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: http://dx.doi.org/10.1093/femsec/fiv072

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 (www.blastomeeting2015.com)!

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" (http://www.sgm.ac.uk/) is going to fund two nights of accommodation for 40 young researchers (below 40 years old) attending the 1st International Blastocystis Symposium (www.blastomeeting2015.com).

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]yahoo.com)

Looking forward to seeing you in Ankara...

Unstained Blastocystis. Courtesy of Dr Marianne Lebbad.

Thursday, April 30, 2015

This Month in Blastocystis Research (APR 2015)

#ECCMID2015 took place in Copenhagen. It was a great venue with a lot of interesting sessions. My favourite presentation was by Dr Paul D Cotter. We have had the pleasure of doing some work together with Dr Pauline D Scanlan as the main driving force. In his talk, Dr Cotter highlighted the emergence of research exploring whether certain organisms are pathobionts or probionts; among these, Blastocystis. Among many things, Dr Cotter reviewed the two recent Blastocystis-specific publications by Scanlan et al. focusing on the commonness and stability of Blastocystis colonisation [1] and on the need to use subtype-specific PCRs to detect and identify mixed subtype colonisation/infection [2].

Based at TEAGASC - Ireland, the Cotter/Scanlan group is one of the teams interested in looking into the ecology of Blastocystis (and other microbial eukaryotes of the gut), including its influence of the parasite on gut microbiota/microbiome (structure and function of our all gut organisms) and vice versa, and I'm sure that there will be a lot of interesting data coming out from their lab in the near future.

Cotter mentioned that Blastocystis has been subject to bad science. This may be due to a number of reasons. When developing hypotheses, we have a tendency of opting for dichotomous outcomes - either it is this or that, - maybe that's the very nature of hypotheses. If the clinical significance of Blastocystis is dependent on a number of different things such as co-colonising microbes (cross-talk), differences in host immunity response, Blastocystis subtype, and host diet for instance, then the true tapestry of physiological/biological/clinical mechanisms is likely to be extremely difficult to uncover. Moreover, despite the fact that so many people are curious about the public health significance of Blastocystis, apparently very little funding for targeted Blastocystis research exists. This means that mostly minor and not so significant studies ("cheap studies") on Blastocystis are available. Relatively little seminal research has been done in the clinical field (including the field of gastroenterology), and most studies on Blastocystis are cross-sectional and descriptive and usually not very well designed/carried out (use of diagnostic tools with limited sensitivity, for instance).

Maybe things will change when more and more people realise that we might be able to use Blastocystis as a biomarker/surrogate marker of intestinal homeostasis...

In my opinion the following topics would make for good research projects:

1) Large studies of both diseased cohorts and healthy individuals, including Blastocystis subtype data and data on accompanying protists, bacteria and fungi (16S/18S/ITS profiling).
2) Manipulaton studies where Blastocytsis (cysts) are introduced in ecosystems (in vitro or in vivo) to monitor potential changes.
3) Animal models using cyst challenge (to look at microbiota profile changing upon challenge, and, if in vivo colitis models are used, impact on host immunity)
4) Longitudinal microbiome studies of patients with and without Blastocystis.
5) Investigation of Blastocystis as a biomarker/surrogate marker of microbiota profiles and gut microbiome homeostasis... similar to my recent blog post: 'Show me your gut bacteria, and I'll tell you if you have Blastocystis!'
6) Comparative genomics (virulence gene identification for instance).
7) Identification of Blastocystis-specific signatures in metagenomics data sets.
8) Identification of drugs that have anti-Blastocystis properties, since currently, there is no drug regimen that consistently enables eradication of Blastocystis.

Speaking of which: We just published data in Journal of Ethnopharmacology on the anti-Blastocystis activity of 24 plant parts from 21 medicinal plants from Ghana [3]. We performed in vitro challenge of 48 h Blastocystis cultured cells (subtype 4) using ethanolic, warm and cold water plant extracts. Screening of these 24 different plant parts showed significant anti-Blastocystis activity of six of the ethanolic extracts: Mallotus oppositifolius, IC50, 24h 27.8 µg/mL; Vemonia colorata, IC50, 24h 117.9 µg/mL; Zanthoxylum zanthoxyloides, cortex IC50, 24h 255.6 µg/mL; Clausena anisata, IC50, 24h 314.0 µg/mL; Z. zanthoxyloides, radix IC50, 24h 335.7 µg/mL and Eythrina senegalensis, IC50, 24h 527.6 µg/mL. The reference anti-protozoal agent metronidazole (MTZ) had an IC50, 24h of 7.6 µg/mL. Since cultures were xenic, antimicrobial activity was tested against two Gram-positive and two Gram-negative bacteria for all 24 plant parts at a final concentration of 1 mg/mL. Only C. anisata showed antimicrobial activity at a concentration of 800 µg/mL.

