Neurocysticercosis in California: Clinical Characteristics and Associated Comorbidities Across the University of California Health System

Introduction

Neurocysticercosis (NCC) is an infection of the central nervous system caused by the tapeworm Taenia solium. Despite documented increases of NCC in California, large-scale studies characterizing affected populations remain limited. The spectrum of NCC associated neuropsychiatric comorbidities has not been well defined in U.S. populations. This study aimed to estimate the prevalence of NCC within the University of California (UC) Health System, characterize the population demographic and clinical features, and identify factors associated with epilepsy among individuals with NCC.

Methodology/Principal Findings

We conducted a cross-sectional analysis of electronic health records from 2012 through March 2026 using the UC Health Data Warehouse, which integrates data from six UC Health systems. Among individuals aged ≥ 1 year, there were 713 individuals with a diagnosis of NCC corresponding to a prevalence of 6.17 per 100,000. A comparison group was randomly selected at a 1:10 ratio. Relative to the comparison group, NCC patients were significantly older, more likely to identify as Hispanic or Latino, more likely to speak Spanish as a primary language, and more likely to have Medicaid insurance. NCC was strongly associated with epilepsy (OR = 19.20, 95% CI: 15.74–23.46), as well as migraines, cognitive impairment, mood disorders, Parkinsons disease, substance use, stroke, and sleep disorders. After adjusting for age, gender, and ethnicity, male NCC patients had 26% higher odds of epilepsy compared to female patients.

Conclusion/Significance

In addition to epilepsy, NCC was associated with a broad range of neuropsychiatric comorbidities and occurred disproportionately among patients more likely to face socioeconomic and structural barriers to care, including limited insurance coverage, language barriers, and immigration-related challenges. These findings highlight the importance of recognizing NCC in non-endemic settings, where this often underrecognized disease contributes substantially to neurologic morbidity in a vulnerable population.

Author Summary

Neurocysticercosis is an infection of the brain caused by the larvae of the tapeworm Taenia solium. It is commonly found in regions of Latin America, Africa, and Asia. It is among the leading causes of acquired epilepsy worldwide. Although it is thought to be relatively rare in the United States, we suspected that it may be more common than currently recognized, particularly in states with large immigrant populations.

We reviewed 14 years of medical records from over 11 million patients across 6 hospitals within the University of California Health System to find all individuals diagnosed with neurocysticercosis and compared them with a similar group of patients without it. We found about 6 cases of neurocysticercosis per 100,000 patients. These patients were more likely to have illnesses such as epilepsy, migraines, cognitive impairment, Parkinson’s disease, mood disorders, and strokes compared to individuals without neurocysticercosis. They were also more likely to be Spanish-speaking, Hispanic or Latino, and insured through Medicaid.

Our findings suggest that NCC remains an underrecognized cause of neurological illness in California and highlight disparities associated with the disease, underscoring the need for further investigation of these relationships as well as equity-focused strategies to improve NCC diagnosis and care.