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Infectious DiseasesViral Infections

Toxoplasmosis Clinical Signs Diagnosis and Treatment


          Caused by protozoan – Toxoplasma gondii
          The domestic cat is the definitive host with infections via:
          Ingestion of cysts (meats, garden products)
          Contact with oocysts in faeces
          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 infection in the 3rd trimester
Fetal death higher with infection in the 1st trimester

Clinical Manifestations

          Most (70-90%) are asymptomatic at birth
          The classic triad of symptoms:
          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 


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

Toxo Screening:

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

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