Toxoplasma gondii is an obligate intracellular parasite that can infect almost any mammal and has been found worldwide. It has a complex life cycle involving cats as the definitive host where it produces oocysts, and intermediate hosts where it produces tachyzoites and tissue cysts containing bradyzoites. Humans can be infected by ingesting oocysts from cat feces or tissue cysts in undercooked meat. While most infections are asymptomatic, it can cause serious issues in pregnant women and immunocompromised individuals like those with AIDS. Diagnosis involves serological tests or biopsy detection, and treatment consists of pyrimethamine and sulfadiazine antibiotics.

1. Toxoplasma Gondii

2. • Toxoplasma gondii has very low host
specificity, and it will probably infect
almost any mammal.
• It has also been reported from birds, and has
been found in virtually every country of the
world.
• Toxoplasma is an obligate intracellular
parasite.

3. Morphology
• Trophozoite
– oval shaped /crescent
shaped organisms
– One end is pointed and
other is blunted
– 7x7m
– Nucleus lies near blunt end
– Trophozoite invade
mammalian cells and is
called tachyzoites

4. • Tissue Cysts
– 10-200 m
– Contain thousand
of organisms
– Responsible for
transmission of
infection
– Formed during
chronic stage of
infection
• Oocytes
– Spherical / oval
– 10-12 m
– Contain sporoblast
– Freshly passed oocytes
are not infective
– Become infective after
development in soil or
water
– Oocytes develop only in
definitiv e host

5. • Life cycle is completed by two phases
– Enteric cycle in Cat
– Exoenteric cycle in man
• The intestinal phase occurs in cats only (wild as well as
domesticated cats) and produces "oocysts." The
extraintestinal phase occurs in all infected animals
(including cats) and produces "tachyzoites" and,
eventually, "bradyzoites" or "zoitocysts." The disease
toxoplasmosis can be transmitted by ingestion of oocysts
(in cat feces) or bradyzoites (in raw or undercooked
meat).
Life Cycle

7. Mode of Transmission
• Ingestion of oocyst or tissue cyst containing
edibles
• Through placenta
• Occupational
• Laboratory workers
• Slaughter house workers

8. • In most humans infected with Toxoplasma, the
disease is asymptomatic.
• Some conditions, toxoplasmosis can cause serious
pathology, including hepatitis, pneumonia, blindness,
and severe neurological disorders.
• This is especially occurs in individuals whose
immune systems are compromised (e.g., AIDS
patients).
• Toxoplasmosis can also be transmitted
transplacentally resulting in a spontaneous abortion,
a still birth, etc.
Pathogenesis

9. Symptoms
• Although Toxoplasma infection is common, it rarely
produces symptoms in normal individuals.
• Its serious consequences are limited to pregnant women
and immuno-deficient hosts.
• Which result in miscarriage, serious brain and eye
damage to the fetus, babies will have visual handicaps.
• Mental retardation in childhood or young adulthood.
• Lymphadenitis, maculopapular rash, myocarditis etc.

10. Diagnosis
• Suspected toxoplasmosis can be confirmed
by isolation of organism from tonsil or lymph
gland biopsy.
• Serological tests
• Latex agglutination test
• ELISA
• Complement fixation test
• Indirect immunoflourascence test
• Methylene blue dye test

11. Treatment
• Pyrimethamine + sulphadiazine.
• Spiramycin is a successful alternative.
• Pregnant women are advised to avoid cat
litter, handle uncooked meat carefully and
undercooked meat.

12. Thank You