We have reviewed the records of 65 symptomatic patients with B hominis in their stool. We conclude that B hominis is a potential pathogen that may or may not require drug therapy depending on the overall clinical circumstances, the severity of symptoms, and the presence of other pathogenic organisms.
Blastocystis hominis--a potential intestinal pathogen.
R R Babb and S Wagener
West J Med. 1989 November; 151(5): 518-519.


The search for (Blastocystis hominis) should be a parasitological routine analysis since it is the cause of frequent intestinal disorders.
Ponce de Leon P, Svetaz MJ, Zdero M. Rev Latinoam Microbiol. 1991 Apr-Sep;33(2-3):159-64

The most usual complaint of Blastocystosis patients is of intense abdominal discomfort accompanied by pain. Diarrhoea is not standard, and constipation is common. The symptoms gleaned from the literature include abdominal pain, discomfort, anorexia, bloating, cramps, diarrhoea, constipation, alternating diarrhoea and constipation, watery diarrhoea, mucus diarrhoea, vomiting, dehyratation, sleeplessness, nausea, weight loss, inability to work, lassititude, dizziness, flatus, pruritis, and tenesmus. Blood in the stool as well as excessive mucus and leucocytes have been reported. Moderate to severe eosinophilia is not uncommon and was reported in 8 of 19 patients in one study.
Blastocystis hominis - Past and Future. Charles H. Zierdt. Clinical Micro. Reviews. Jan 1991, p. 61-79.

The clinician should be aware of B.hominis as a possible cause of diarrhoea and other symptoms, particularly when the parasite burden is high.
Clinical Relevance of Blastocystis hominis. Lancet June 2, 1984

B. hominis has been reported in patients with intestinal symptoms, intestinal obstruction due to carcinoma, in AIDS patients with diarrhoea, and in patients with Irritable Bowel Syndrome.
Letter to the editor.
British Journal of Biomedical Science 2001; 58:129-130
Windsor, MacFarlane, Whiteside, Chalmers, Thomas & Joynson.

We believe this case provides further evidence to support the pathogenicity of B. hominis.
Hemorrhagic Proctosigmoiditis and Blastocystis hominis infection
Annals of Internal Medicine.
Volume 124(2) Jan. 15, 1996. 278-279

Blastocystis hominis is increasingly recognized to be a cause of human enteric disease, with symptoms often like those in giardiosis.
Lipid Peroxidation Level in Patients with Blastocystosis
Eser Kiliç*, Süleyman Yazar**, Recep Saraymen, Inönü Üniversitesi Tip Fakültesi Dergisi 10(1) 1-3 (2003)


Blastocystis hominis can cause terminal ileitis in patients, without any apparent predisposing factors.
Crohn's Disease and Infections: A Complex Relationship. Medscape/WebMD. 2005

Symptoms commonly attributed to infection with B. hominis
are nonspecific and include diarrhea; abdominal pain, cramps,
or discomfort; and nausea. Profuse,
watery diarrhea has been reported in acute cases, although this may be less pronounced in chronic cases. Fatigue, anorexia, flatulence, and other nonspecific gastrointestinal
effects also may be associated with B. hominis infection. Fever has been reported, particularly in acute cases, but has not been noted in other studies. Other signs and symptoms sometimes reported include fecal leukocytes, rectal bleeding, eosinophilia, hepatomegaly and splenomegaly, cutaneous rashes, and itching. One report has indicated that joint pains
and swelling may result from infection of the synovial fluid by
B. hominis.
Blastocystis hominis Revisited
Stenzel & Boreham.
Clinical Micro. Reviews.
Oct. 1996, Vol. 9, No. 4. p. 563–584


The search for (Blastocystis hominis) should be a parasitological routine analysis since it is the cause of frequent intestinal disorders.

