Clinical Research Directory

Inclusion Criteria: * Mother willing to sign informed consent form. * Healthy infant * No obvious congenital abnormalities or birth defects. * Stable household with no plans to leave the area for the next one year. Exclusion Criteria: * Parents are not willing to have child's blood drawn. * Parents are planning to enroll child into another interventional clinical study during the time period of this trial that could affect the outcomes of this study. * Mother not willing to have blood drawn and breast milk extracted. * Parents not willing to have field research assistant in home two times per week. * History of seizures or other apparent neurologic disorders. * Infant has any sibling currently or previously enrolled in this study, including a twin.