Resurgimiento de la Fiebre Amarilla: Diagnóstico clínico precoz en humanos y Vigilancia Epizoótica en el Contexto Suramericano

INTRODUCTION: Yellow fever is undergoing a resurgence in the Americas, with 235 human cases and a 41% case fatality rate reported as of May 25, 2025. OBJECTIVE: To review the current epidemiological landscape of yellow fever and evaluate the limitations of conventional diagnostic methods versus emerging molecular technologies for optimizing outbreak surveillance and response. METHODS: Narrative review of scientific literature (2015-2025) across PubMed, Scopus, Web of Science, LILACS, and SciELO, including 55 validated primary studies organized into four thematic axes. RESULTS: Conventional diagnostics are limited by IgM/IgG serological cross-reactivity with flaviviruses, post-vaccination antibody persistence up to 4 years, and RT-PCR’s ≤14-day detection window requiringspecialized laboratories. Emerging solutions include: digital PCR for absolute quantification of viral RNA at ultra-low loads in epizootics with incipient viremia; RT-LAMP for field-deployable detection within 1 hour with 10-fold higher sensitivity (LOD 0.29-12 PFU/mL) without thermal cyclers; CRISPR-dx (SHERLOCK/DETECTR) for ultra-rapid sequencespecific detection with low-cost potential, though still experimental for flaviviruses; and NGS/metagenomics for strain characterization and differentiation of wild-type from vaccine-derived viruses. CONCLUSIONS: Urgent diagnostic modernization is needed. Emerging technologies address critical sensitivity and specificity gaps, but require strengthened Latin American laboratory networks, validated integrated algorithms, and coordinated crossborder responses to contain yellow fever re-emergence.