like to recommend following @MicrobiomDigest, @Phylogenomics, @Jopdevrieze @hollybik, just to mention a few if you like to stay updated on research, discussions and hypotheses on gut microbiome structure and function, which is a topic that these guys tweet about every now and then.

If you take an interest in parasitology in general, make sure never to miss out on This Week in Parasitism. I also recommend that you take a look at my Useful Links & Blogrolls, which you'll find in the right side bar (you'd probably need to scroll down a bit). It's been a while since I checked the links, and maybe one or two will not be valid, apologies in advance for that. However, there should be quite a few interesting things there...

A facebook group on Parasites & Parasitology with more than 27,000 members is available here, and there is also a FB community on Blastocystis with more than 1,700 members here.

As I've mentioned before, Brendan Faegre has actually composed a three-movement piece for orchestra on Blastocystis, which can be accessed here. He writes:

The first movement captures the calamity and chaos of millions of one-celled organisms successfully breaching security and going on a joy-ride through my gut, multiplying at a blinding pace and damaging at least 20 feet of my intestines. The second movement reflects the parasitic nature of B. Hominis musically through a continual spreading of the opening motive to new voices; a steady, strength-in-numbers type of proliferation that is eventually joined by the raucous character from the first movement. The final movement is named after the anti-protazoal agent most commonly prescribed to eliminate the B. Hominis from its host, and represents an epic battle of microscopic proportions between Nitazoxanide and the pathogenic, unwelcome guests. Every time this piece is performed, the musical spirits within me are further empowered to fight off the blastocysts and eliminate them for good.

I myself have two Twitter handles, including @Eukaryotes and @Blastocystis, and I post blog posts, conference information, job offers, paper reviews, etc. on Blastocystis, other parasites and gastroenterology to my Facebook page, which is available here.

All of you looking forward to a bit of vacation in August: Enjoy!

Wednesday, July 1, 2015

This Month in Blastocystis Research (JUN 2015)

I started developing this blog more than three years ago. After a bit more than a year, I collected a bunch of the posts, edited them and published them as a book on Amazon. Recently, I logged into my Amazon profile to see how the book was doing, and I was very pleased to notice that there were no less than four reviews of the book, and very positive ones too! Thank you to everyone who read/browsed it.

Blastocystis research is currently a quickly moving field, and I'm please to be able to inform you that one of the most interesting contributions to Blastocystis research coming out from our intstitute has just been published in Fems Microbiology Ecology. The article appearing in this journal was first-authored by PhD student Lee O'Brien Andersen (Statens Serum Institut) and post doc Ida Bonde (Danish Technical University) and describes how Lee and Ida took a retrospective approach to analysing metagenomics data originally generated by the MetaHIT Consortium and published in the often cited paper by Arumugam et al. (2012).

The abstract reads as follows:
Blastocystis is a common single-celled intestinal parasitic genus, comprising several subtypes. Here, we screened data obtained by metagenomic analysis of faecal DNA for Blastocystis by searching for subtype-specific genes in co-abundance gene groups, which are groups of genes that co-vary across a selection of 316 human faecal samples, hence representing genes originating from a single subtype. The 316 faecal samples were from 236 healthy individuals, 13 patients with Crohn's disease (CD), and 67 patients with ulcerative colitis (UC). The prevalence of Blastocystis was 20.3% in the healthy individuals and 14.9% in patients with UC. Meanwhile, Blastocystis was absent in patients with CD. Individuals with intestinal microbiota dominated by Bacteroides were much less prone to having Blastocystis-positive stool (Matthew's correlation coefficient = -0.25, P < 0.0001) than individuals with Ruminococcus- and Prevotella-driven enterotypes. This is the first study to investigate the relationship between Blastocystis and communities of gut bacteria using a metagenomics approach. The study serves as an example of how it is possible to retrospectively investigate microbial eukaryotic communities in the gut using metagenomic datasets targeting the bacterial component of the intestinal microbiome and the interplay between these microbial communities.

