Saturday, March 31, 2012

Blastocystis Treatment

In my opinion, in many cases we should "leave Blastocystis alone". In some cases, however, treatment may be warranted. However, currently there are no convincing drug regimens. RCTs needed.
For more information, please consult this review. 

European Congress on Tropical Medicine and International Health in CPH 2013

Don't forget the VIII’th ECTMIH in Copenhagen September 10-13, 2013, - click here to get flyer.

Why not speculate on our possibilities to host a symposium/work shop on Blastocystis? Potential topics:

1) Blastocystis in the "omics" era - possibilities and perspectives
2) Recent advances in Blastocystis research
3) Standardisation in Blastocystis epidemiological research methodologies

We have been colonised!

Time to revisit: Why it is a bugs life by Jörg Blech (The Guardian (2002)). Speaking of numbers, - I wonder which one is the most successful eukaryote in terms of numbers? Blasto?

Some updates on Blastocystis

Blastocystis is a micro-eukaryote, a so-called protist, parasitising the intestine of humans and a variety of animals.

We estimate that at least 1 billion people worldwide are colonised by this parasite, and we believe that the majority experience no more episodes of intestinal upset, e.g. diarrhoea, than the average individual.

Blastocystis colonises the intestine for a long time (probably months or years).

Many species of Blastocystis are known, of which at least 9 have been found in humans. Such species are currently termed "subtypes" (STs). ST1, ST2, ST3 and ST4 are common in Europe. While ST1, ST2, and ST3 appear to have equal prevalences in patients with diarrhoea and healthy individuals, ST4 appears to be linked to diarrhoea and/or chronic conditions such as irritable bowel syndrome (IBS).

There is no known efficient treatment of Blastocystis. Although metronidazole is often prescribed for Blastocystis infections, there is conflicting reports on its efficacy. Even in combination with a luminal agent, such as paromomycin, Blastocystis eradication cannot be guaranteed.

Whether Blastocystis causes symptoms in humans may depend on factors such as co-evolution. ST3 is the most common subtype in humans and ST3 may account for 30-50% of Blastocystis in humans. ST3 shows substantial intra-subtype genetic variation, and we believe that Blastocystis ST3 has co-evolved with humans, and therefore we may have adapted to ST3 colonisation. ST4 on the other hand is almost clonal and may have entered the human population relatively recently. This could partly explain why ST4 colonisation has been linked to intestinal symptoms.

Further reading:
1. Stensvold CR, Alfellani M, Clark CG. Levels of genetic diversity vary dramatically between Blastocystis subtypes.
2. Stensvold CR, Christiansen DB, Olsen KE, Nielsen HV. Blastocystis sp. ST4 is common in Danish Blastocystis-positive patients presenting with acute diarrhea.

Friday, March 30, 2012

XXVIII SBPz Meeting in Caxambu, Brazil in October - key note on Blastocystis

Looking forward to giving key note talk at XXVIII SBPz (SociedadeBrasileira de Protozoologia) in Caxambu - Minas Gerais - Brazil in October. Title of talk: Blastocystis - friend or foe?

Blastocystis - An Opportunistic Pathogen?

Browsed the paper by Chandramathi et al. (2012) on Infections of Blastocystis hominis and microsporidia in cancer patients: are they opportunistic? I'm surprised about the low prevalence incidence of Blastocystis... I'm also suprised that the authors do not mention potential disturbance of the gut flora by antineoplastic drugs that could influence colonisation of Blastocystis.

Thursday, March 29, 2012

Blastocystis makes it to PLoS Pathogens!

Whether "New Insights" or not: Blastocystis makes it to PLoS Pathogens! Congratulations to our colleagues!

New Insights into Blastocystis spp.: A Potential Link with Irritable Bowel Syndrome

Blastocystis Sequence Type Home Page - use it!

For all of you interested in subtyping of Blastocystis:

We recommend using barcoding (look up the paper by Scicluna et al., 2012 for primer sequences and gene target). Sequences can easily be assigned to subtype and even allele by using the blast alogorithm at

The Blastocystis Sequence Type Home Page

Batch submission of sequences even possible... should enable some speedy results!

Another Risk Factor Study

Absence of a piped water supply and low levels of mothers' education were the significant predictors of Blastocystis infection in a recent study of school children in Lipis and Raub districts of Pahang state, Malaysia (Abdulsalam et al., 2012)

Drinking water is a significant predictor of Blastocystis infection among rural Malaysian primary schoolchildren.

The study shows the clear benefit of using culture as opposed to e.g. concentration of fresh stools, and reports an overall prevalence of 25.7%. Looking forward to subtype data...

Novel Blastocystis real-time PCR

Our new real-time PCR for Blastocystis has been published in JCM.

Check it out at

Development and evaluation of a genus-specific, probe-based, internal process controlled real-time PCR assay for sensitive and specific detection of Blastocystis.


and use it!