Ponce de Leon P, Svetaz MJ, Zdero M. Rev Latinoam Microbiol. 1991

It's seems incredible that I've been sick for so long Jackie but I could not get anyone in Perth to believe that I had a parasite. I always new it was some sort of bug but trying to convince gastroenterologists of that was near impossible. One gastro told me even if I did have (Blasto), it wasn't a pathogen. Sound familiar? I've lost my job, I've had no life and I know you have suffered the same. (Blasto. was diagnosed after 5 years of life-altering symptoms. Australia. July 2016)

After having symptoms for about 5 years now I finally found a doctor that considered the possibility of intestinal parasites and have since been diagnosed with Blasto. It feels like I am dying a slow death. (September 2005, USA)

 

Thank you very much for maintaining the Bad Bugs site.  As you are aware Blasto is soul destroying and even more so because GP's don't seem to understand. It is helpful to know that it is not just me.  Your site has given me hope. (October 2014, Australia.)


Symptoms Blasto. hominis:

The most common symptoms reported with B. hominis infection include diarrhoea, nausea, abdominal pain, cramps, discomfort and flatulence. Other less frequently reported symptoms include fever, constipation, vomiting, eosinophilia, anorexia, fatigue and non-specific gastrointestinal effects. D. fragilis and B. hominis: neglected human protozoa. J. J. Windsor. The Biomedical Scientist. July 2007. Pages 524-27.

Other symptoms reported to this site:

  • Cravings and sensitivies to sweet/starchy foods.=
  • Thickly coated tongue.
  • Undigested food particles in stool, mushy stool, diarrhoea/chronic constipation;
  • Nervous and sensory disorders including inability to concentrate, depression, panic attacks, brain fog, sleep disturbances, depression, feelings of doom.
  • Chronic fatigue.
  • Hot sweats.
  • Frequent urination.
  • Burping.
  • Rashes.
  • Feeling ill/unwell.
  • Muscle pain (less common).
  • Constipation or mushy stools. Diarrhoea is less common esp. in chronic cases.
  • Rectal itching.
  • Cessation of periods or irregular periods.
  • Burning sensation in bowel (less common).

"Currently struggling against GP, specialist and pathologist who all insist blasto is commensal and I "just" have IBS, despite the positive result for Blasto. Naturally they also put me on Flagyl for a week which resulted in feeling worse and the Blasto being completely unaffected*." (October '13. Australia) *evidenced by stool samples.


More from the scientific literature:

Purged stools from 389 patients were evaluated microscopically for the presence of Blastocystis hominis. B. hominis was the only intestinal parasite present in 23 (6%) of these patients. Of the 23 patients, 19 had symptoms which included abdominal discomfort (15 patients), anorexia (10 patients), diarrhea (9 patients), and flatus (9 patients). The remaining four patients were asymptomatic. Association of Blastocystis hominis with signs and symptoms of human disease. Sheehan DJ, Raucher BG, McKitrick JC. J Clin Microbiol. 1986 Oct;24(4):548-50.

 

Two apparently healthy children from the same family were found to have moderate to heavy Blastocystis hominis in their stool samples whilst being investigated for intestinal symptoms:
sporadic, painless, rectal bleeding in one and persistent diarrhea in the other.
Blastocystis hominis in two children of one family. West Indian Med J 1990 Mar;39(1):57-8 . Bratt DE, Tikasingh ES.

 

We describe a unique case of severe Blastocystis hominis infection in an elderly man with severe dehydration, marked leukocytosis and hypoalbuminaemia after antibiotic treatment for right pneumonia. The patient recovered after treatment with metronidazole. This case presentation demonstrates the ability of B. hominis to induce severe gastrointestinal manifestations and general deterioration, particularly in light of the controversy surrounding its possible potential pathogenicity.
Severe Blastocystis hominis in an elderly man. J Infect 1996 Jul;33(1):57-9 Arch Intern Med 1988 May;148(5):1064

 

We describe the case of a ten year-old girl who was admitted to our hospital for diarrhea, abdominal pain and fever . The presence of B. hominis was demonstrated in her stools. The patient responded favourably to treatment with metronidazole. We feel that our observation is an additional support to recognition of B. hominis as a human pathogen.
Minerva Pediatr 1996 Dec;48(12):571-3 Blastocystis hominis infection: a case report. Antonelli F et al.

