Infestation measured by Aedes aegypti larval surveys as an indication of future dengue epidemics: an evaluation for Brazil. (29th April 2020)

• Record Type: Journal Article
• Authors: Enslen, Andrew W; Lima Neto, Antonio S; Castro, Marcia C
• Is Part Of: Transactions of the Royal Society of Tropical Medicine and Hygiene. Volume 114:Number 7(2020)
• Page Start: 506
• Page End: 512
• Publication Date: 2020-04-29
• Subjects: Aedes aegypti -- dengue -- house index -- rapid larval survey; Tropical medicine -- Periodicals; 616.9883
• DOI: 10.1093/trstmh/traa021
• Languages: English
• ISSNs: 0035-9203

Abstract

Abstract: Background: Aedes aegypti rapid larval surveys are mandatory in Brazil. Here, we retrospectively examined whether the house index estimated by larval surveys served as a useful tool in anticipating epidemics within Brazilian municipalities from 2009–2015. Methods: We used correlation indices and classification analysis stratified by year, region, population size and time after the national larval survey. Results: We found no association between the house index and the proportion of municipalities experiencing an epidemic. The sensitivity of a high score house index in predicting an epidemic was 7.20% (95% CI 6.22 to 8.33%) for all years combined. The positive predictive value of a high score house index to predict a 'true epidemic' was 38.96%, lower than the negative predictive values of a low score house index for predicting 'no epidemic' (56.96%). The highest overall sensitivity was observed in the North region (20.15%; 95% CI 17.14 to 23.53%). The sensitivity of a high score house index demonstrated a monotonic decrease with increasing time from larval collection. Conclusions: Larval surveys are surveillance tools with the potential to risk-stratify and guide dengue control programs towards judicious resource allocation. However, the national rapid larval survey performed in Brazil, in its present form, consistently underpredicts dengue epidemics.