...some of the central nervous system features of toxocariasis have been implicated as a cause of occult seizures, mental retardation, and developmental delays 3,4,15. Because pica is a risk factor for both toxocariasis and lead ingestion 16, it is possible that an element of the cognitive and mental deficits ascribed to toxocariasis may partially result from plumbism. ...the larvae may remain alive within the host for months, and host antibody levels may remain strongly positive for 2 or 3 years or more 17,31. ...in the CDC EIA, the presence of antibody titers greater than 1:32 may be considered reflective of active infection, although we are not aware of careful studies that have determined the length of persistent toxocaral antibodies over long periods of time.