 

The most usual complaint of blastocystis patients is of intense abdo. discomfort accompanied by pain. Diarrhea is not standard, and constipation is common. The symptoms gleaned from the literature include abdo. pain, discomfort, anorexia, bloating, cramps, diarrhea, constipate, alternating diarrhea and constipation, watery diarrhea, mucus diarrhea, vomiting, dehydration, sleeplessness, nausea, weight loss, inability to work, lassitude, dizziness, flatus, pruritus, and tenesmus.
Blood in the stool as well as excessive mucus and leukocytes have been reported. Moderate to severe eosinophilia is not uncommon and was reported in 8 of 19 patients in one study.
Blastocystis hominis - Past and Future. Clin. Micro. Reviews. Jan 1991 p. 61-79

 

Twenty-nine patients were asymptomatic (59%), and 20 had symptoms of bloating, flatulence, soft/loose stools, or constipation.
Blastocystis hominis in hospital employees. Am J Gastroenterol 1992 Jun;87(6):729-32

 

Of the 23 patients, 19 had symptoms which included abdominal discomfort (15 patients), anorexia (10 patients), diarrhea (9 patients), and flatus (9 patients). Association of Blastocystis hominis with signs and symptoms of human disease. J Clin Microbiol 1986 Oct;24(4):548-50

 

The most frequent symptomatology in patients with B. hominis only was: abdominal pains, pruritus, flatulence, malaise, anorexia and diarrhea. Only 14.9% did not present any symptoms at all. Isolate resistance of Blastocystis hominis to metronidazole (Flagyl). Trop Med Int Health 1999 Apr;4(4):274-7

 

The clinical picture of B. hominis consists of non specific abdominal pain, watery diarrhea, anorexia, vomiting and weight loss. Rarely, a more invasive form of the disease with rectal bleeding can occur. Blastocystis hominis infection: a case report. Minerva Pediatr 1996 Dec;48(12):571-3

 

A study at the Children's Hospital of Pittsburgh in the USA in 1993 found that 85% of children infected with Blasto. experienced gastrointestinal symptoms, including abdominal pain, diarrhoea, vomiting, and weight loss. Seventy-five percent of these children had been exposed to well water or had travelled to third-world countries. Prevalence and characteristics of Blastocystis hominis infection in children. Clin Pediatr (Phila) 1993 Feb;32(2):91-6

 

A 9 month survey carried out on 39 children in a hospital in Kuwait found abdo. pain or discomfort with or without diarhoea was present in 32 children. Only three of the children were diagnosed with other parasites. Fourteen cases diagnosed as acute experienced cramp-like diarrhoea, watery diarrrhoea and vomiting. J Trop Med Hyg 1991 Apr;94(2):118-22. Blastocystis hominis infection in children.

 

A study of 49 hospital employees in New York infected with Blastocystis hominis - 59% were asymptomatic. The remaining 41% experienced bloating, flatulence, soft/loose stools, or constipation. Am J. Gastroenterology 1992 June;87(6):729-32. Blastocystis hominis in hospital employees.

 

Fifty-two patients at a teaching hospital in the US found without concomitant parasitic infection or bacterial pathogens in stool experienced gastrointestinal symptoms. The highest reported symptom was abdominal pain, diarrhea and five patients experienced vomiting. In 50 of these patients Blasto only was identified in stool samples. J Clin Gastroenterol 1990 Oct;12(5):525-32. Frequency of recovery of Blastocystis hominis in clinical practice.

 

Of 143 at a Canadian hospital where B.hominis was the only parasite found:
19 patients were asymptomatic
15 had symptoms of acute gastroenteritis
21 had chronic gastroenteritis
One hundred and thirty of these patients reported watery diarrhoea, abdo. pain and gas.
J Clin Microbiol 1990 Jan;28(1):116-21. Epidemiology and pathogenicity of Blastocystis hominis.

