I understand that the cysts are difficult to eradicate, but do they cause an immune response, or is the immune response caused by the free tachyzoites?
At the beginning tachyzoites cause the acute infection. These cells estimulate the immune response and the brain cyst develop in brain and muscle. Therefore a chronic infection start and Toxoplasma antibodies remain for ever. It is why most of human toxoplasmosis are asynthomatic but antidoy presence is always detected, which confuse sometimes and induce to give some tratment. Since the toxo prevalence usually is high, it is neccesary to repeat the laboratory IgG and IgM tests (Elisa, IFA, etc.), before any treatment. If IgM is negative or present a very low title and IgG does not change more that one title, it is almos sure that we are dealing with a chonic infection that does no need treatment.
Any other question to this respect is welcome.
This is the same answer, corrected in some of the words. Thank you.
At the beginning tachyzoites cause the acute infection. These cells estimulate the immune response and the brain cyst develop in brain and muscle. Therefore a chronic infection start and Toxoplasma antibodies remain for ever. It is why most of human toxoplasmosis are asynthomatic but antidoy presence is always detected, which confuse sometimes and induce to give some tratment. Since the toxo prevalence usually is high, it is neccesary to repeat the laboratory IgG and IgM tests (Elisa, IFA, etc.), before any treatment. If IgM is negative or present a very low title and IgG does not change more that one title, it is almost sure that we are dealing with a chronic infection that does no need treatment.
Any other question to this respect is welcome.
The antibody response is generated against tachys during the acute phase (IgM), and maintained as memory response (IgG). Bradyzoites are considered silent forms, although some researchers believe that they may induce some minor local immune response.
Bradyzoites are in a cystic structure, in a way "isolated" from immune system. Response is generated if tachyzoites are liberated to the system
I think that there is some suggestion that the encysted bradyzoites may induce a chronic low-level neuroinflammation. They certainly alter the behavior of the natural host.
Tachyzoites and bradyzoites, both rise the immune response. Firs response is against tachyzoites and then when host got immunity tachyzoites turns bradyzoites to protect themselves from host immunity. When host has tissue cysts in its body it does not infected again. this type of immunity is known concomitant immunity, which host has the parasite but is immune for further infection.
I'm a psychiatrist clinician. I have a case of a man (38) who was born with jaundice, which was diagnosed as being caused by congenital toxoplasmosis. It was treated in a neonatal unit, although we don't know what with. He did well, but in early adulthood he developed some psychiatric problems some of which seem congruent with the literature on psychiatric consequences of toxoplasmosis. Eg
http://tinyurl.com/7vj5xom
http://edge.org/conversation/toxo
http://tinyurl.com/toxopsych
Recently he had his toxoplasma antibodies measured, and to my surprise the IgG was negative.
Does this eliminate the toxo hypothesis, or is it possible that the bradyzoites are still lurking in intraneuronal space, causing trouble, but not a measurable immune response?
Brain MRI was reported as normal.
Any ideas?
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