Intestinal inflammation and a systemic response to bacterial antigens can develop in the absence of a measurable disruption of intestinal permeability.

A defect in epithelial barrier integrity is not required for a systemic response to bacterial antigens or intestinal injury in T cell receptor-alpha gene-deficient mice. Inflamm Bowel Dis. 2006 Aug;12(8):750-7. Sydora BC1, Tavernini MM, Doyle J, Fedorak RN.


The traditional model envisions a battle between organism and host that produces acute, usually self-limited illnesses, and the main disease manifestations are due to the presence of the microorganisms or its toxic products in a specific organ system. Recent advances in our understanding of host immune responses during microbial infection suggest that in most cases, it may be the aberrant host responses rather than the pathogen-specific toxins or oncogenes induced by the pathogen’s products that cause the disease.  Immunoregulatory Role of B7-H1 in Chronicity of Inflammatory Responses Cell Mol Immunol. 2006 June; 3(3): 179–187. 

The results with cyproheptadine (Periactin) indicate that the mast cell derived mediators, histamine and serotonin, are responsible for a major portion of the reaction. This is confirmed by the findings that SMX, a potent mast cell protector (Ferraresi, Roszkowski & Kepel, 1974) had substantial neutralizing effect on the reaction. Cromolyn sodium, a known mast cell protector, showed similar but less effective neutralizing effects. This may be related to its poor absorbtion by the oral route (Cox et al., 1970).

There have been several reports of treatment of human food allergy using cromolyn sodium (Freier & Berger, 1973; Kingsley, 1974; Breslin, Hendrick & Pepys, 1973).

In conjunction with the animal data presented above, these reports confirm the usefulness of mast cell protectors in intestinal inflammatory reactions. Intestinal anaphylaxis in the rat as a model of food allergy. Clin. exp. Immunol. Byars & Ferrares (1976) 24, 352-356.

Atarax is an antihistamine used to relieve the symptoms of common anxiety and tension and, in combination with other medications, to treat anxiety that results from physical illness.
The activation of mast cells has been known for many years to be associated with a variety of effects on the intestinal epithelium. Thus the release of mast cell mediators resulting from parasitic infestation, systemic anaphylaxis or systemic mastocytosis has been related to the development of diarrhea and malabsorption, increases in mucous secretion, epithelial damage and sloughing, villous atrophy, and crypt hyperplasia.
Immune-related intestinal
Cl-secretion. Effect of histamine on the Ts4 cell line. Wasserman et al. 1988. The American Physiological Society.

Overt mast cell degranulation is seen with food allergies and asthma. Mast cells can secrete chemicals selectively, without overt degranulation, (Theoharides and Douglas, 1978).

Unlike allergic reactions, mast cells are rarely seen to degranulate during autoimmune (Benoist and Mathis, 2002) or inflammatory processes (Woolley, 2003); Instead, mast cells appear to undergo ultrastructural alterations of their electron dense granular core indicative of secretion, but without overt degranulation, a process that has been termed;activation; (Dimitriadou et al., 1990; Dimitriadou et al., 1991; Theoharides et al., 1995a) ;intragranular activation’’ (Letourneau et al., 1996) or piecemeal degr anulation (Dvorak et al., 1992a,b). Such subtle activation may be associated with the ability of mast cells to release some mediators selectively (Kops et al.) Critical role of mast cells in inflammatory diseases and the effect of acute stress. Theoharis C. Theoharides , David E. Cochrane

The histopathological examination of caecum, colon and small intestine of B. hominis mice infected from symptommatic patients showed infiltration with inflammatory cells and tissue invasion by the parasite.
J Egypt Soc Parasitol. 2008 Aug;38(2):453-64.
Protein profile and morphometry of cultured human Blastocystis hominis from children with gastroenteritis and healthy ones. Hegazy MM, Maklouf LM, El Hamshary EM, Dawoud HA, Eida AM.

Cyproheptadine (Periactin) had an antidepressant effect demonstrated by a significant decrease in the Hamilton depression ratings.
Anorexia Nervosa. Treatment Efficacy of Cyproheptadine and Amitriptyline. Katherine Ann Halmi, MD; Elke Eckert, MD; Terence J. LaDu, MA; Jacob Cohen, PhD Arch Gen Psychiatry. 1986;43(2):177-181.

A main aspect of mast cell physiology that had been largely ignored until recently is that mast cells can secrete
mediators without overt degranulation
Theoharides and Douglas, 1978

An allergic reaction in the gastrointestinal tract can be manifested by discomfort, diarrhoea, cramps, malabsorption, and often, in addition, by systemic effects (Gerrard et al., 1973). Intestinal anaphylaxis in the rat as a model of food allergy. Clin. exp. Immunol. Byars & Ferrares (1976) 24, 352-356.

