Kingdom: ProtistaKingdom: Protista

►Phylum: ApicomplexaPhylum: Apicomplexa►Class: ConoidasidaClass: Conoidasida►Subclass: CoccidiasinaSubclass: Coccidiasina►Order:Order: Eucoccidiorida Eucoccidiorida►Family:Family: Sarcocystidae Sarcocystidae►Genus: Toxoplasma Genus: Toxoplasma ►Species: T.gondiiSpecies: T.gondii

Toxoplasma gondiiToxoplasma gondii

T.Gondii was first T.Gondii was first discovered in 1908 discovered in 1908 in desert rodent ,the in desert rodent ,the gondi, in a colony gondi, in a colony maintained at the maintained at the Pasteur institute in Pasteur institute in Tunis.Tunis.

T. gondii constructing daughter scaffolds within the mother cell

T.gondiiT.gondii

►T.gondii is a intracellular parasite in T.gondii is a intracellular parasite in many tissues, such as intestinal many tissues, such as intestinal epithelum and muscle. epithelum and muscle.

►The organisms can be found also free The organisms can be found also free in the blood and peritoneal exudate.in the blood and peritoneal exudate.

► In the fetal life, the parasite infection In the fetal life, the parasite infection can lead to death (Human & sheep)can lead to death (Human & sheep)

Definitive hostDefinitive host

►Mainly domestic and wild cats.Mainly domestic and wild cats.►Cats can become infected by ingesting Cats can become infected by ingesting

sporulated oocyst or infected rodent or sporulated oocyst or infected rodent or a bird.a bird.

Intermediate hostIntermediate host

►Human, cattle, birds, rodents, pigs, Human, cattle, birds, rodents, pigs, and sheep.and sheep.

►Humans get the disease through Humans get the disease through ingestion of a cyst, infected raw meat, ingestion of a cyst, infected raw meat, transplacental, organ transplatantion transplacental, organ transplatantion or blood transfusion.or blood transfusion.

Life cycleLife cycle

►The protozoa multiplies sexually in the The protozoa multiplies sexually in the

cat’s intestinal and asexually in a cat’s intestinal and asexually in a many mammals and even birds.many mammals and even birds.

►Cats are infected by eating infected Cats are infected by eating infected rodent.the zoitocyst which contains rodent.the zoitocyst which contains bradyzoites travel to the intestine via bradyzoites travel to the intestine via digestive tract. digestive tract.

Cont. life cycleCont. life cycle

►Bradyzoites are released in the Bradyzoites are released in the intestine.intestine.

►Bradysoites infect cells and become Bradysoites infect cells and become trophozoites.trophozoites.

►Fertilization ocurres in the intestine and Fertilization ocurres in the intestine and immature oocyst are passed in the cat’s immature oocyst are passed in the cat’s feces.feces.

►The Oocyst are contaminated with The Oocyst are contaminated with water, food and soil are ingested by water, food and soil are ingested by intermediate host.intermediate host.

The protozoa reproduces The protozoa reproduces asexually in the intermediate asexually in the intermediate

host.host.► Ingested oocyst goes to the digestive tract.Ingested oocyst goes to the digestive tract.► It is here that they are engulfed by It is here that they are engulfed by

macrophages. macrophages. ► In the macrophage tachyzoites develop and In the macrophage tachyzoites develop and

travel to various parts of the body via blood travel to various parts of the body via blood stream (Heart, spleen, liver and brain).stream (Heart, spleen, liver and brain).

► once immune response is trigered, once immune response is trigered, tachyzoites encyst into zoitocysts and tachyzoites encyst into zoitocysts and pseudocysts which contain pseudocysts which contain bradyzoites(inactive).bradyzoites(inactive).

Tachyzoite stageTachyzoite stage

Tachyzoites are typically crescent shaped with a prominent, centrally placed nucleus."

Economic impactEconomic impact

►Toxoplasma gondii has a devastating Toxoplasma gondii has a devastating economic impact on the countries who economic impact on the countries who export livestock.export livestock.

