Unrecognized ingestion of Toxoplasma gondii oocysts leads to congenital toxoplasmosis and causes epidemics in North America.
BACKGROUND
Congenital toxoplasmosis presents as severe, life-altering disease in North America. If mothers of infants with congenital toxoplasmosis could be identified by risks, it would provide strong support for educating pregnant women about risks, to eliminate this disease. Conversely, if not all risks are identifiable, undetectable risks are suggested. A new test detecting antibodies to sporozoites demonstrated that oocysts were the predominant source of Toxoplasma gondii infection in 4 North American epidemics and in mothers of children in the National Collaborative Chicago-based Congenital Toxoplasmosis Study (NCCCTS). This novel test offered the opportunity to determine whether risk factors or demographic characteristics could identify mothers infected with oocysts.


METHODS
Acutely infected mothers and their congenitally infected infants were evaluated, including in-person interviews concerning risks and evaluation of perinatal maternal serum samples.


RESULTS
Fifty-nine (78%) of 76 mothers of congenitally infected infants in NCCCTS had primary infection with oocysts. Only 49% of these mothers identified significant risk factors for sporozoite acquisition. Socioeconomic status, hometown size, maternal clinical presentations, and ethnicity were not reliable predictors.


CONCLUSIONS
Undetected contamination of food and water by oocysts frequently causes human infections in North America. Risks are often unrecognized by those infected. Demographic characteristics did not identify oocyst infections. Thus, although education programs describing hygienic measures may be beneficial, they will not suffice to prevent the suffering and economic consequences associated with congenital toxoplasmosis. Only a vaccine or implementation of systematic serologic testing of pregnant women and newborns, followed by treatment, will prevent most congenital toxoplasmosis in North America.
Department of Pediatrics, Rush University Medical Center, Chicago, Illinois, USA.
Kenneth
K
Boyer
Dolores
D
Hill
Ernest
E
Mui
Kristen
K
Wroblewski
Theodore
T
Karrison
J P
JP
Dubey
Mari
M
Sautter
A Gwendolyn
AG
Noble
Shawn
S
Withers
Charles
C
Swisher
Peter
P
Heydemann
Tiffany
T
Hosten
Jane
J
Babiarz
Daniel
D
Lee
Paul
P
Meier
Rima
R
McLeod
D000328:Adult; D000913:Antibodies, Protozoan / Q000097:blood; D019411:Clinical Laboratory Techniques / Q000379:methods; D004435:Eating; D005260:Female; D005506:Food Contamination / Q000706:statistics & numerical data*; D006801:Humans; D007118:Immunoassay / Q000379:methods; D007231:Infant, Newborn; D009656:North America / Q000453:epidemiology; D033661:Oocysts; D011247:Pregnancy; D014122:Toxoplasma / Q000276:immunology / Q000302:isolation & purification*; D014125:Toxoplasmosis, Congenital / Q000453:epidemiology*
D000913:Antibodies, Protozoan