# Development of an RT-qPCR Assay for the Detection of an Emerging Duck Egg-Reducing Syndrome

## TL;DR

Researchers developed a sensitive and specific RT-qPCR test to detect a virus causing reduced egg production in ducks, which could help control its spread and economic impact.

## Contribution

A novel RT-qPCR assay was developed for the specific and sensitive detection of Duck Egg-Reducing Syndrome Virus (DERSV).

## Key findings

- The RT-qPCR assay detected DERSV with a limit of 102 copies and a linear range from 102 to 109 copies per reaction.
- The assay showed 92.59% efficiency and less than 2% coefficient of variation for both intra- and inter-assays.
- Among 153 clinical samples, 47.06% tested positive for DERSV using the developed RT-qPCR method.

## Abstract

Duck egg-reducing syndrome virus (DERSV), a novel Avihepatovirus, causes a gradual decline in duck egg production. Early detection of infected ducks is essential for preventing the spread of the virus and minimizing its economic impact. This study developed a quantitative reverse transcription PCR (RT-qPCR) assay for DERSV detection, which was validated for high sensitivity, specificity, and reliability. This method offers significant potential for use in epidemiological and pathogenesis studies.

Duck egg-reducing syndrome virus (DERSV) is a novel Avihepatovirus and is responsible for a gradual decline in the laying rate of ducks, decreasing from a peak of 90% to 50%. The development of a rapid detection method for DERSV is crucial for the identification and control of virus infections. In this study, we developed a quantitative reverse transcription PCR (RT-qPCR) assay for detecting DERSV. Specific primers and a probe were designed to target a conserved region of the 3D gene. The assay demonstrated high specificity, with no cross-reactivity to other non-target duck viruses. It had a detection limit of 102 copies and a linear range from 102 to 109 copies per reaction. The assay’s efficiency was 92.59%, with a regression coefficient (R2) of 0.999. The coefficient of variation for both intra-and inter-assays was less than 2.00%. Among the 153 clinical samples collected from 2016 to 2023, the RT-qPCR detected a DERSV positive ratio of 47.06% (72/153). In conclusion, the utilization of the real-time RT-qPCR assay holds potential for the detection of DERSV in epidemiological and pathogenesis studies.