Toxoplasmosis:

          Caused by protozoan – Toxoplasma gondii
          Domestic cat is the definitive host with infections via:
          Ingestion of cysts (meats, garden products)
          Contact with oocysts in feces
          Much higher prevalence of infection in European countries (ie France, Greece)
          Acute infection usually asymptomatic
          1/3 risk of fetal infection with primary maternal infection in pregnancy
          Infection rate higher with infxn in 3rd trimester
Fetal death higher with infxn in 1st trimester

Clinical Manifestations

          Most (70-90%) are asymptomatic at birth
          Classic triad of symptoms:
          Chorioretinitis
          Hydrocephalus
          Intracranial calcifications
          Other symptoms include fever, rash, HSM, microcephaly, seizures, jaundice, thrombocytopenia, lymphadenopathy
          Initially asymptomatic infants are still at high risk of developing abnormalities, especially chorioretinitis 
chorioretinitis-in-toxoplasmosis
Chorioretinitis

Diagnosis:

          Maternal IgG testing indicates past infection (but when…?)
          Can be isolated in culture from placenta, umbilical cord, infant serum
          PCR testing on WBC, CSF, placenta
          Not standardized
          Newborn serologies with IgM/IgA

Toxo Secreening:

          Prenatal testing with varied sensitivity not useful for screening
          Neonatal screening with IgM testing implemented in some areas
          Identifies infected asymptomatic infants who may benefit from therapy

Prevention and Treatment:

          Treatment for pregnant mothers diagnosed with acute toxo
          Spiramycin daily
          Macrolide antibiotic
          Small studies have shown this reduces likelihood of congenital transmission (up to 50%)
          If infant diagnosed prenatally, treat mom
          Spiramycin, pyrimethamine (anti-malarial, dihydrofolate reductase inhib), and sulfadiazine (sulfa antibiotic)
          Leucovorin rescue with pyrimethamine
          Symptomatic infants
          Pyrimethamine (with leucovorin rescue) and sulfadiazine
          Treatment for 12 months total
          Asymptomatic infants
          Course of same medications
Improved neurologic and developmental outcomes demonstrated (compared to untreated pts or those treated for only one month

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