Whereas most external pathogens provoke an acute inflammatory or immune response that results in complete clearance of the microorganisms, some immunogenic agents promote an immune response that does not lead to clearance but to a persistent inflammatory process. Immunoregulatory Role of B7-H1 in Chronicity of Inflammatory Responses. Cell Mol Immunol. 2006 Jun; 3(3): 179–187. Haidong Dong and Xianming Chen.

Pathogenesis of most chronic human diseases, including chronic infections, autoimmune diseases and cancers, often involves a persistent, unresolved inflammatory response.

Immunoregulatory Role of B7-H1 in Chronicity of Inflammatory Responses. Cell Mol Immunol. 2006 Jun; 3(3): 179–187. Haidong Dong and Xianming Chen.

"My gastroenterologist said that the stomach takes its time to heal and indeed it did." (Australia 2012)


Most cases of Blasto. I've encountered over the last couple of decades have resulted in a complete cure after parasite eradication. I've documented some of these cases here.

However, for some people the symptoms can persist for weeks or months before eventually dying down. This as yet medically unrecognised phenomenon is always confined to people who have battled moderate to severe symptoms for more than 2 to 3 years. Bill is just one example:

Email. May 17, 2007

Thanks Jackie for the extra info, intially after treatment i felt shocking for about two or three weeks but then noticed a gradual improvement there after. I didn't take the second round of medication so the first lot did the job. I guess i felt so bad after the treatment that i just assumed that the drugs didnt fix the problem but each day i am getting a little better. Thank you so much. Bill

Follow up email July 2007:

Hi Jackie , just wanted to let you know that after almost 3 months since treatment by your recommended medication for Blasto i have tested negative "TWICE " !!!!!!!! It's gone after suffering for almost 8 years, gone too are the shitty symptoms that come with it.
I wish that i had visited your site immediately after being diagnosed so that i would not have spent years being prescribed FLAGYL by the doctors who quite obviously don't know anything about this bug.

"My doctor is not going to treat BH. She does not believe it is a pathogen. She is running other tests to see if there is something else, but some of those tests are repeats so I already know the answer." (Canada. May 20011)

It's very hard in the UK to find a doctor willing to treat Blasto, mine even refused to even look at my independent stool report. (UK. 2014)

In a small number of cases, even after a successful treatment, the symptoms can persist indefinitely, although often at signicantly reduced levels. This problem invariably occurs in people whose infections have been left untreated for over 2-3 years, which is not at all uncommon (see below), and where the symptoms are moderate to severe. This type of outcome is rare in patients whose infection is treated effectively within this 2-3 year frame (BadBugs data).

"My doctor is not going to treat BH. She does not believe it is a pathogen. She is running other tests to see if there is something else, but some of those tests are repeats so I already know the answer." (Canada. May 20011)

It's very hard in the UK to find a doctor willing to treat Blasto, mine even refused to even look at my independent stool report. (UK. 2014)

Lou and Sally are just two examples I've documented over the years where this problem has occurred. These emails were written two years after the triple in response to a follow up email. Both had repeatedly tested negative to Blasto. after finishing the triple therapy:


"After having suffered with that horrible bug for almost two years my symptoms are now 75% less than what they were while I was infected. Stool is normal but just a little discomfort in my stomach which seems worse on some days than others. No doctor could treat me properly and even a gastro specialist failed by using his text book treatment drugs - Flagyl. I can't believe this problem is such a big unknown to most doctors. Even though I've been blasto free for over a year I still have some symptoms but not nearly like before. Thank You, Lou.


I still have a very sensitive digestive system. I'm better but not totally cured..overall my symptoms have improved enormously since the triple. (Before that) I was given no treatment options for the intense abdo pain and sensitivity, flatulence, nausea, feeling infected , nose and throat allergies, sore lower back, joint pains, headaches, bad indigestion, burping and food intolerances and one episode of PR bleeding, frequent spells of anxiety, cloudiness and forgetfulness.

The medical term for symptoms which persist after an infection is terned 'Post Infectious IBS'. Medical science indicates that the biggest predictors for ending up with PI-IBS is duration of illness, severity of the infection and having psychiatric and cognitive symptoms including depression, foggy head, inability to concentrate etc.

I suffered all of these symptoms (and more), and had I been aware of the important role of the inflammatory immune response in parasitic infections, I could have predicted the outcome of my own seven long years of unncessary suffering.

