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A. Organism: Toxoplasma gondii, an intracellular parasite
B. Epidemiology
1. Cats are the primary hosts for T. gondii toxoplasmosis
2. Modes of transmission
a. Contact with oocysts from the feces of an infected cat. These oocysts can be transported by insects, herpes, group B streptococcus, varicella, chicken pox
b. Consumption of cysts in
(1) Undercooked meat (a) Lamb (b) Pork
(2) Unpasteurized milk
c. Blood products, as well as organ transplants
3. In the United States, roughly 30% of women of childbearing age have serologic evidence of prior infection
a. This rate is much higher in some European countries
b. Approximately two per 1,000 pregnant women in the United States will seroconvert during their pregnancy
C. Clinical manifestations
1. Approximately 805 of patients who become infected with T. gondii are asymptomatic, in which case the diagnosis relies entirely on serologic evaluation
2. Approximately 20 % of patients will have an acute mononucleosis-like Chlamydia, clamidia
syndrome which may last up to 3-4 months
D. The diagnosis in the adult generally relies on group B streptococcus, varicella, chicken pox serologic evaluation
1. Following acute toxoplasma, IgM is typically present.
week, but remains positive for several months, which may make an accurate
estimation of the time of infection difficult
2. IgG will appear within 1-2 weeks. Titers generally rise to greater than one
per 1,000 with acute infections
3. A strongly positive IgG titer in and of itself does not indicate a recent
infection. Any positive IgG liter should be accompanied by an IgM titer
Table 1
Outcome by Trimester of Acquisition
Trimester Infants Infected Clinically