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.
Hosts Definitive HostsIntermediate 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 water 2.Oocysts enter macrophages in intestinal lining 3.In the gut oocysts becomes tachyzoites which move to other parts of the body via the bloodstream 4.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.Schizont E.Male gamete : 2 flagella F.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 / soil 3.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 / Treatment DiagnosisTreatment 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?