TOXOPLASMOSISTOXOPLASMOSIS

Dr.T.V.Rao MDDr.T.V.Rao MD

Human ToxoplasmosisHuman Toxoplasmosis

Toxoplasmosis is a Toxoplasmosis is a zoonotic diseasezoonotic disease

Caused by Caused by Coccidian Coccidian protozoan protozoan Toxoplasma gondiiToxoplasma gondii

Infectes a wide Infectes a wide range of animals, range of animals, birds but does not birds but does not appear to cause appear to cause disease in themdisease in them

ToxoplasmosisToxoplasmosis(TOX-o-plaz-MO-sis(TOX-o-plaz-MO-sis))

A disease of the blood and lymphatic A disease of the blood and lymphatic

system. system. Cats are a critical part of the life cycle. Cats are a critical part of the life cycle. It is usually acquired by eating It is usually acquired by eating

undercooked meats but can also be undercooked meats but can also be acquired by contact with cat feces.acquired by contact with cat feces.

Primary problem is a congenital infection Primary problem is a congenital infection of fetus, resulting in either a stillbirth or a of fetus, resulting in either a stillbirth or a child with severe brain damage or vision child with severe brain damage or vision problems. problems.

ToxoplasmosisToxoplasmosis

The normal final The normal final host is cat and host is cat and relatives in the relatives in the family Felidae, only family Felidae, only hosts in which the hosts in which the Oocyst – producing Oocyst – producing sexual stage of sexual stage of Toxoplasma can Toxoplasma can developdevelop

By feeding on Mice brains Cats By feeding on Mice brains Cats can get Infectedcan get Infected

Events on Rat to CatEvents on Rat to CatTransmissionTransmission

Spread from Rats – Cats to Spread from Rats – Cats to HumansHumans

Spread of ToxoplasmosisSpread of Toxoplasmosis

Development in CatDevelopment in Cat Organisms ( either Organisms ( either

sporozoites from sporozoites from Oocysts or Bradyzoites Oocysts or Bradyzoites from tisse cysts ) from tisse cysts ) invade the muscle invade the muscle cells of cats samll cells of cats samll intestine where they intestine where they from Schizonts or from Schizonts or Gametocytes after Gametocytes after sexual fusion of sexual fusion of Gametes,oocysts Gametes,oocysts develop exit from the develop exit from the host cells into the gut host cells into the gut lumen of the cat and lumen of the cat and pass out via fecespass out via feces

Structure of SporozoitesStructure of Sporozoites

In each Oocysts two In each Oocysts two sporocysts form and sporocysts form and in about 48 hours in about 48 hours four sporozoites four sporozoites form within form within sporocyst.sporocyst.

The Oocyst with its The Oocyst with its each Sporozoites each Sporozoites when ingested can when ingested can either repeat its either repeat its sexual cycle in a Catsexual cycle in a Cat

Events on Development in Events on Development in manman

When man ingests When man ingests Oocysts with eight Oocysts with eight Sporozoites excreted in Sporozoites excreted in Cats feces, can Cats feces, can establish an infection establish an infection and reproduces and reproduces AsexuallyAsexually

In humans Oocysts open In humans Oocysts open in duodenum and in duodenum and releases eight releases eight Sporozoites which pass Sporozoites which pass through the gut wallthrough the gut wall

Circulate in body and Circulate in body and invade various cellsinvade various cells

Cycles of Development in Cycles of Development in ManMan

Invasion of Lymphnodes lead to Invasion of Lymphnodes lead to chronic infectionschronic infections

Sporozoites invade Sporozoites invade various cells especially various cells especially macrophages where macrophages where they from Trophozoites they from Trophozoites further multiply break further multiply break out and spread the out and spread the infection to infection to lymphnodes and other lymphnodes and other organsorgans

The rapidly multiplying The rapidly multiplying Crescentric cell Crescentric cell (Tachyzoites ) initiate (Tachyzoites ) initiate the acute stage of the acute stage of diseasedisease

Invade OrgansInvade OrgansBrain involvement carries higher Brain involvement carries higher

Morbidity and MortalityMorbidity and Mortality In futher development In futher development

they penetrate new they penetrate new cells especially Eye cells especially Eye and Brain.and Brain.

