机会致病原虫 Opportunistic protozoa：刚地弓形虫 Toxoplasma gondii（toxoplasmosis）

Opportunistic protozoa Pathogens Disease Sites parasitized Toxoplasma gondi toxoplasmosis All cells except rBC Cryptosporidium spp. cryptosporidiosis Intestinal epithelium Isospora spp. isosporiasIs Intestinal epithelium microsporidia micros porIdIOSIS Intestinal epithelium Brain, liver, kidney.. Blastocystis hominis blastocystosis intestine Pneumocystis jeroveci Pneumocystis lung (Pneumocystis carinii)pneumonia(PCP

Opportunistic protozoa Pathogens Disease Sites parasitized Toxoplasma gondii toxoplasmosis All cells except RBC Cryptosporidiumspp. cryptosporidiosis Intestinal epithelium Isospora spp. isosporiasis Intestinal epithelium microsporidia microsporidiosis Intestinal epithelium Brain, liver, kidney… Blastocystis hominus blastocystosis intestine Pneumocystisjeroveci (Pneumocystis carinii) Pneumocystis pneumonia (PCP) lung

ToXoplasma gondi (toxoplasmosis

Toxoplasma gondii (toxoplasmosis)

Introduction ToXoplasma gondii has very low host specificity, and it will probably infect almost any mammal. It invades all kinds of cells except RBC Cats (both domestic and wild) are the only definitive hosts and can also be the intermediate hosts The disease that ToXoplasma gondii caused (toxoplasmosis) has been found in virtually every country of the world Toxoplasmosis is a significant cause of morbidity and mortality in AIDS patients and congenitally infected infants--opportunistic infection for human

• Toxoplasma gondii has very low host specificity, and it will probably infect almost any mammal. It invades all kinds of cells except RBC • Cats (both domestic and wild) are the only definitive hosts and can also be the intermediate hosts • The disease that Toxoplasma gondii caused (toxoplasmosis) has been found in virtually every country of the world • Toxoplasmosis is a significant cause of morbidity and mortality in AIDS patients and congenitally infected infants -- opportunistic infection for human Introduction

Morphology Trophozoite The intracellular parasites( tachyzoite速殖子)are 3X6um, crescent shaped organisms that are enclosed in a cell membrane to form a pseudocyst(假包囊) measuring 10-100 um in size Toxoplasma gondii tachyzoites (by P.w. Pappas and S.M. Wardrop)

Morphology • Trophozoite – The intracellular parasites (tachyzoite速殖子) are 3x6µm, crescent shaped organisms that are enclosed in a cell membrane to form a pseudocyst (假包囊) measuring 10-100 µm in size

Morphology Pseudocyst intracellular tachyzoites of ToXoplasma gondii

Morphology • Pseudocyst -- intracellular tachyzoites of Toxoplasma gondii

Morphology A cyst(包囊)of ToXoplasma gondii Toxoplasma gann filled with bradyzoites (by P.W. Pappas arld S.M. Wardrop) cyst in cardiac muscle

Morphology • A cyst (包囊)of Toxoplasma gondii filled with bradyzoites; cyst in cardiac muscle

Cyst in brain

Cyst in brain

Morphology A sporulated oocyst(卵囊) of ToXop/ asma gondii The oocyst contains two sporocysts(孢子囊),each of which contain four crescent-shaped sporozoites (子孢子) Only cats produce and pass ToXoplasma oocysts approximate diameter 10 um 了 oXoplasma gond oocyst (by P W. Pappas and S.M. Wardrop))

Morphology • A sporulated oocyst (卵囊)of Toxoplasma gondii. • The oocyst contains two sporocysts(孢子囊), each of which contain four crescent-shaped sporozoites (子孢子) • Only cats produce and pass Toxoplasma oocysts; approximate diameter = 10 µm

Life Cvcle Fecal A Tissue Cysts Both oocysts and tissue cysts transform into tachyzoites shortly after ingestion Tachyzoites localize in neural and muscle tissue and develop into tissue cyst bradyzoites. If a pregnant woman becomes infected, tachyzoites can infect the fetus via the bloodstream △= Infective Stage A Diagnostic Stage A A a Diagnostic Stage 1)Serological diagnosis 2)Direct identification of the parasite from peripheral blood, amniotic fluid, or in tissue sections

Life Cycle