As far as we know this is the first study to sift out data on Blastocystis from data originally intended for analysis of bacterial communities only, and in the paper we describe how this was done. We believe that this approach has imminent potential for quickly advancing our knowledge on Blastocystis in a gut ecology context, including knowledge on the role of Blastocystis in terms of impacting/manipulating one or more types of intestinal bacteria.

I have a feeling that this is the first study in a string of similar studies that will soon hit PubMed, and within a year or two, we should be able to with confidence to hypothesise on the relationship between the structure and function on of the gut microbiota and Blastocystis, and–hopefully–other intestinal micro-eukaryotes.

Lastly, it was very interesting to note the article by Paramsothy et al. on donor recruitment for faecal microbiota transplantation (FMT; never heard of this? Watch the video below to learn more), recently appearing in the journal Inflammatory Bowel Disease. The study is interesting because it shows that most FMT donors are seemingly ineligible due to a variety of reasons, including colonisation by intestinal parasites such as Blastocystis... Given emerging data suggesting that Blastocystis is more common in healthy invididuals than in patients with gastrointestinal disease, the question remains whether Blastocystis-positivity should be a limiting factor for stool donation?


Andersen LO, Bonde I, Nielsen HB, Stensvold CR. A retrospective metagenomics approach to studying Blastocystis. Published online 30 June 2015. DOI:

Paramsothy S, Borody TJ, Lin E, Finlayson S, Walsh AJ, Samuel D, van den Bogaerde J, Leong RW, Connor S, Ng W, Mitchell HM, Kaakoush N, & Kamm MA (2015). Donor Recruitment for Fecal Microbiota Transplantation. Inflammatory bowel diseases, 21 (7), 1600-6 PMID: 26070003

Monday, June 8, 2015

Memories from 1st International Blastocystis Symposium

I'm going to release a tsunami of photos from the 1st International Blastocystis Symposium, hoping that they will help everyone involved commemorate this fantastic event but also in order to share a few moments with the rest of the 'Blastocystis community'.

Dr Funda Dogruman-Al giving her opening remarks.

In his opening lecture, Dr Graham Clark summarised the advances in Blastocystis research over the past century.

Coffee break outside the plenary room.

Graham and me with Iranian delegates, including Dr Elham Razmjou.

Drs Shashiraja Padukone and Chen-Chieh Liao trying out the local ney flutes...

Dr Hisao Yoshikawa enjoying a bit of masterclass...

Funda with her wonderful students and staff who helped making it all happen.

During coffee breaks, we had time to enjoy a variety of art exhibitions.

Dr Kevin Tan busy with his camera as usual!

Mesmerising "Turkish Delight"...

Funda and me busy handing out awards...

Chen-Chieh Liao receives the prize for the third-best poster, the book 'Blastocystis - pathogen or passenger', from Dr Hisao Yoshikawa, one of the editors.

Erdogan Malatyali won the prize for the best oral presentation.

I was very honoured to receive a plate from Prof Dr Sacit Turanli.

Some of the delegates, members of the arrangement committee, staff and students.

Funda and me with Dr Özgür Kurt and Funda's fantastic students.

The Clark couple with Funda, Özgür, and Funda's students.

Drs Kevin Tan, Javed Jakoob, Philippe Poirier, Hisao Yoshikawa together with Funda and her students.

A great couple in Turkish microbiology: Drs Özgür Kurt and Funda Dogruman-Al.

The six prize winners (please see previous blog post for names and affiliations).

Funda Dogruman-Al teaching Blastocystis diagnostic methods at the pre-Symposium workshop...

The workshop included both practicals...

... and theoreticals.

Some of the workshop participants.

Turkish food is probably palatable to most ethnicities...

The mandatory Turkish coffee did not let us down!

We were absolutely spoiled with good food and drink along the way... I clearly remember how it was pouring down outside!

Sunday, May 31, 2015

This Month in Blastocystis Research (MAY 2015)

Words cannot describe my gratitude for being part of the 1st International Blastocystis Symposium, which was seen through to marvelous success by Dr Funda Dogruman-Al, her colleagues and students, her professional arrangement committee and the scientific committee, made up by Dr Graham Clark, Dr Kevin Tan, Dr Hisao Yoshikawa, Professor Ibrahim Dogan, Funda Dogruman-Al, and myself.

