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Toxoplasmosis

10/1/2008 - Michael L. Socol, MD

Editor: Pamela D. Berens, MD

REVISED PEARL - July 2016

Toxoplasma gondii is a protozoan which can lead to human infection through infected uncooked meat, exposure to contaminated soil or water, eating soil contaminated fruits or vegetables, or exposure to infected cat feces.  Most infections are asymptomatic, but immunocompromised hosts (e.g. HIV infected individuals) can manifest such problems as central nervous system infection, myocarditis, or pneumonitis. The diagnosis is made by serology showing seroconversion from negative to positive IgM or IgG antibodies.  Conversion requires confirmation in a reference laboratory.  Maternal IgG avidity testing may also be useful to assist with timing the primary infection for patient counseling.

Congenital infection is most likely to occur following maternal infection in the third trimester, although first trimester fetal infection is most severe.  Most infected fetuses are asymptomatic at birth.  Characteristic ultrasound findings include hyperechoic intracranial calcifications and ventriculomegaly, which carry a poor prognosis.  The diagnosis of congenital infection can be confirmed by PCR of amniotic fluid.  Uncertainty surrounding treatment efficacy persists, although treatment is generally recommended.  Treatment may include pyrimethamine, sulfadiazine and folinic acid in addition to using spiramycin to reduce transplacental transfer of the parasite.  Efforts in the United States are primarily directed toward prevention of infection rather than routine screening.  Careful hand washing, washing of fruits and vegetables, and avoidance of cat litter or uncooked meat are all advised.

Further Reading:

Duff P. Maternal and fetal infections. In: Maternal-Fetal Medicine: Principles and Practice. Editors: Creasy RK, Resnik R, Iams JD et al. 7th Edition, Saunders, 2013.

Cytomegalovirus, Parvovirus B19, Varicella zoster and Toxoplasmosis in Pregnancy. ACOG Practice bulletin # 151, June 2015

Initial approval 10/2008; Major revision 1/2015; Revised 7/2016.

 

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