 BLOOD, BONE MARROW, SPLEEN,
LYMPHNODE, 
CNS AND EYE PARASITES
SPOROZOEA Order: Eucoccidiida
TOXOPLASMA GONDII
tg1-ic
Toxoplasma gondii: life cycle.
tg2-ic
T. gondii: T.gondii
encephalitis (TE) is the most common cerebral
opportunistic infection in patients with AIDS.
The typical lesion is an ipodense focal area with ring
contrast-enhancement and edema.
(CT scan of a toxoplasmic encephalitis).
tg3-ic
T. gondii: tissue cysts, 100-300
µm, may contain up to 3.000 bradyzoites.
The wall of mature pseudocysts is believed to represent
a combination of host and parasitic components.
tg4-ic
T. gondii: diagnosis of TE is
usually presumptive,
based on clinical and radiologic findings and on the response to treatment;
cerebral biopsy sometimes allows identification of pseudocysts in tissue sections.
(H&E stain).
tg4b-ic
T. gondii: toxoplasmic pseudocyst
within an inflammatory tissue reaction.
(H&E stain).
T. gondii: lymphodes
in Toxoplasma infection usually show expanded
germinative centers surrounded by abundant perifollicular epithelioid
cells.
Protozoa are not commonly seen in sections, except in immunocompromised
hosts:
the patient (a 19 year old caucasian male) is in good health condition,
without history of inherited or acquired immunodeficiency, hence this
finding
(a 16 micron pseudocysts in subcutaneous tissue of a otherwise normal
scalp skin)
is occasional and rather infrequent.
tg5-ic
T. gondii: the pseudocysts of T.gondii
can be observed in tissue
sections with monoclonal antibodies.
tg6-ic
T. gondii: direct detection of T.gondii
in clinical specimens is rare;
parasites can be isolated from blood, CSF, amniotic fluid,
tissue biopsies on cell lines (THP-1 or MRC-5).
In clinical specimens the presence of parasites can also
be demonstrated by PCR analysis.
tg7-ic
T. gondii: intracellular
trophozoites of T.gondii in a cell culture.
The trophozoites proliferate within the vacuole developing a pseudocyst.
(Trophozoites in a THP-1 cell, Giemsa stain).
tg8-ic
T. gondii: in cell cultures T.gondii
proliferates to form a pseudocyst of 8-20 parasites.
(Trophozoites in a THP-1 cell, Giemsa stain).
tg9-ic
T. gondii: lysis of a THP-1 cell
with release of tachizoites in culture.
(Trophozoites in a THP-1 cell, Giemsa stain).
tgcareggi-ic
T. gondii: :
intracellular trophozoites of T.gondii in a cell
culture
of human fibroblasts (MRC-5). The parasite was isolated from amniotic
fluid.
tg10-ic
T. gondii: microscopical
features of tachizoites of Toxoplasma gondii
and peritoneal macrophages of mouse in peritoneal exudate. (SEM)
tg11-ic
T. gondii: microscopical
features of tachizoites of Toxoplasma gondii
and peritoneal macrophages of mouse in peritoneal exudate. (SEM)
tg12-ic
T. gondii:
the anterior pole of an endozoid in tangential projection.
Several subpellicular fibrils and their insertion on
the anterior polar ring are visible.
tg13-ic
T. gondii:
transmision electron microscopic picture.
Longitudinal section of an endozoid.
tg14-ic
T. gondii:
cross-section through an endozoid
in an advanced stage of endodiogeny.
The daugther cells appear to be surrounded.
In each of these news cells there are two round bodies
that lengthen forming the first rhoptries.
EYE.... CENTRAL....BLOOD....
 
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