Comportamiento poblacional de larvas de Aedes aegypti para estimar los casos de dengue en Yurimaguas, Perú, 2000 - 2004

Abstract

Objectives: To study the population behavior of Aedes aegypti larvae in order to explain its fluctuations using three entomological indexes and estimate dengue fever cases in Yurimaguas, Loreto, Peru. Materials and methods: Data from 100% larval counts for the three-year study period was collected using three entomological indexes: Aedes index, Recipient index and Breteau index, as well as monthly native cases of dengue fever from the Epidemiology Office in Yurimaguas Hospital. Spearman’s correlation test was used for assessing the relationship between the three entomological instruments and dengue fever cases, and ultimately regression equations were used for estimating the number of dengue fever cases occurring between 2000 and 2004 from the entomological indicators. Results: Monthly average values for Aedes index, Recipient index and Breteau index were 4,03 ± 1,85; 1.31 ± 1,07; and 4,88 ± 2,31, respectively. The three entomological indexes showed differences between the eighteen assessments performed from 2000 to 2004. There was a trend for a reduction in the aforementioned indexes from April 2000 to July 2003, and a mild increase from December 2003 to December 2004. Average monthly number of dengue fever cases throughout the study was 8,11 ± 6,66. All the indexes were linearly and positively highly correlated between 2000 and 2004. Four equations capable of estimating the number of dengue fever cases were constructed, only using the Aedes index. Conclusions: Using the data obtained after five years’ assessment, four valid regression models are proposed for estimating the total monthly number of dengue fever cases using the Aedes index as baseline. The equation: log (total of dengue fever cases) + 1) = 0,50 + 0,44 (log Aedes index + 1) was the most appropriate for estimating the monthly number of dengue fever cases.