Further development Further development slows down in these slows down in these organs called ad organs called ad Bradyzoites to form a Bradyzoites to form a quiescent tissue cysts quiescent tissue cysts

The event lead to The event lead to chronic stage of chronic stage of diseasedisease

Fate of Tissue CystsFate of Tissue CystsShowing multiple tissue cystsShowing multiple tissue cysts

The tissue cysts The tissue cysts are infective when are infective when ingested by cats or ingested by cats or eaten by other eaten by other animals, where animals, where tissue cysts are tissue cysts are formedformed

In man it dead end In man it dead end of disease of disease

Implications on Human Implications on Human HealthHealth

In Humans In Humans producesproduces

1 Congenital 1 Congenital ToxoplasmosisToxoplasmosis

2 Post natal 2 Post natal ToxoplasmosisToxoplasmosis

Many Humans at risk withMany Humans at risk withToxoplasmosisToxoplasmosis

Congenital ToxoplasmosisCongenital Toxoplasmosis

Congenital infection Congenital infection develop in fetus develop in fetus only when non only when non immune mothers immune mothers are infected during are infected during pregnancypregnancy

Post natal Post natal Toxoplasmosis is Toxoplasmosis is less severe.less severe.

Other Human InfectionsOther Human InfectionsEarly detection reduce MorbidityEarly detection reduce Morbidity

Toxoplasmosis Toxoplasmosis produces severe produces severe Human infections Human infections in patient with in patient with

AIDSAIDS

The chronic The chronic infection is altered infection is altered

to Acute to Acute manifestationsmanifestations

Toxoplasmosis - Toxoplasmosis - ImmunosupressedImmunosupressed

Varying degrees of Varying degrees of disease may occur disease may occur in in Immunosupressed Immunosupressed indivudals results in indivudals results in

RetinitisRetinitis ChorioretinitsChorioretinits PneumoniasPneumonias Other non specific Other non specific

manifestionsmanifestions

Toxoplasmosis - RetinitisToxoplasmosis - Retinitis

Morphology and Identification Morphology and Identification ofof

ToxoplasmosisToxoplasmosis The Trophozoites are The Trophozoites are

boat shapedboat shaped Thin walled cell Thin walled cell Size is 4–7 x2-4 microns Size is 4–7 x2-4 microns

lie within tissue cellslie within tissue cells But appear larger when But appear larger when

outside the tissue celloutside the tissue cell Stain lightly with Stain lightly with

Giemsa’s stainGiemsa’s stain True cysts contain True cysts contain

many thousands of many thousands of spore like Bradyzoitesspore like Bradyzoites

Culturing ToxoplasmaCulturing Toxoplasma

Toxoplasma gondii Toxoplasma gondii may be cultured in may be cultured in the presence of the presence of living cells in the living cells in the culture tissues or culture tissues or eggseggs

Organisms can be Organisms can be seen intracellularly seen intracellularly or extracellularlyor extracellularly

PathogenesisPathogenesis The Tacyzoites have predilection for parenchymal The Tacyzoites have predilection for parenchymal

cells and Reticulo endothelial system and directly cells and Reticulo endothelial system and directly destroys the cells.destroys the cells.

Humans are relatively resistant to infectionHumans are relatively resistant to infection But low grade infection of lymph node persistsBut low grade infection of lymph node persists When tissue cysts ruptures – releases number of When tissue cysts ruptures – releases number of

Bradyzoites Bradyzoites Local hypersensitivity reaction may cause Local hypersensitivity reaction may cause

inflammation.inflammation. Causes blocking of blood vesselsCauses blocking of blood vessels Causes death of cells near damaged areaCauses death of cells near damaged area

Congenital InfectionCongenital Infection

Lead toLead to Still BirthStill Birth

ChorioretinitsChorioretinitsIntracellular calcificationIntracellular calcification

Psychomotor Psychomotor disturbancesdisturbances

HydrocephalyHydrocephalyMicrocephalyMicrocephaly

Prenatal toxoplasmosis Prenatal toxoplasmosis may manifest with may manifest with

blindness apart from blindness apart from congenital defectscongenital defects

Toxoplasmosis in PregnancyToxoplasmosis in Pregnancy

In 1 st TrimesterIn 1 st TrimesterMay lead to still birthMay lead to still birth

Major central Major central nervous system nervous system

anomaliesanomalies In 2In 2ndnd Trimester Trimester

Less severe Less severe complicationscomplications

Birth Anomalies still Birth Anomalies still commoncommon

Babies infected with congenital Babies infected with congenital Toxoplasmosis manifest withToxoplasmosis manifest with

brain damage brain damage enlarged spleen and liver enlarged spleen and liver eye damage eye damage jaundice jaundice poor motor coordination poor motor coordination unusually small head unusually small head rash rash

Late Anomalies in Late Anomalies in ToxoplasmosisToxoplasmosis

Clinical manifestation in infected fetus Clinical manifestation in infected fetus may be delayed until long after birthmay be delayed until long after birth

Even may present during early childhood.Even may present during early childhood. Neurological problems of learning Neurological problems of learning

difficulties may be caused by long delayed difficulties may be caused by long delayed effects of late prenatal infection.effects of late prenatal infection.

