INFECTIOUS DISEASE OF PATHOLOGY

(Protozoal Diseases)Toxoplasmosis

Dr. Naila Awal

• Causative organism- Toxoplasma gondii• Toxoplasma comes from- Toxo & PlasmaToxo bow shaped.

It’s a bow shaped parasite. • Forms of toxoplasma-1) Tachyzoite-Most common infected form.2) Bradyzoite-Present in tissue cyst.3) Oocyst

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.

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

Congenital toxoplasmosis- Very dangerous

Sign-1) Coroido- retinitis- Parasite multiply within choroid

Inflammation of retina Mild illumination of vision to blindness.

2)Microcephaly / Hydrocephalus3)Calcification of cerebral ventricle.4)Convulsion

Diagnosis of ToxoplasmosisAcute toxoplasmosis-

Specimen-1) Lymph node biopsy 3)CSF 5) Peritoneal fluid 2) Bone marrow aspiration 4)Broncho alveolar lavage

Lab procedure-1) 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.

Congenital toxoplasmosis

1) Serology (Mother)- It is the best test for toxoplasmosis. Ig G + - Ig M Patient is never infected with toxoplasmosis

+ - Boderline +

Possibility Patient got infected Repeat after 2 weeksof transmission to 1yr beforeFetus Strongly + Boderline+/- Toxoplasma + Toxoplasma –

2) Amniocentesis- For detection of DNA of toxoplasma.

3) Associated test- TC of WBC- LeukocytosisDC- Lymphocytosis with atypical mononuclear cell.

Fate of fetus1) Spontaneous abortion

2) Congenital malformation.

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

Histological findingsological findings

Lymph node-Poster cervical lymph nodes commonly affected.• Findings-1) 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.

Eye-Focal area of coagulation necrosis of retina surrounded by

granulomatous inflammation in adjacent choroid & retina.Within necrotic retina- cyst of Toxoplasma can be found.

Lymph node• Epithelioid granuloma

• Follicular hyperplesia

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.