Assessment of the relationship between entomologic indicators of Aedes aegypti and the epidemic occurrence of dengue virus 3 in a susceptible population, São José do Rio Preto, São Paulo, Brazil

Abstract

The aims of this study were to describe the occurrence of dengue in space and time and to assess the relationships between dengue incidence and entomologic indicators. We selected the dengue autochthonous cases that occurred between September 2005 and August 2007 in São José do Rio Preto to calculate incidence rates by month, year and census tracts. The monthly incidence rates of the city were compared to the monthly Breteau indices (BI) of the São José do Rio Region. Between December 2006 and February 2007, an entomological survey was conducted to collect immature forms of Aedes aegypti in Jaguaré, a São José do Rio Preto neighborhood, and to obtain entomological indices. These indices were represented using statistical interpolation. To represent the occurrence of dengue in the Jaguaré neighborhood in 2006 and 2007, we used the Kernel ratio and to evaluate the relationship between dengue and the entomological indices, we used a generalized additive model in a spatial case-control design. Between September 2005 and August 2007, the occurrence of dengue in São José do Rio Preto was almost entirely caused by DENV3, and the monthly incidence rates presented high correlation coefficients with the monthly BI. In Jaguaré neighborhood, the entomological indices calculated by hectare were better predictors of the spatial distribution of dengue than the indices calculated by properties, but the pupae quantification did not show better prediction qualities than the indices based on the container positivity, in relation to the risk of dengue occurrence. The fact that the municipality's population had a high susceptibility to the serotype DENV3 before the development of this research, along with the almost total predominance of the occurrence of this serotype between 2005 and 2007, facilitated the analysis of the epidemiological situation of the disease and allowed us to connect it to the entomological indicators.

Using adult Aedes aegypti females to predict areas at risk for dengue transmission: A spatial case-control study

“…The main argument for the use of the clinical and epidemiological criteria during a situation of strong dengue transmission refers to the increase in dengue prevalence. Consequently, the probability that a suspected dengue case tends to be a real positive dengue case also increases, since the positive predictive value increases (Fletcher et al, 2014;Chiaravalloti-Neto et al, 2015). Besides, more than 70% of the positive cases and all negative cases were confirmed by laboratory assays, which minimizes the limitation to the point where the association found between the proposed entomological index and occurrence of dengue in fortnights 6-7/2013 onwards are also valid.…”

“…A population completely or partially susceptible to a specific serotype combined with its prevalence is adequate to evaluate a new entomological index and its correlation with disease occurrence. It minimizes the bias of the population immunity to the specific serotype (Chiaravalloti-Neto et al, 2015). Thus, we were able to evaluate an entomological method that can predict risk areas for dengue in a susceptible population.…”

“…These traps are as effective as human bait collection, and are more effective than manual aspirators (Figueiredo et al, 2013;Hapairai et al, 2013;Maciel-de-Freitas et al, 2006. Other tools to detect high-risk clusters in a given area are Geographical Information Systems (GISs) and spatial analysis techniques, as demonstrated by Barbosa et al (2014) and Chiaravalloti-Neto et al (2015).…”

Dengue virus serological prevalence and seroconversion rates in children and adults in Medellin, Colombia: implications for vaccine introduction

“…Although it was outside the scope of this study, the assessment of neighborhood-specific strategies for vector control and other environmental characteristics might have been helpful for understanding the relatively homogeneous distribution of DENV prevalence and the more variable behavior for seroconversion. In Latin America, risk assessment by environmental (including entomological evaluation), socioeconomic, and health care access characteristics has been considered a useful tool to identify the dengue burden 15, 25, 34, 35. Moreover, comparing neighborhoods or other small geographic units to identify areas with dengue is key to address vector control and other targeted strategies for disease control 11, 15, 19, 25, 31…”

Características da epidemia de dengue em Pinhalzinho, Santa Catarina, 2015-2016*

“…9,10,12 It should be noted that although all age ranges are equally susceptible, elderly people have more risk of developing dengue with alarm signs and severe dengue with the possibility of leading to death. 4 The temporal analysis indicated that the dengue cases followed a seasonal pattern of occurrence: they began in December and January and reached greatest incidence in February and March, coinciding with the Seasonal patterns such as this, with increased case occurrence in the early months of the year, have been found in municipalities in the states of São Paulo, 9,14,15 Piauí, 16 Rio de Janeiro 17 and Santa Catarina. 18 Increased mean temperature and relative humidity of the air were, together, capable of predicting 59.4% of infestation by the vector.…”