Hence, M. oppositifolius showed nearly as good activity as the reference anti-protozoal drug MTZ. Historically, the active plants found in this study have been used against dysentery, diarrhoea or other stomach disorders. Nowadays they are not used specifically for dysentery, but they are being used as medicinal plants against various stomach disorders.

Our book 'Biology of Foodborne Parasites' is out and available for ordering.

Incidentally, Blastocystis earned a designated chapter in the book 'Biology of Foodborne Parasites' which is now out and available for ordering here. It was fun writing it up, and hope that the chapter will be of interest to health care professionals and students around the world. The book also contains  introductions to the public health importance of foodborne parasites, molecular biological techniques in studies of foodborne parasites, and detection of parasites in foods.


[1] 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   

[2] Scanlan PD, Stensvold CR, & Cotter PD (2015). Development and application of Blastocystis subtype-specific PCR reveals that mixed subtype infections are common in a healthy human population. Applied and Environmental Microbiology PMID: 25841010

[3] Bremer Christensen C, Soelberg J, Stensvold CR, & Jäger AK (2015). Activity of medicinal plants from Ghana against the parasitic gut protist Blastocystis. Journal of Ethnopharmacology PMID: 25773490

Tuesday, March 31, 2015

This Month in Blastocystis Research - MAR 2015

"Show me your gut bacteria and I'll tell you if you're infected with Entamoeba"

One of my 'partners in crime', science reporter Jop de Vrieze, made me aware of a study just published now by Elise R Morton and colleagues. The study appeared in bioRxiv—The Preprint Server for Biology, operated by Cold Spring Harbor Laboratory. The study is totally in line with one of the research foci in our lab.

The paper is called 'Variation in rural African gut microbiomes is strongly shaped by parasitism and diet', and can be downloaded here. The backbone in this type of research is the recognition that studies revealing a large contrast between the microbiomes of populations in developing countries and those of populations in urban industrialised areas have shown that geography is an important factor associated with the gut microbiome, but that such studies yet have to disentangle the effects of factors such as climate, diet, host genetics, hygiene and parasitism.

It's very refreshing that for once, 'parasitism' is included in such considerations. As mentioned in one or more of my previous blog posts, we have metagenomics data stongly indicating that Blastocystis colonisation is associated with certain microbial communities. As of yet, we have no idea about cause and effet, but the idea alone is immensely intriguing.

A large and a small cyst of Entamoeba coli. Courtesy of Dr Marianne Lebbad.
Now, Morton et al. have produced data that suggest that the presence of Entamoeba—another gut-associated eukaryotic genus comprising multiple species of varying pathogencitiy—is strongly correlated with microbial composition and diversity. They showed that an individual's liability to being infected by Entamoeba could be predicted with 79% accuracy based on gut microbiome composition.

The authors used 16S PCR and Illumina-based sequencing of 16S amplicons, and I could have wished that molecular assays, e.g., the 18S PCR that we have developed in our lab + associated software, had also been used to test the faecal samples from the 64 individuals enrolled in the study in order to obtain more precise data, not only on Entamoeba but also on other human-associated gut protists, such as Blastocystis.

While alpha (intra-host) diversity of Entamoeba-positive individuals was significantly higher than that of Entamoeba-negative individuals, analysis of the beta (inter-host) diversity revealed that gut communities across Entamoeba-positive individuals were more similar than across Entamoeba-negative individuals, suggesting that, as alpha diversity increases, there are fewer potential stable states for individual gut communities, or that infection by Entamoeba drives changes in the microbiome that are dominant over other factors.

Right—this is Entamoeba, I know, but in principle, the type of analyses that were performed in the present study could be applicable to Blastocystis, Dientamoeba, and other gut parasites, which may help us understand their role in health and disease. Are these parasites able to influence gut microbiota? Can they be used for gut microbiota manipulation? Or do they only infect people with certain microbiota profiles? Time will show... maybe.

For those of you who would like to read more about what is shaping our microbiomes and how the gut microbiota may impact on our gastrointestinal health, I recently did a couple of blog posts for United European Gastroenterology (UEG) Education that might be of some interest:

Are we finally saluting the fungal kingdom as a co-ruler of GI health and disease?

The intestinal microbiome—Rosetta Stone or Tower of Babel?


Morton ER, Lynch J, Froment A, Lafosse S, Heyer E, Przeworski M, Blekham R, Segurel L.
Variation in rural African gut microbiomes is strongly shaped by parasitism and diet. bioRxiv doi