Vigilancia de laboratorio de enfermedad meningocóccica invasora en Chile, 2006-2012

Background: Laboratory surveillance of Invasive Meningococcal Disease (IMD) is performed by the Institute of Public Health of Chile. It confrms identifcation, classifes in serogroups and analyzes the genetic profles of Neisseria meningitidis isolates from laboratories throughout the country. Aim: To show the results of this surveillance from 2006 to 2012. Methods: A descriptive data analysis of the confrmed cases of IMD and serological characterization, susceptibility and genetic profles of the isolates. The analysis was disaggregated by serogroup, age and region. Results: From 2006 to 2012, 486 isolates of N. meningitidis were confrmed. In 2011 a rise in IMD rates was observed due to an increase in W serogroup cases, mainly affecting children aged 5 years or less. Serogroup W became the most prevalent during 2012 (58.3%), replacing the historically prevalent serogroup B. Predominating strains belonged to ST-32 complex/ET-5 complex (40, 4% of strains) and ST-41/44 complex/ Lineage 3 (45, 9% of strains). Conclusions: Laboratory surveillance has allowed the early detection of increasing IMD caused by serogroup W, which is emergent in Chile. This information has reinforced the daily monitoring of new cases, in collaboration with all the clinical laboratories of the country.