potentially large number of patients with febrile seizures. The treating physician recorded demographic and clinical data including age, sex, race, immigrant status, foreign travel, prior seizure history, seizure type, CT and MRI findings, presump- tive diagnosis, and disposition. When blood was drawn from a patient as part of the evalu- ation, an additional tube was obtained for this study. Serum specimens from 890 of the 1,801 patients enrolled were sent to the Centers for Disease Control and Prevention so that sero- logic testing for cysticercosis could be performed. Serum sam- ples were tested by enzyme-linked immunoelectrotransfer blot for Taenia solium–specific antibodies, as described (15,16). Briefly, this assay uses seven purified glycoprotein antigens from larval cysts of T. solium, namely, GP50, GP42-39, GP24, GP21, GP18, GP14, and GP13, where the prefix GP stands for glycoprotein and the number indicates the molecular mass in kilodaltons. These antigens are used in an immunoblot format to detect infection-specific antibodies. Reactions to at least one antigen band are considered positive (15,16). On the basis of a classification scheme proposed by Del Brutto (17), our case definition for neurocysticercosis required either 1) CT scan finding(s) characteristic of neurocysticerco- sis (i.e., multiple calcifications or multiple cystic lesions) with or without a positive serologic test, or 2) CT scan finding(s) consistent with neurocysticercosis (i.e., a single cystic, calci- fied, or hypodense lesion) and a positive serologic test. Radiol- ogists at each site read CT scans without regard for or knowledge of the study. Study coordinators at each site then abstracted the absence or presence of findings relevant to the study from the radiology reports. Simple descriptive statistics were used to summarize the clinical features of patients with and without neurocysticercosis. Relative risk ratios (RRs) and their corresponding 95% confidence intervals (CIs) were determined by Fisher’s exact test. Results A total of 1,801 eligible patients with 1,833 emergency department visits were enrolled during the 2-year study period. Twenty-eight patients had multiple visits; four patients under- went evaluation on three separate occasions (Table 1). A diverse group of seizure patients were enrolled in the study (Table 2). From the entire study population, 2.1% (38) patients met the case definition for neurocysticercosis (Table 3). Of patients who underwent both CT scanning and serologic testing, 2.9% met the case definition. Thirty-four patients satisfied the case definition based on classic CT scan findings, and four satisfied the case definition based on a positive serologic test coupled with CT scan findings consistent with neurocysticercosis. Neurocysticercosis was identified at 9 of the 11 study sites; 6 sites enrolled more than one patient (Table 3). Patients with this disease tended to be younger than patients who did not meet the case definition (Table 4). Patients were also more likely to be Hispanic, have been born outside the United States, have visited or lived in an endemic region, be unin- RESEARCH Table 1. Demographic and clinical characteristics of 1,833 neuro- imaged emergency department seizure patientsa Characteristics Sex (male) Race/ethnicity Black White, non-Hispanic Hispanic Native American Asian/Pacific Islander Other or unknown Insurance Medicare/private Medicaid Uninsured Immigrant statusb Born in USA Not born in USA Unknown Exposure to disease-endemic region No travel outside USA Exposure to disease-endemic region Unknown travel history Seizure type Generalized tonic/clonic Focal motor Partial complex Unknown or undocumented Seizure history Prior seizure history No prior seizure history Unknown seizure history Patients (%) 1,220 (67) 753 (41) 643 (35) 320 (17) 43 (2.3) 33 (1.8) 41 (2.2) 462 (25.2) 391 (21.3) 762 (41.6) 820 (61) 178 (13) 350 (26) 950 (51.8) 342 (18.7) 541 (29.5) 1,577 (86) 114 (6.2) 86 (4.7) 56 (3.1) 810 (44) 896 (49) 127 (7) aThe median age (interquartile range) in yrs for these patients was 40 (range 30–51 yrs). b1,348 patients; immigrant status data was not collected on the first 485 patients. sured, and have a reported history of neurocysticercosis. Over- all, approximately 9% of patients with Hispanic ethnicity who came to an emergency room with a seizure met the case defini- tion for neurocysticercosis. The prevalence of the disease in the Hispanic patients with seizures ranged from 9% to 13.5% in the highest risk sites. Patients meeting the case definition for neurocysticercosis were not more likely to have a new-onset seizure (versus hav- ing an established history of seizures; RR 1.1; CI 0.56 to 2.01). Neurocysticercosis patients were, however, more likely to have focal motor or partial complex seizures than those with- out neurocysticercosis (RR 2.6; CI 1.3 to 5.5) (Table 4). Serologic testing was performed on 49.4% (890) of the 1,801 patients enrolled, and results were positive in 2% (18) Emerging Infectious Diseases • Vol. 8, No. 6, June 2002 609