Funda Dogruman-Al in the middle flanked by some of the delegates outside Gazi Hastanesi.

A total of 70 delegates had registered, comprising 37 national and 33 international attendees. Countries represented included Australia, Japan, Russia, China, Taiwan, India, Pakistan, Qatar, Iran, Iraq, Turkey, Spain, France, Denmark, UK, USA, and Mexico.

Some of the delegates gathering before the gala dinner.

A presymposium workshop taking place the day before the launching of the actual symposium focussed on methods for diagnosis and molecular epidemiological studies of Blastocystis.

The two-day symposium included 13 half-hour lectures, 10 shorter oral presentations, and 27 posters.

Lectures were given by Dr Graham Clark (one of his three talks was on behalf on Prof Andrew Roger and post doc Laura Eme), Dr Kevin Tan, Dr Hisao Yoshikawa, Dr Philippe Poirier, Dr Özgür Kurt, Dr Javed Jakoob, Dr Funda Dogruman-Al, and myself, and covered updates on genomics, cell biology, host-parasite interactions, genetic diversity, epidemiology, clinical significance, treatment, and methods used for detection and molecular characterisation.

We were spoilt with lots of 'Turkish Delight': Here are some of the dancers performing at the gala dinner.

There were six prizes in total; three for the best oral presentations and three for the best posters. Prize money was donated by Elsevier.

The prize winners were as follows: 

Oral presentations:
1st Prize: Erdogan Malatyali, Adnan Menderes University, Aydin, Turkey
2nd Prize: Sitara SR Ajjampur, National University of Singapore, Singapore
3rd Prize: Unaiza Parkar, Murdoch University, Murdoch, Western Australia

Poster presentations:
1st Prize:  John Anthony Yason, National University of Singapore, Singapore
2nd Prize: Joel Martinez-Ocana, Universidad Nacional Autonoma de Mexico, Ciudad Universitaria, Mexico City, Mexico
3rd Prize: Chen-Chieh Liao, National Cheng Kung University, Taiwan

Over the next few months, original manuscripts – seminal papers and reviews – will be developed for a special issue on Blastocystis in of Parasitology International to mark the event.

An important landmark in Blastocystis history has been made, and we are already looking into our chances of developing the 2nd International Blastocystis Symposium, which may be in 2017.

A huge THANK YOU to Funda for all her efforts, and KUDOS to all contributors for making this such a fantastic event!

Friday, May 1, 2015

Expected Social/Cultural Activities at 1st International Blastocystis Symposium

A lot of thrilling activities and ideas are in the making for the 1st International Blastocystis Symposium in Ankara later this month (!

For instance, the social programme is expected to include the following:

1) Performances of Turkish classical music and folk music by students from Gazi University State Conservatory of Turkish Music at the opening and closing ceremonies
2) Needle work exhibition
3) Traditional Turkish arts exhibition
4) Glass work workshop
5) Marbling workshop
6) Gilding workshop 
7) Reed flute (‘ney’) contest

This should provide the delegates with lots of opportunity to meet different branches of Turkish culture.

Hence, the ceremonies + coffee breaks and lunches will be busy and fun! For the Gala Dinner we are currently trying to engage with two different folk dancer teams from Gazi University… and...(suspense!)...  there might be a chance the Gala Dinner will be free of charge for all participants! Stay tuned!

1st International Blastocystis Symposium - Accommodation Funding!

We are pleased to announce that "Society for General Microbiology" ( is going to fund two nights of accommodation for 40 young researchers (below 40 years old) attending the 1st International Blastocystis Symposium (

Those who apply with a presentation and with no other funding will have priority in application.

Please inform your other colleagues who are interested in Blastocystis research about this important news.

(Please note: Applications should be sent to alfunda[at]

Looking forward to seeing you in Ankara...

Unstained Blastocystis. Courtesy of Dr Marianne Lebbad.