Toxoplasma Gondii26

Justin L. DeNiseMicrobiology 410:615:01

4/5/2007

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Kingdom - ProtistaPhylum - ApicomplexaClass - ConoidasidaSubclass - CoccidiasinaOrder - EucoccidioridaFamily - SarcocystidaeGenus - ToxoplasmaSpecies - T. gondii

T. gondii - DeNise

• Obligate Intracellular Parasite

• Toxoplasmosis

• Usually Harmless

• Oral-Fecal Pathway -Cats

• 400-4000 cases annually in the US

General Information Classification

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Life Cycle

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T. gondii - DeNise

Toxoplasmosis

• Primarily Infects Blood and Lymph• Flu-like Symptoms• Prevalence- 22-40% (60 million+ in the US alone)• Can cause brain damage in immunocompromised individuals -AIDS/Chemotherapy -Brain Defects -Vision Impairment if it develops in the eye -Fetuses -Stillbirth -Brain Defect• Side effect: schizophrenia, neuroticism, paranoia• Antibody concentration can increase proportion of births to lean towards males

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Prevalence

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T. gondii - DeNise

How to Become Infected• Accidental ingestion of fecal matter from an infected cat 7-21 days post infection

• Ingestion of contaminated raw or undercooked meat -Pork, lamb, venison -Cross-contamination with infected meat

• Drinking water infected with T. gondii

• Receiving an infected organ or infected blood in a transfusion (rare)

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T. gondii - DeNise

Development of Toxoplasmosis

• Ingestion of oocysts• -8 sporozoites• Trophozoites (tachyzoites) -‘Tachy’ means ‘fast’ in Greek -Named due to their rapid reproduction• Increase in immune response causes the host cell to develop cell walls to form “tissue cysts”• Bradyzoites - ‘Brady’ means ‘slow’ in Greek -Named for slow reproduction rate inside cysts -Can reproduce silently for years• Activation of a cyst

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T. gondii - DeNise

Symptoms

Typical Cases• Flu-like symptoms (swollen lymph glands, muscle aches, and malaise)

Severe Cases (acute infection or reactivation)• Ocular and neural damage Reduced Vision Blurred Vision Pain (bright light) Redness of the Eye Tearing

Infected Infants• Few have symptoms at birth, may reappear up to three decades later• Hydrocephaly/Microcephaly, Intracranial Calcifications, Deafness, Seizures, Cerebral Palsy, Retinal Damage, and Mental Retardation

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T. gondii - DeNise

Treatment• Not necessary if the individual is otherwise healthy and not pregnant• Pyrimethamine with sulfadiazine and folinic acid -Can be toxic to patient -Useless once in bradyzoite stage

Detection• Serological tests (not very accurate)• PCR -Relatively new -Accuracy approaches 100%

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T. gondii - DeNise

Pyrimethamine

• Interferes with folic acid synthesis, which is necessary for DNA and RNA synthesis in most protozoan• Inhibits dihydrofolate reductase• Anti-malarial

Sulfadazine

• Interferes with folic acid synthesis• Inhibits dihydropteroate synthetase• Synnergistic with pyrimethamine

Folinic Acid

• Can be converted to folic acid without dihydrofolate reductase• Reduces side effects of the other medications

Side Effects

• Hyper sensitivity• Megaloblastic anemia -B12/folic acid deficiency-induced anemia• Leukopenia -Low WBC count• Thrombocytopenia -Low platelet count• Pancytopenia -Lower RBC, WBC, and platelet count• Atrophic glossitis• Hematuria -Blood in the urine• Cardiac arrhythmias• Pulmonary eosinophilia• Hyperphenylalaninemia -Phenylalanine Hydroxylase deficiency

(metal retardation)

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Antibody Detection

T. gondii - DeNise

Prevention

• Wear gloves when doing work outside that could involve soil• When preparing raw meat, always wash all utensils and the preparation area thoroughly with soap and hot water afterwards• Cook all meat to an internal temperature of 160° F (colorless fluids and no longer pink)• Never taste meat before it’s finished cooking• Clean kitty litter boxes daily• Do not feed undercooked meat to a cat• Keep your cat indoors and feed it dry or canned food• If you are immunocompromised or pregnant, have someone else empty the kitty litter box and generally take care of the cat• Always wash your hands with soap and hot water after being in a position that could possibly contaminate you

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T. gondii - DeNise

Questions to Think About

1.Why is Antibody Detection not very effective for T. gondii?

2. Why is it important to wash the kitchen utensils and preparation area thoroughly after preparing meat which could potentially contain T. gondii?

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Thanks

For Listening

T. gondii - DeNise

References• DPDx Diagnostic Findings Website:http://www.dpd.cdc.gov/DPDx/HTML/Toxoplasmosis.asp?body=Frames/S-Z/Toxoplasmosis/body_Toxoplasmosis_serol1.htm•Jaroslav Flegr. Women infected with parasite Toxoplasma have more sons, Naturwissenschaften, August 2006•Jeffrey L. Jones,* Deanna Kruszon-Moran,† and Marianna Wilson**Centers for Disease Control and Prevention, Atlanta, Georgia, USA; and †Centers for Disease Control and Prevention, Hyattsville, Maryland, USAVol. 13, No. 4 • April 2007• Jones JL, Kruszon-Moran D, Wilson M. Toxoplasma gondii infection in the United States, 1999–2000. Emerg Infect Dis [serial online] 2003 Nov [7/3/2007]. Available from: URL: http://www.cdc.gov/ncidod/EID/vol9no11/03-0098.htm•Torrey EF, Yolken RH. Toxoplasma gondii and schizophrenia. Emerg Infect Dis [serial online] Nov 2003 [7/3/2007]. Available from: URL: http://www.cdc.gov/ncidod/EID/vol9no11/03-0143.htm• CDC website: http://www.cdc.gov/ncidod/dpd/parasites/toxoplasmosis• Images from wikipedia.com 16