Three decades of neurocysticercosis mandatory notification in a Brazilian endemic region: clinical evolution and severity patterns.

Abstract

Background: Neurocysticercosis (NCC) is the leading cause of late-onset epilepsy in endemic regions, yet long-term data on severe forms remain limited. This study analyzed temporal trends in severe NCC over three decades following mandatory notification in a high-incidence region of Brazil.

Methods: This retrospective population-based study included Neurocysticercosis cases reported from January 1995 to September 2024 in a high-incidence endemic area of São Paulo State, Brazil. Confirmed NCC cases were reclassified as intracranial hypertension syndrome (IHS) or other clinical presentations (epileptic, meningeal, asymptomatic). Clinical, neuroimaging, and cerebrospinal fluid data were analyzed. Multivariable logistic regression identified factors associated with severe disease.

Results: Of 518 reported cases, 465 confirmed NCC cases were included. In the first decade (1991-2000, n = 262), 13.4% (35/262) were severe. Between these periods (2001-2010, n = 125), a steady decline in total incidence was observed. In the most recent period (2011-2020, n = 78), the proportion of severe cases rose to 65.4% (51/78). Meningeal manifestations were associated with increased severity risk (OR = 2.99; 95%CI: 1.81-4.94), whereas epileptic (OR = 0.30; 95%CI: 0.18-0.48) and asymptomatic presentations (OR = 0.21; 95%CI: 0.11-0.40) were protective. Neurosurgical procedures were required in 79.4% of severe cases.

Conclusions: Despite declining overall incidence, the increasing proportion of severe NCC (intracranial hypertension) likely reflects late-stage diagnoses of long-standing infections that remained asymptomatic for decades. This trend suggests a 'catch-up' effect in detecting complex cases through improved neuroimaging, even as primary prevention programs successfully reduce new infections. .