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.
A study of 674 Moroccan children from rural and urban areas found that overall, 20% were infected with Giardia intestinalis and 64% with Blastocystis. Blastocystis was found at the same prevalence in children from urban and rural schools. Despite the high rate of parasitism, only 8% of rural children and 7% of urban children had diarrhea, and diarrhea in Blastocystis patients occurred in those co-infected with another parasite. Researchers genotyped Giardia isolates from the children, and found that both Assemblage A (AII) and Assemblage B (BIII, BIV) were present, with the majority of isolates belonging to Assemblage BIV (73%). The full free text of the study is available at the web site of the Parasite Journal.
The Internal Transcribed Spacer, a region situated between structural ribosomes, has been useful in tracking genetic differentiation and variation in fungal organisms and yeasts for some time, and now researchers at the University of Mexico (Mexico City) have reported that it can be used for this purpose in Blastocystis as well. Using Blastocystis samples from 47 children who were symptomatic with diarrhea, the researchers analyzed stool samples for other parasites, and also extracted DNA from fecal samples, and then amplified and analyzed Blastocystis sequences. None of the children selected were found to have bacterial pathogens, and none were identified as carrying any pathogenic parasitic infection other than Blastocystis. DNA extracted from fecal samples, subtyped Blastocystis isolates using the standard methodology, and almost all infections were found to be of type ST1, ST2, or ST3, with a roughly even distribution between the three subtypes. Examining existing sequences in Genbank, the researchers found that a high gene flow exists between European and American isolates for ST1 and ST2. ST3 showed extremely high gene flow between Asia and Africa. Also, there was a high gene flow for ST3 between Asia and the Americas, and between Asia and Europe. The full text of the article is available for free at BMC Parasites and Vectors site.
Russian physicians have reported on extra-intestinal Blastocystis infection in a 65-year old female patient suffering from a liver abscess, following surgery for removal of colonic polyps. Pathologists identified Blastocystis cells, along with liver cells and inflammatory cells in aspirates from the patient’s liver. The patient made a full recovery following treatment with broad spectrum antibiotics and an imidazole antiparasitic drug (imidazole drugs are of the miconazole, fluconazole, clotrimazole family) The study authors suggested this case illustrated the importance of investigating Blastocystis infection in immunocompromised patients. Link to NIH Pubmed entry.
Researchers from Oregon State University, publishing in the journal PLOS-One, report that Blastocystis infection is highly prevalent in animals studied at a local animal shelter.
The researchers report that Blastocystis was found in 10/103 (9.7%) shelter-resident canines, and 12/103 (11.65%) shelter-resident felines. In contrast, Blastocystis was not detected in any of the pets owned by families in the study.
For details, or to view the study, follow this link to PLOS-One.
Springer-Verlag has published the world’s first major textbook on Blastocystis. The text, assembled by Parasitology Research editor Heinz Mehlhorn and long-time Blastocystis researchers Kevin Tan and Hisao Yoshikawa.
BRF co-founder Ken Boorom contributed two chapters that investigate the analytical process behind using research studies to make a decision about pathogenicity, and suggest that the difficulties associated with Blastocystis recur frequently in the medical community.
The text is sure to become a classic work in this field, and has both scientific and historical significance. It would be a valuable addition to any collection or library.
Read excerpts on Springer-Verlag’s Site, purchase there
Read excerpts on Amazon.com, purchase the text there