Diagnosis of ToxoplasmosisDiagnosis of Toxoplasmosis Desired specimens,Desired specimens, Blood ( Buffy coat of Blood ( Buffy coat of

heparinised sample )heparinised sample ) SputumSputum CSFCSF ExudatesExudates LymphnodesLymphnodes Tonsil tissuesTonsil tissues Striated muscle biopsyStriated muscle biopsy Ventricular fluid in Ventricular fluid in

NeonatesNeonates

Microscopic Examination of Microscopic Examination of TissuesTissues

Smears and sections Smears and sections stained with Giemsa’s stained with Giemsa’s stainstain

Periodic acid Schiff Periodic acid Schiff method preferredmethod preferred

The densely packed The densely packed cysts seen in the brain cysts seen in the brain or other parts of or other parts of nervous system nervous system suggest chronic suggest chronic infectioninfection

SerologySerology

Sabin Feldman dyeSabin Feldman dyetesttest

based on principle that based on principle that Antibodies to Antibodies to Toxoplasma appear in 2-Toxoplasma appear in 2-3 weeks that will render 3 weeks that will render the membrane of the the membrane of the laboratory cultured living laboratory cultured living T.gondii impermeable to T.gondii impermeable to Alkaline methylene Alkaline methylene blue blue ,So the organism ,So the organism are unstained in the are unstained in the presence of serum presence of serum with antibodieswith antibodies

Newer Methods in DiagnosisNewer Methods in Diagnosis

Immuno florescent Immuno florescent assay method.assay method.

ELISA for IgM and IgG ELISA for IgM and IgG detectiondetection

PCRPCR Frankel’s Frankel’s

intracutaneous test intracutaneous test useful for useful for epidemiologcal epidemiologcal purpose purpose

ImmunityImmunity

Acquired immunity in Acquired immunity in women is particularly women is particularly protective to the fetus.protective to the fetus.

In Immunosupressed In Immunosupressed and AIDS patients and AIDS patients changes the host changes the host resitance and causes resitance and causes chronic infection chronic infection becomes fulminating becomes fulminating acute Toxoplasmosisacute Toxoplasmosis

TreatmentTreatment

Combination of Pyramethamine and Combination of Pyramethamine and Sulphadiazine or TrisulfapyramidinesSulphadiazine or Trisulfapyramidines

Other alternative DrugsOther alternative Drugs

SpiramycinSpiramycin

ClindamycinClindamycin

Trimethoprim – SulphmethoxazoleTrimethoprim – Sulphmethoxazole

In pregnancy – Spriamycin is In pregnancy – Spriamycin is recommended drugrecommended drug

Control of ToxoplasmosisControl of Toxoplasmosis

Avoidance of human Avoidance of human contact with Cat feces contact with Cat feces is highly important is highly important measure.measure.

Changing of Cat litter Changing of Cat litter and safe disposal can and safe disposal can prevent transmisionprevent transmision

Pregnant women Pregnant women should avoid should avoid contact with kittenscontact with kittens

Screening of pregnant womenScreening of pregnant women

Periodic screening Periodic screening of pregnant women of pregnant women with high risk for with high risk for IgG and IgM IgG and IgM antibodies to antibodies to Toxoplasmosis is Toxoplasmosis is recommendedrecommended

Care of the MeatCare of the Meat

Avoid eating raw or Avoid eating raw or undercooked meat.undercooked meat.

Freezing < -20Freezing < -2000cc Heating at 50Heating at 5000c for c for

4-6 minutes 4-6 minutes destroys the cysts destroys the cysts and sterilizes the and sterilizes the meat.meat.

Created for Health Created for Health Awareness on Awareness on ToxoplasmosisToxoplasmosis

Dr.T.V.Rao MDDr.T.V.Rao MD

EmailEmail

doctortvrao@gmail.comdoctortvrao@gmail.com