Enabling countries to manage outbreaks: statistical, operational, and contextual analysis of the early warning and response system (EWARS-csd) for dengue outbreaks

Introduction

Dengue is currently the fastest-spreading mosquito-borne viral illness in the world, with over half of the world's population living in areas at risk of dengue. As dengue continues to spread and become more of a health burden, it is essential to have tools that can predict when and where outbreaks might occur to better prepare vector control operations and communities' responses. One such predictive tool, the Early Warning and Response System for climate-sensitive diseases (EWARS-csd), primarily uses climatic data to alert health systems of outbreaks weeks before they occur. EWARS-csd uses the robust Distribution Lag Non-linear Model in combination with the INLA Bayesian regression framework to predict outbreaks, utilizing historical data. This study seeks to validate the tool's performance in two states of Colombia, evaluating how well the tool performed in 11 municipalities of varying dengue endemicity levels.

Methods

The validation study used retrospective data with alarm indicators (mean temperature and rain sum) and an outbreak indicator (weekly hospitalizations) from 11 municipalities spanning two states in Colombia from 2015 to 2020. Calibrations of different variables were performed to find the optimal sensitivity and positive predictive value for each municipality.

Results

The study demonstrated that the tool produced overall reliable early outbreak alarms. The median of the most optimal calibration for each municipality was very high: sensitivity (97%), specificity (94%), positive predictive value (75%), and negative predictive value (99%; 95% CI).

Discussion

The tool worked well across all population sizes and all endemicity levels but had slightly poorer results in the highly endemic municipality at predicting non-outbreak weeks. Migration and/or socioeconomic status are factors that might impact predictive performance and should be further evaluated. Overall EWARS-csd performed very well, providing evidence that it should continue to be implemented in Colombia and other countries for outbreak prediction.

[Maintaining measles elimination status in Colombia during outbreak control, 2019Manutenção do status de eliminação do sarampo na Colômbia durante o controle de surtos, 2019]

Objective

Describe measles outbreaks caused by importation of multiple cases, and the corresponding control interventions.

Methods

Descriptive study of measles outbreaks caused by the importation of multiple cases to Colombia in 2018-2019. Case definitions, classification of source of infection, collection of biological specimens, searches for suspected cases, case identification, and contact tracing were employed. Vaccination records were obtained from vaccination cards or from the Colombian information system. Nationality was determined from records found in the public health surveillance system. The incident command system was used, and response teams and action plans were activated to control outbreaks.

Results

In March 2018, the first case of measles imported from Venezuela was confirmed. Measles incidence in 2018 was 0.2 cases per 100 000 population, and it was 0.3 per 100 000 in 2019. The case fatality rate in 2019 was 0.4%. A total of 214 cases were confirmed in the Venezuelan population (91% with no vaccination history); and 69 outbreaks with no epidemiological link were studied. The MVi/Hulu Langat.MYS/26.11[D8] lineage was identified. Endemic circulation was prevented through innovative interventions such as infection surveillance and control, immediate notification, prioritization of field visits, and transmission risk level criteria.

Conclusions

Colombia controlled measles outbreaks that resulted from imported cases, and it prevented endemic circulation, thereby maintaining certification of measles elimination in the country.

Concordancia y subregistro en la notificación de brotes de enfermedades transmitidas por alimentos en Colombia

Objetivos Determinar la concordancia y el subregistro entre la notificación de brotes en registros individuales y colectivos de enfermedad transmitida por alimentos, notificados al sistema de vigilancia en salud pública durante 2013.Métodos Análisis retrospectivo a partir de la revisión y depuración de las bases de datos de enfermedades transmitidas por alimentos de registros individuales y colectivos notificados al sistema de vigilancia en salud pública; se determinó la concordancia entre brotes notificados en cada registro por entidad territorial. A través del método captura–recaptura se estableció el subregistro de brotes notificados, estimando la pre- valencia para cada registro. Resultados El 38,4% de los brotes de enfermedades transmitidas por alimentos se noti- ficaron en ambos registros, el 11,3% en colectivo y el 50,3% en individual. Por medio del método de captura y recaptura, se estimaron 1 680 brotes (IC-95%; 1 632-1 730), se determinó que en registro individual se detecta el 77,5% y en colectivo el 43,3% de los brotes estimados, para un subregistro del 12,8% de brotes. Discusión Se estableció una baja concordancia entre ambos registros y un alto subre- gistro en registro colectivo al sistema nacional de vigilancia; lo que dificulta la detección de brotes y oportuna aplicación de medidas de mitigación y control.

Factores asociados a la nefropatía inducida por contraste en pacientes hospitalizados a quienes se les realizó tomografía axial computarizada

Introducción: la nefropatía inducida por medio de contraste es la tercera causa de insuficiencia renal aguda en pacientes hospitalizados. En múltiples estudios se ha observado que un factor importante para su desarrollo es el uso de medio de contraste vía intra-arterial y en las angiografías en general. Nuestro objetivo es identificar los factores asociados a nefropatía inducida por contraste en pacientes hospitalizados, a quienes se les realizó tomografía axial computarizada con medio de contraste yodado en una institución de salud de alta complejidad de Neiva, Colombia, durante el 2016.Materiales y métodos: se desarrolló un estudio de casos y controles no pareado con 108 pacientes, 36 casos y 72 controles hospitalizados llevados a tomografía axial computarizada diagnóstica o terapéutica con medio de contraste radiológico yodado.Resultados: los factores asociados con nefropatía inducida por medio de contraste encontrados en los pacientes hospitalizados llevados a TAC contrastada fueron, el sexo (hombre) (OR=3,22; IC=95 % 1,33 - 7,76; p=0,009), y el servicio de procedencia (hospitalización en sala general) (OR=0,26; IC=95 % 0,07 - 1,00; p=0,051).