 

Symptoms of B. hominis in a hospital in Saudi Arabia found the most common symptoms were abdominal pain (87.9%), constipation (32.2%), diarrhea (23.4%), alternating diarrhea and constipation (14.5%), vomiting (12.5%), and fatigue (10.5%).
Clinical significance of Blastocystis hominis. Qadri SM, al-Okaili GA, al-Dayel F. Department of Pathology, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia

We have reviewed the records of 65 symptomatic patients with B hominis in their stool. We conclude that B hominis is a potential pathogen that may or may not require drug therapy depending on the overall clinical circumstances, the severity of symptoms, and the presence of other pathogenic organisms.
Blastocystis hominis--a potential intestinal pathogen. R R Babb and S Wagener West J Med. 1989 November; 151(5): 518-519.

 

The most usual complaint of Blastocystosis patients is of intense abdominal discomfort accompanied by pain. Diarrhoea is not standard, and constipation is common. The symptoms gleaned from the literature include abdominal pain, discomfort, anorexia, bloating, cramps, diarrhoea, constipation, alternating diarrhoea and constipation, watery diarrhoea, mucus diarrhoea, vomiting, dehyratation, sleeplessness, nausea, weight loss, inability to work, lassititude, dizziness, flatus, pruritis, and tenesmus. Blood in the stool as well as excessive mucus and leucocytes have been reported. Moderate to severe eosinophilia is not uncommon and was reported in 8 of 19 patients in one study.

Blastocystis hominis - Past and Future. Charles H. Zierdt. Clinical Micro. Reviews. Jan 1991, p. 61-79.

The clinician should be aware of B.hominis as a possible cause of diarrhoea and other symptoms, particularly when the parasite burden is high. Clinical Relevance of Blastocystis hominis. Lancet June 2, 1984

 

B. hominis has been reported in patients with intestinal symptoms, intestinal obstruction due to carcinoma, in AIDS patients with diarrhoea, and in patients with Irritable Bowel Syndrome. Letter to the editor. British Journal of Biomedical Science 2001; 58:129-130 Windsor, MacFarlane, Whiteside, Chalmers, Thomas & Joynson.

 

The clinician should be aware of B.hominis as a possible cause of diarrhoea and other symptoms, particularly when the parasite burden is high. Clinical Relevance of Blastocystis hominis. Lancet June 2, 1984

 

We believe this case provides further evidence to support the pathogenicity of B. hominis. Hemorrhagic Proctosigmoiditis and Blastocystis hominis infection. Annals of Internal Medicine. Volume 124(2) Jan. 15, 1996. 278-279

 

Loose stools, diarrhea, stomach pain, and stomach cramping are the most common symptoms. Loss of weight and appetite, nausea, and fatigue also are common symptoms. Center for Disease Control website on D.fragilis

 

Blastocystis hominis is increasingly recognized to be a cause of human enteric disease, with symptoms often like those in giardiosis. Lipid Peroxidation Level in Patients with Blastocystosis. Eser Kiliç, Süleyman Yazar, Recep Saraymen, Inönü Üniversitesi Tip Fakültesi Dergisi 10(1) 1-3 (2003)

 

Blastocystis hominis can cause terminal ileitis in patients, without any apparent predisposing factors. Crohn's Disease and Infections: A Complex Relationship. Medscape/WebMD. 2005

 

Symptoms commonly attributed to infection with B. hominis are nonspecific and include diarrhea; abdominal pain, cramps, or discomfort; and nausea. Profuse, watery diarrhea has been reported in acute cases, although this may be less pronounced in chronic cases. Fatigue, anorexia, flatulence, and other nonspecific gastrointestinal effects also may be associated with B. hominis infection. Fever has been reported, particularly in acute cases, but has not been noted in other studies.

Other signs and symptoms sometimes reported include fecal leukocytes, rectal bleeding, eosinophilia, hepatomegaly and splenomegaly, cutaneous rashes, and itching. One report has indicated that joint pains and swelling may result from infection of the synovial fluid by B. hominis.

Blastocystis hominis Revisited Stenzel & Boreham. Clinical Micro. Reviews. Oct. 1996, Vol. 9, No. 4. p. 563–584