Toxoplasma gondiiBy Jason Soderberg and Sam Rawson

Toxoplasma gondii•An intestinal coccidium•Domain: Eukaryota •Kingdom: Chromalveolata •Superphylum: Alveolata Phylum:

Apicomplexa•Class: Conoidasida Subclass: Coccidiasina•Order: Eucoccidiorida •Family: Sarcocystidae •Genus: Toxoplasma •Species: T. gondii

Geographic Distribution

Found all over the world- Estimates suggest that over 30% of

human population is infected- With over 60 million people in the United

States infected.

HostsDefinitive Hosts Intermediate hosts

• Rats▫ Toxoplasma gondii can

change the hosts behavior making rats fearless in front of cats.

• Birds• Humans• Warm blooded mammals • Asexual reproduction

• http://www.youtube.com/watch?feature=player_detailpage&v=__K104jSGzs#t=62s

• Cats

• Sexual reproduction occurs

Indirect Life Cycle: Intermediate Host

1. Oocysts exit cat via feces on ingested food or water2. Oocysts enter macrophages in intestinal lining3. In the gut oocysts becomes tachyzoites which move

to other parts of the body via the bloodstream4. Once in tissues tachyzoites further develop into the

cyst bradyzoite in muscle and neural tissue▫ Commonly found in skeletal muscles, brain,

myocardium and eyes where they can remain for many decades

▫ If an intermediate host is eaten by a cat or human the tissue cysts get ingested and parasite activates in small intestines

Direct Life Cycle: Definitive Host• Tissue cysts (oocyst and sporocyst) are ingested

by a cat (feed on infected mouse)• Break open releasing sporozoites• Sporozoites enter intestinal epithelial cells of cat• Undergo schizogony to form schizont with

merozoites• Merozoites burst out (occurs 2 0r 3 times)• Micro and macrogametes form and fertilize

eachother to produce a zygote• Zygote ecysts to form oocyst which is excreted in

feces

Stages of Toxoplasma gondii

A. Tachyzoites : in lung smear

B. Tissue cysts in muscle

C. Tissue cyst seperated from host tissue

D. SchizontE. Male gamete : 2

flagellaF. Unsporulated oocyst

in feces G. Sporulated oocyst

with a thin oocyst wall

4 ways of infection:

1. Consuming undercooked infected meat.2. Ingesting contaminated water / soil3. Blood transfusions (SUPER RARE) 4. Congenital infection: Mother to child.

Toxoplasmosis

•Most people are asymptomatic and do not display symptoms ▫**immunosuppressed patients and pregnant

women must be cautious•Prenatally aquired T. gondii often infects

brain and retina▫Wide spectrum of clinical disease from

diminished vision to a classic tetrad of signs: retinochoroiditis, hydrocephalus, convulsions, and intracerebral calcifications

Symptoms▫Flu , Swollen lymph glands and muscle

aches lasting for a month or more▫Severe cases: cause damage to brain, eyes

or other organs.▫Encephalitis: acute inflammation of the

brain Important and severe manifestation of

toxoplasmosis in immunosuppressed patients Can cause coma and death

▫May contribute to schizophrenia

Diagnosis / TreatmentDiagnosis Treatment

• Serelogical test, for Immunoglobulin antibodies (IgG, IgA, IgM)

• Molecular techniques can be used to detect toxoplasma gondi DNA in amniotic fluid.

• Combinations of Pyrimethamine with trisulapyrimidines or sulfadiazine plus folinic acid

• Sulfamethoxazole and trimethoprime can be used if above is not available

Prevention• Cook food to safe temps • Freeze meat for several days

before cooking• Peel/ wash fruits and veggies • Wash cutting boards with hot

soapy water after contact with raw meat.

• Avoid untreated water • Change litter box daily and

wash hands after• Keep sandboxes covered. • If pregnant over immuno-

comprimised have someone else do it

• Keep cats indoors.

DISSSCUCCCCCCSION

1. Where is Toxoplasma gondii geographically located??

2. What is the definitive host? 3. Where does asexual reproduction occur?

SOURCES

• CDC: http://www.cdc.gov/parasites/toxoplasmosis/index.html

• Parasites in humans http://www.parasitesinhumans.org/toxoplasma-gondii.html

• ArS.usda.gov http://www.ars.usda.gov/main/docs.htm?docid=11013

• NCBI▫http://www.ncbi.nlm.nih.gov/books/

NBK7752/