Climatic thresholds associated with increased dengue incidence across climate zones in Peru (2001-2022)

Introduction

Dengue fever has experienced a global rise in incidence and distribution, largely influenced by climate variability. Nonetheless, the specific climatic thresholds that trigger elevated dengue incidence rates, and the time lag between weather conditions and the case surges remain uncertain.

Methods

Average weekly climate variables along with weekly dengue incidence rates from 2001 and 2022 were analyzed in districts grouped by its climate zone. A cross-correlation technique was used to determine the time lag between climatic variables and dengue incidence, while a fine-tuned regression tree model was utilized to identify climatic thresholds linked to the incidence of dengue surges.

Results

Our findings indicate that specific combinations of climatic thresholds within each climate zone are associated with increased dengue incidence rate over a 20-week window, with air temperature having a frequent role. The North Coast had the highest average dengue incidence, with rates surging sevenfold when climatic thresholds were met (56 cases per 100,000 inhabitants). The Central Coast and North-High Rainforest zones experienced the most significant increases, with incidence rates rising 53-fold from baseline levels (0.13 cases and 2.4 cases per 100,000, respectively).

Conclusions

This study identified distinct climatic thresholds that were met within a 20-week window preceding elevated dengue incidence rates in the six climate zones with the highest dengue prevalence in Peru. These insights enable dengue incidence rates forecasting weeks in advance using climatic data, offering a valuable tool for dengue mitigation and early intervention.