A Seasonal Study of Koi Herpesvirus and Koi Sleepy Disease Outbreaks in the United Kingdom in 2018 Using a Pond-Side Test

摘要

Cyprinid herpesvirus (CyHV)-3 and carp edema virus (CEV), the causative agents of koi herpesvirus disease and koi sleepy disease, respectively, are emerging DNA viruses infecting koi and common carp. Similarities in their clinical presentation present difficulties for its on-site identification based on gross pathology. Fluorescence real-time loop-mediated isothermal amplification (LAMP) assays for detecting CyHV-3 and CEV DNA were designed to use border inspection posts and local testing by national authorities for outbreak control. The limit of these tests’ detection (102 and 103 viral copies for CyHV-3 and CEV, respectively) allows for the amplification of viral DNA in clinical samples in less than 20 min. The assays’ field performance was tested with 63 common carp mucus swabs taken during disease investigations in 2018, and the results validated with the reference laboratory analysis. Overall, the good performance, ease of use, and cost-effectiveness of these tests make them good candidates for a point of care test. However, further work is required to incorporate reliable internal controls and improve the sensitivity of these tests’ asymptomatic testing.