►Toxoplasmosis is leading cause of Toxoplasmosis is leading cause of abortion in sheep and goats.abortion in sheep and goats.

Geographic rangeGeographic range

►Worldwide Worldwide ► Infection is more common in warm Infection is more common in warm

climates and lower altitudes than cold climates and lower altitudes than cold climates and mountainous regions.climates and mountainous regions.

► In the U.S a survey (NHANES III) In the U.S a survey (NHANES III) between 1988 and 1994 was found to between 1988 and 1994 was found to be 22.5%, with seroprevalence among be 22.5%, with seroprevalence among women of childbearing age (15 to 44 women of childbearing age (15 to 44 years) of 15%years) of 15%

PathogenesisPathogenesis

► Infection with Infection with ToxoplasmaToxoplasma in in immunocompetent persons is generally an immunocompetent persons is generally an asymptomatic infection.     asymptomatic infection.    

► The clinical course is benign and self-limited; The clinical course is benign and self-limited; symptoms usually resolve within a few symptoms usually resolve within a few months to a year. months to a year.

► Immunodeficient patients often have central Immunodeficient patients often have central nervous system (CNS) disease but may have nervous system (CNS) disease but may have retinochoroiditis, or pneumonitis.  In patients retinochoroiditis, or pneumonitis.  In patients with AIDS, toxoplasmic encephalitis is the with AIDS, toxoplasmic encephalitis is the most common cause of intracerebral mass most common cause of intracerebral mass lesions and is thought to be caused by lesions and is thought to be caused by reactivation of chronic infection.  reactivation of chronic infection. 

PathogenesisPathogenesis

►Causes Encephalitis for Causes Encephalitis for immunosuppressed patients and people immunosuppressed patients and people infected with (AIDS).infected with (AIDS).

►Lymphadenitis is the most common in Lymphadenitis is the most common in humans.humans.

►Children exhibit Hydrocephalatus, Children exhibit Hydrocephalatus, retinochoroiditis, convulsion and retinochoroiditis, convulsion and intracerebral calsifications.intracerebral calsifications.

►Congenital neurological defects in infants.Congenital neurological defects in infants.

Severe, active retinochoroiditis

DiagnosisDiagnosis

►Biopsy of humans.Biopsy of humans.►(ELISA) Enzyme-Linked (ELISA) Enzyme-Linked

Immunoabsorbent Assays.Immunoabsorbent Assays.►(IFAT) Indirect Fluorescent Antibody (IFAT) Indirect Fluorescent Antibody

tests.tests.

TreatmentTreatment

►SulfonamidesSulfonamides►Pyrimethamine(daraprim)Pyrimethamine(daraprim)

ControlControl

►Pets should be checked and cured.Pets should be checked and cured.►Wash hands thoroughly with soupWash hands thoroughly with soup►Cats should be kept indoors and litter Cats should be kept indoors and litter

boxes changed daily.boxes changed daily.►Better cook your meat well.Better cook your meat well.►Cat feces should be flashed down the Cat feces should be flashed down the

toilet or burned.toilet or burned.

ReferenceReference

► Roberts, Larry and John Janovy. Roberts, Larry and John Janovy. Foundations Foundations of parasitology. of parasitology. Seventh edition.Seventh edition.

► http://www.dpd.cdc.gov/dpdx/HTML/Toxoplahttp://www.dpd.cdc.gov/dpdx/HTML/Toxoplasmosis.htmsmosis.htm 02/01/07 02/01/07

► http://gsbs.utmb.edu/microbook/http://gsbs.utmb.edu/microbook/ 02/01/07 02/01/07► http://cvm.msu.edu/courses/mic569/docs/pahttp://cvm.msu.edu/courses/mic569/docs/pa

rasite/TOXOrasite/TOXO 02/01/07 02/01/07

► http://www.cdfound.to.it/html/tox1.htm#tg7http://www.cdfound.to.it/html/tox1.htm#tg7 02/01/07 02/01/07

► http://www.gsbs.utmb.edu/microbook/ch084http://www.gsbs.utmb.edu/microbook/ch084.htm.htm 02/06/07 02/06/07