Direct transmission of SFTSV from dogs to humans: Molecular confirmation and risk assessment

This study aimed to investigate the potential for dog-to-human transmission of Severe Fever with Thrombocytopenia Syndrome Virus (SFTSV) and characterize viral shedding patterns in naturally infected dogs.

We conducted genomic analysis of SFTSV strains isolated from an infected dog and its owner using whole-genome sequencing. Viral loads were quantified in canine saliva, urine, and stool samples via qRT-PCR during the acute infection phase.

Genomic sequencing revealed 100% identity between viral strains from the dog and owner. The dog exhibited exceptionally high viral loads, particularly in bloody stools (2.2 × 10⁷ copies/mL) and saliva (2.3 × 10⁵ copies/mL), with persistent shedding observed throughout the clinical course. The owner developed SFTSV infection 14 days after the dog's symptom onset.

This study provides the first molecular confirmation of direct SFTSV transmission from dogs to humans, identifying bloody stools and saliva as high-risk transmission sources. These findings underscore the importance of including dogs in SFTSV surveillance systems and implementing protective measures when handling sick pets in endemic areas.