Toxoplasma gondii(toxoplasmosis)
Toxoplasma gondii (toxoplasmosis)
Introduction. Toxoplasma gondii has very low hostspecificity, and it will probably infectalmost any mammal. It has also beenreported from birds, and has been found invirtually every country of the world. Likemost of the Apicomplexa, Toxoplasma is anobligate intracellular parasite. Its life cycleincludes two phases called the intestinal (orenteroepithelial) and extraintestinal phases
• 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. Like most of the Apicomplexa, Toxoplasma is an obligate intracellular parasite. Its life cycle includes two phases called the intestinal (or enteroepithelial) and extraintestinal phases. Introduction
: The intestinal phase occurs in cats only (wild aswell as domesticated cats) and produces"oocysts." The extraintestinal phase occurs in allinfected animals (including cats) and produces"tachyzoites" and, eventually, "bradyzoites"or"zoitocysts." The disease toxoplasmosis can betransmitted by ingestion of oocysts (in cat fecesor bradyzoites (in raw or undercooked meat)
• 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)
In most humans infected with Toxoplasma,thedisease is asymptomatic. However, under someconditions, toxoplasmosis can cause seriouspathology, including hepatitis, pneumonia.blindness, and severe neurological disorders. Thisis especially true in individuals whose immunesystems are compromised (e.g., AIDSpatients). Toxoplasmosis can also be transmittedtransplacentally resulting in a spontaneousabortion, a still born, or a child that is severelyhandicapped mentally and/or physically
• In most humans infected with Toxoplasma, the disease is asymptomatic. However, under some conditions, toxoplasmosis can cause serious pathology, including hepatitis, pneumonia, blindness, and severe neurological disorders. This is especially true in individuals whose immune systems are compromised (e.g., AIDS patients). Toxoplasmosis can also be transmitted transplacentally resulting in a spontaneous abortion, a still born, or a child that is severely handicapped mentally and/or physically
MorphologyThe intracellularToxoplasma gondiiparasites(tachyzoite)are3x6u, crescent shapedorganisms that aretachyzoitesenclosedinaparasitemembraneto form a cystmeasuring 10-100 μin(byP.W.Pappasand S.M.Wardrop)size.Cysts incatfeces(o0cysts)are10-13μindiameter
Morphology • The intracellular parasites (tachyzoite) are 3x6µ, crescent shaped organisms that are enclosed in a parasite membrane to form a cyst measuring 10-100 µin size. Cysts in cat feces (oocysts) are 10-13 µin diameter