In my case eliminating B.hominis and D.fragilis significantly reduced the intensity of the awful symptoms, my food intolerances improved and I regained 15 kilos - but it was far from a cure. It took me 7 more years to formulate a reasonable explanation for why I never fully regained my health, and why I fell so ill in the first place.

I learnt that parasites can trigger a complex set of immune responses which, if left for too long, can lead to a persistent continued inflammatory process after the parasite has been eradicated. Typically, I was never warned about the inherent risk of playing unwilling host to two GI parasites for several years, and after nearly two decades managing BadBugs I've never heard from anyone else who has either.

"My advice to anyone with a GP who says IBS? Tell them to Fuck off. I've had symptoms for 18 months but they were consistent and I knew something was up. I'm otherwise healthy, not depressed or anxious or stupid, I know when I'm being fobbed off by ignorant fools. I put up with it for a while but got very angry with my GP last week, finally had some stool tests done after having an expensive CT scan and other tests. The result: B hominis. So relieved to know there are options and people who take it seriously." USA May 2011.

Why all roads don't lead to Rome.

In my search for disorders of the immune system related to parasitic infections I came across Systemic Mastocytosis (SM). There is no known cause and no cure for SM, but there is an overlap in the symptoms of SM, D.fragilis, Blasto., and IBS:

Abdominal cramping/discomfort, nausea, vomiting, fatigue, food intolerances, feeling faint, vertigo, faintness, rapid heart rate, headache, malabsorption, increased susceptibility to chest colds and 'flu, hives or other rashes, cognitive and psychiatric symptoms including irritability, depression, changes in mood, brain fog, concentration, learning, retention or anything relying on memory or information processing skills. (Mastocytosis Society Canada).

The symptoms of SM are triggered by misbehaving mast cells.

Mast Cells and Their Important Role in Parasitic Infections:

Mast cells are more well known for their harmful effects during inflammatory conditions such as asthma and allergy. However, the role of mast cells in GI infections has largely been ignored which is interesting because this reaction seems to have evolved as a defense system against intestinal worm infestations (Mixed Organic Brain Syndrome as a Manifestation of Systemic Mastocytosis. Psychosomatic Medicine Vol. 48, No. 6 (July/August 1986).

Mast cells are white blood cells which contain pharmacologically active granules. Located in various parts of the body, including abundantly in the gastrointestinal tact, mast cells are considered the sentinels of the immune system. When a mast cell encounters a bacteria or parasite it perceives as an invader it releases (degranulates) active chemicals - chemicals which induce many of the same symptoms experienced during a D.fragilis and Blasto. infection.

Research now points to these cells being involved in the pathogenic responses that makes us chronically unwell during infection. This is in contrast to the traditional picture of a battle between the organism and the host that produces symptoms due to the toxic effects of the organism.

Other research points to this immune response leading to persistent inflammation after eradication of the offending organism.

If this is the case, it means that the whole medical approach to diagnosing and treating D.fragilis and Blasto. is almost certainly placing the long term health of patients at risk.

What's more treatments which can dampen down these left-over symptoms are not being routinely prescribed to patients who end up in this state.

Some drugs to treat immune problems are easy to obtain, but others are almost impossible to get hold of - depending on where you live. Read how I discovered, and tried, these treatments here.

Systemic viral, bacterial, or parasitic infection may stimulate the immune system and cause improper activation or inflammatory changes.

(Medscape, 2012)

Recent advances in the realm of autoimmunity have made it clear that mast cells are involved in the pathogenic responses that exacerbate disease. Biochim Biophys Acta. 2011 Feb 25. New insights into the role of mast cells in autoimmunity: Evidence for a common mechanism of action? Walker ME, Hatfield JK, Brown MA.

(Mast cells) contribute to pathologic allergic inflammation but also serve an important protective role in bacterial and parasite infections. Given the proinflammatory nature of autoimmune responses, it is not surprising that studies using murine models of autoimmunity clearly implicate mast cells in the initiation and/or progression of autoimmune disease. J Immunol. 2007 Sep 1;179(5):2673-9. The multitasking mast cell: positive and negative roles in the progression of autoimmunity. Christy AL, Brown MA.

There is a rapidly growing body of evidence to support an etiological role for gastrointestinal infection and the associated immune activation in the development of post-infectious IBS Bugs and irritable bowel syndrome. The good, the bad and the ugly. J Gastroenterol Hepatol. 2010. Ghoshal et al

Interesting FAQs about mast cells:

Treatments for Mast Cell disorders.

More info. about mast cell treatments in My Story 2

More about the consequences of misdiagnosis here.