1. INFECTIOUS DISEASE OF
PATHOLOGY
(Protozoal Diseases)
Toxoplasmosis
Dr. Naila Awal

2. • Causative organism- Toxoplasma gondii
• Toxoplasma comes from- Toxo & Plasma
Toxo bow shaped.
.
• Forms of toxoplasmaIt’s a bow shaped parasite
1) Tachyzoite-Most common infected form.
2) BradyzoitePresent in tissue cyst.
3) Oocyst

3. Mode of Transmission
• Tissue cyst containing bradyzoite
.Ex- Ingestion of infected undercooked meat- e.g-Sushi
Organ transplantation
• Tachyzoite infection-
Ex- Meat handler / Butcher
Handling infected cat
Handling of culture media of toxoplasma
Transpalcental route
• Oocyst infection- by contaminated food & drink.

4. Clinical presentation
• Acute toxoplasmosis- May be asymptomatic
1) Flu like syndrome- Fever, sore throat, rhinitis
2)Lymphadenopathy- most commonly posterior cervical
lymph node.
3)Occasional rash

5. Congenital toxoplasmosis- Very dangerous
Sign1) Coroido- retinitis- Parasite multiply within choroid
Inflammation of retina Mild illumination of vision to
blindness.
2)Microcephaly / Hydrocephalus
3)Calcification of cerebral ventricle.
4)Convulsion

6. Diagnosis of Toxoplasmosis
Acute toxoplasmosis-
Specimen1) Lymph node biopsy
2) Bone marrow aspiration
3)CSF
5) Peritoneal fluid
4)Broncho alveolar lavage
Lab procedure1) Direct microscopy- Smear is taken in a glass slide air dry
Leishman/ Giemsa stain
Findings- Tachyzoite
2) Culture- Specimen is inocculated in –
•
corio-allantoic membrane of embryonated cheek egg/
•
lab animal-mice incubate Observation.
Observation- Bradyzoite.

7. Congenital toxoplasmosis
1)
Serology (Mother)- It is the best test for toxoplasmosis.
Ig G
+
Ig M
+
Possibility
of transmission to
Fetus
Patient is never infected with toxoplasmosis
Patient got infected
1yr before
Boderline +
Repeat after 2 weeks
Strongly +
Toxoplasma +
Boderline+/Toxoplasma –

8. 2) Amniocentesis- For detection of DNA of toxoplasma.
3) Associated test TC of WBC- Leukocytosis
DC- Lymphocytosis with atypical mononuclear cell.
Fate of fetus
1)
2)
Spontaneous abortion
Congenital malformation.

9. Diagnosis of toxoplasmosis in HIV positive
patient
By Ig G titer.
• Ig G titer is used for diagnosis of reactivation
of tissue cyst in HIV positive patient.
• If Ig G titer is increased 16 folds
Toxoplasmosis

10. Histological findings
Lymph nodePoster cervical lymph nodes commonly affected.
• Findings1) Folicular hyperplesia with intense mitotic activity.
2) Reactive follicles are surrounded by small granuloma,
composed of epithelioid cells. Rarely necrosis & Langhan’s
giant cell are present.
EyeFocal area of coagulation necrosis of retina surrounded by
granulomatous inflammation in adjacent choroid & retina.
Within necrotic retina- cyst of Toxoplasma can be found.

11. Lymph node
•
Epithelioid granuloma
•
Follicular hyperplesia

12. Indication of abortion in toxoplasmosis
1) If fetal infection is confirmed within 22weeks of
gestation Induced abortion.
2)If mother is seroconvert within the 3 months
Terminate the pregnancy.