Estratificacion de una ciudad hiperendemica en dengue hemorragico / Stratification of a city with hyperendemic dengue hemorrhagic fever

RESUMEN

La gran heterogeneidad ambiental de viviendas y barrios en los centros urbanos donde se cria Aedes aegypti, principal vector del dengue, junto con la escasez de recursos y de personal entrenado en el control de mosquitos constituyen retos para cualquier iniciativa destinada a controlar el dengue hemorragico (DH). Una adecuada vigilancia epidemiologica puede servir de base para comenzar a estratificar los centros urbanos e identificar las zonas criticas donde deben concentrarse las tareas de control. En este estudio, se estratifico una ciudad hiperendemica en dengue hemorragico (Maracay, Venezuela) con la ayuda de un sistema de informacion geografica (SIG) y el analisis de la persistencia, la incidencia y la prevalencia del dengue mediante diagnosticos clinicos registrados de 1993 a 1998. Maracay tiene cerca de un millon de habitantes que viven en unos 349 barrios de 6 poblaciones que integran el Area Metropolitana, donde se notificaron 10.576 casos de dengue, 2.593 casos de DH y 8 defunciones. La incidencia de DH mostro una relacion directa con la incidencia del dengue, el numero de habitantes y la densidad poblacional. El patron espacial de la incidencia del dengue fue estable durante los anos estudiados y se encontraron relaciones positivas y significativas de la incidencia del dengue por barrio entre pares de anos. La persistencia del dengue se relaciono directamente con la incidencia mensual por barrio. Estos patrones espaciales facilitaron la estratificacion de la ciudad en tres estratos 68 barrios sin dengue aparente, 226 barrios con baja persistencia y prevalencia, y 55 barrios con alta persistencia y prevalencia. Se recomienda otorgar alta prioridad de control a estos 55 barrios que ocupan 35 por ciento del area urbana y presentaron 70 por ciento de todos los casos de dengue

ABSTRACT

Any effort to control dengue hemorrhagic fever (DHF) faces a number of challenges. Among these are the great environmental heterogeneity of homes and neighborhoods in urban centers where the primary dengue vector, Aedes aegypti, breeds, as well as shortages of resources and of personnel trained in mosquito control. Adequate epidemiological surveillance could serve as a basis to begin to stratify urban communities and identify the areas in them where control efforts should be focused. In this study we stratified Maracay, Venezuela, a city with hyperendemic dengue hemorrhagic fever, using a geographic information system and analyzing the persistence, incidence, and prevalence of dengue, by means of clinical diagnoses reported from 1993 through 1998.Maracay has around one million inhabitants living in some 349 neighborhoods in the six communities that make up the greater Maracay metropolitan area. During that 1993­1998 period the Maracay area reported 10 576 cases of dengue, 2 593 cases of DHF, and 8 deaths. The incidence of DHF was related to the incidence of dengue, the number of inhabitants in an area, and population density. The spatial pattern of dengue incidence was stable over the years that were studied, and significant, positive relationships were found between pairs of years and the incidence of dengue by neighborhood. The persistence of dengue was related directly to monthly incidence by neighborhood. These spatial patterns helped to divide the city into three strata 68 neighborhoods without apparent dengue, 226 neighborhoods with low persistence and prevalence, and 55 neighborhoods with high persistence and prevalence. We recommend giving the highest priority for control efforts to these 55 neighborhoods, which make up just 35% of the Maracay urban area but had 70% of all the reported dengue cases