Changing pattern of neurocysticercosis in an urban endemic center (Guayaquil, Ecuador)

Objective: To confirm recent evidence suggesting a change in the pattern of disease expression of neurocysticercosis, manifested by a decreasing number of severe and recent infections. Methods: Retrospective cohort of 246 neurocysticercosis patients residing in Guayaquil, evaluated over 20 years (1990 to 2009). Eighty-seven patients were seen from 1990 to 1994, 58 from 1995 to 1999, 57 from 2000 to 2004, and 44 from 2005 to 2009. Neurocysticercosis was classified as active or inactive according to neuroimaging findings. Patients with parenchymal, subarachnoid or ventricular cystic lesions were considered to have active disease, and those with calcifications and chronic arachnoiditis were classified as inactive. Results: Mean age was 36.6 +/- 20 years, and 61% were women. The relative prevalence of active and inactive cases varied according to the year of evaluation. Active neurocysticercosis was found in 63% of patients seen between 1990 and 1994, in 48% between 1995 and 1999, in 47% between 2000 and 2004, and in only 18% between 2005 and 2009 (p<0.0001). Together with reduction of active cases, there was an increased prevalence of asymptomatic infections over the years (from 17.2% between 1990 and 1994 to 54.5% between 2005 and 2009; p<0.0001). Conclusion: In this single-center cohort, the relative prevalence of active cases of neurocysticercosis reduced over the past years, suggesting a decreased incidence of new infections. Improved sanitation together with widespread use of cysticidal drugs were the most likely causes of these findings. (c) 2011 Elsevier B.V. All rights reserved.