About Blastocystis

Blastocystis is a highly prevalent single-celled parasite that infects the gastrointestinal tract of humans and animals.  It has become the most prevalent gastrointestinal parasitic infection in developed and many developing countries, and it will produce long-term diarrhea, abdominal pain, and other symptoms in healthy individuals.

BRF’s web site has written and audio descriptions from patients, information on the newest research in diagnosis and treatment of Blastocystis ’hominis’ infection, and information on BRF”s advocacy program.

Large study (n=10,466) reports statistically higher incidence of low serum iron, high c-reactive protein, and occult blood in Blastocystis-positive patients

A study of 10,466 patients seen at an Iran hospital reports that patients with stool samples positive for Blastocystis infection were statistically more likely to have low serum iron levels.  Additionally, occult blood was positive in 0.93% of Blastocystis-positive cases, and none of the control (p < 0.05).  C-reactive protein was positive in 1.46% of the cases and 0.5% of controls.  Erythrocyte sedimentation rate level was significantly higher in cases with Blastocystis infection as well (p < 0.05).  The full free text is available from Przeglad Gastroenterology.

Researchers from St. Vincent’s Hospital in Australia have published a review and update on the pathogenic potential and treatment options for Blastocystis infection.  The paper describes a number of patient cases, summarizes current information on the life cycle and pathology of Blastocystis infection, and notes that many of the currently used treatments may provide a low degree of success in eradicating the infection.  The full free text is available from Gut Pathogens.

Blastocystis isolates from symptomatic humans behave differently from those from asymptomatic individuals

Researchers from the University of Malaysia report that Blastocystis cultures from symptomatic individuals report different behavior with respect to capase-like proteases.  Fluorescence intensity for active capase-like proteases was significantly greater in isolates from symptomatic individuals in the 72-hour in vitro culture (p < 0.001).  Treatment with metronidazole inhibited the capase activation.  The full free text is available from Parasites and Vectors.

 

Fecal IgA reactivity to >250 kDa Blastocystis protein more common in immunosuppressed pigs, but no intestinal histopathology

An Australian team has used fecal IgA study to characterize the immune response of 233 pigs to Blastocystis antigens.   The team reports that a majority of the pigs (81.5%) show fecal IgA reactivity against Blastocystis proteins of molecular weight 17.5-120kDa, but reactivity to a higher weight protein (>250kDa) was found in only 18.5% of the pigs.  Immunosuppressed pigs and piglets were much more likely to show reactivity to the high molecular weight protein.  The full free text of the paper is available from Parasite Immunology.

Study of 275 Columbian children shows higher prevalence of diarrhea in children infected with Blastocystis

Columbian researchers studying 275 children attending under 5 attending day care centers in Calarca, Columbia report that children infected with Blastocystis had a significantly higher prevalence of diarrhea (OR=1.95, 95% CI, p < 0.05), with 45% of Blastocystis-positive children reporting diarrhea vs. 33% of Blastocystis-negative children.  Etiological study suggested that Blastocystis infection may come from contamination of a sugar cane beverage, floors, or foods other than bottled milk.  The full free text is available from Biomedica.

Multiplex DNA panel identifies many gastrointestinal pathogen not found in microscopy from pediatric patients returning from the tropics

Researchers in Switzerland studying 312 stool samples from pediatric patients returning from trips to the tropics report that conventional laboratory methods failed to identify most of the norovirus-positive and Giardia-positive samples identified by Luminex’s xTag gastrointestinal pathogen panel.  The Luminex panel covers 15 diarrhea-causing organisms using PCR amplification.  All adenovirus, rotavirus, C. diff, and Cryptosporidium samples were confirmed in external labs, but norovirus and Giarida positive samples were only idneitifes 40% and 29% of the time respectively.  For more information, refer to the paper published in the journal Infection.

Blastocystis found in both small intestine and large intestine of pigs

A report from a research team at the from the University of Queensland, Australia has identified Blastocystis infection in both the small and large intestines of pigs.  By studying a total of 28 pigs infected with Blastocystis, the authors found that the primary types observed were Blastocystis sp. subtypes 3 and 1.  The researchers suggested that pigs may provide suitable animals models for Blastocystis infection in humans.  The full text of the study is available from PLOS-One.

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Researchers in Malaysia report high prevalence of parasitic infections in rural populations, lower prevalence in urban

A research team from Universiti Kuala Lumpur Royal College of Medicine has reviewed findings of 101 studies conducted over 42 years (1970-2013).  The team reports high levels of parasitism in rural populations, but a significant decline in urban populations over the time period.  The full text of the study is available in Tropical Biomedicine.

Blastocystis activates variety of pro-inflammatory cytokines in variety of mice cells

A research team from the National University of Singapore reports that Blastocystis antigens stimulate the production of a variety of cytokines, such as 1β (IL-1β), IL-6, and tumor necrosis factor alpha (TNF-α), in mouse intestinal explants, in mouse colitis colon, and in macrophages.  Further investigation utilizing RAW264.7 murine macrophages showed that Blastocystis treatment in RAW264.7 macrophages induced the activation of ERK, JNK, and p38, the three major groups of mammalian mitogen-activated protein (MAP) kinases that play essential roles in the expression of proinflammatory cytokines. ERK inhibition in macrophages significantly suppressed both mRNA and protein expression of IL-6 and TNF-α and mRNA expression of IL-1β.  For the full text of the study, refer to the journal Infection and Immunity