Integrated Surveillance Strategies and Clinical Characteristics of Arboviral Diseases in a Pediatric Cohort in Merida, Mexico, 2021-2023.

Dengue, chikungunya, and Zika are Aedes-borne diseases (ABDs) of global health significance. Epidemiological studies with sensitive case detection are critical for evaluating vector control strategies to prevent ABDs; however, data on which surveillance method is most effective are limited. The performance of five surveillance methods (home visits, phone calls, SMS reminders, toll-free phone line (TF) and the Ministry of Health surveillance platform) was assessed, and the clinical characteristics of ABD cases in the targeted indoor residual spraying trial, which quantified the efficacy of preventive indoor residual insecticide applications against ABDs in Merida, Mexico, were described. A cohort of 4,461 children was monitored over three transmission seasons (July-December 2021-2023), with surveillance methods rotated weekly to detect illnesses. Kaplan-Meier curves and log-rank tests compared the time from symptom onset to laboratory testing across methods. Analysis of variance, t- and χ2 tests assessed differences in utilization of surveillance methods across demographic factors. Of 1,902 illnesses detected, 920 (48.4%) met suspected ABD criteria; 825 provided blood samples (89%), and 422 (51%) were confirmed as ABDs. Dengue represented 70.4% of confirmed cases (n = 297/422). Among confirmed cases, clinical manifestations were diverse, with fever (>94%), myalgia (80-100%), and headache (70-100%) being most frequent. Twenty-seven patients (9%; n = 27/297) had dengue with warning signs. TF detected 55.2% (n = 233/422) of confirmed cases and achieved the fastest time to laboratory testing. These results demonstrate case detection can be optimized. TF proved effective in rapidly identifying symptomatic reports, underscoring the value of integrated, low-barrier reporting systems for early arboviral detection.