# Detection of Enteroviruses on Environmental Surfaces in Daycare Centers Using Droplet Digital PCR (ddPCR) and Its Public Health Implications

## TL;DR

This study found that enteroviruses are commonly present on surfaces in daycare centers, and using a more sensitive detection method like ddPCR can help track their spread.

## Contribution

The study demonstrates the superior sensitivity of ddPCR over real-time RT-PCR for detecting low-level enterovirus contamination on surfaces.

## Key findings

- Enteroviruses were detected in 45.3% of environmental samples collected from daycare centers.
- ddPCR detected enteroviruses at nearly twice the rate of real-time RT-PCR, highlighting its sensitivity to low-level contamination.
- Floors were the most contaminated surfaces, and detection rates decreased over time with improved hygiene practices.

## Abstract

Enteroviruses (EVs) are major pathogens transmitted via direct and indirect contact, with children being particularly susceptible. As EVs persist on surfaces, environmental hygiene is critical in communal environments. We investigated EVs presence on environmental surfaces in daycare centers from April to July 2024. Environmental samples (300) were collected from floors, toys, and desks. Viral RNA was extracted and analyzed using real-time reverse transcription polymerase chain reaction (real-time RT-PCR) and ddPCR to detect pan-Enterovirus (pan-EVs) and Enterovirus D68 (EV-D68). EVs were detected in 45.3% of the samples. The detection rate refers to the combined results, including both ddPCR and real-time PCR. Specifically, pan-EVs were found in 88 samples (1.12–505 copies/20 μL) and EV-D68 in 104 samples (1.12–309 copies/20 μL). Floors (31%) were the most contaminated surfaces. Monthly analysis showed a gradual decrease in detection rates from 88.6% in April to 18.5% in July, appearing to align with the implementation of enhanced hygiene measures. However, this trend may also reflect multifaceted factors, including natural viral reduction, exclusion of symptomatic children, and increased hygiene awareness. Notably ddPCR (83.0%) exhibited nearly twice the detection rate of real-time RT-PCR (42.5%), identifying low-level viral persistence. These findings suggest that environmental surfaces serve as reservoirs for transmission, and integrating sensitive detection like ddPCR with proactive hygiene management may help mitigate EVs spread.