Dengue and chikungunya viruses among febrile travelers entering Iran (2015-2021): Evidence of multiple introductions from different countries.

OBJECTIVES

Recent outbreaks of dengue, chikungunya, and Zika have underscored the growing threat to public health. This study retrospectively describes the presence of these viruses among febrile travelers entering Iran between 2015 and 2021. Although Iran had no local transmission until 2024, several factors increased the risk of outbreaks, including the presence of mosquito vectors, favorable climate, and inadequate traveler control measures. Climate change and increased humidity have further increased this risk.

METHODS

A multiplex real-time reverse transcription-polymerase chain reaction assay was used to screen 245 serum samples from febrile travelers, identifying dengue and chikungunya viruses in 13.9% of the travelers.

RESULTS

Dengue was more prevalent (9%) than chikungunya (4.9%), but no Zika infections were detected. Genetic analysis identified three dengue virus (DENV) serotypes (DENV-1, DENV-2, and DENV-3) and an Asian genotype of chikungunya virus-like strains from the 2017 outbreak in Pakistan. Pakistan was the primary source of chikungunya (100%) and a significant source of dengue (37%). Travelers from Southeast Asia also contributed to the remaining dengue cases.

CONCLUSIONS

This study highlights the risk of importing dengue and chikungunya viruses into Iran, particularly through the land border with Pakistan. The endemicity of these viruses in neighboring countries and high cross-border movement significantly increase the risk of outbreaks in Iran.