IN-VIVO REPLICATION OF CYPRINID HERPESVIRUS-3 IN GOLDFISH

Abstract

Cyprinid herpes virus-3 (CyHV-3) is the causative agent of the lethal, highly contagious and notifiable koi herpesvirus disease (KHVD) in common carp and koi. Since its first identification, outbreaks of KHVD have occurred worldwide with significant economic losses in common carp and ornamental koi aquaculture industries. In the present study, experimental infection of goldfish by immersion rout was established. Apparently healthy common carp and goldfish were exposed to various concentrations of the CyHV-3 and monitored for mortality and development of clinical signs. CyHV-3 DNA was detected in the tissues of the challenged goldfish and common carp, which confirm the suitability of the immersion route to be used for infection of goldfish with CyHV-3. In addition, CyHV-3 terminase gene was amplified from the RNA extracted from the goldfish gill tissues at two-and eight-days post exposure to CyHV-3. The primer set used for amplification of this gene is specific for RT-PCR and did not amplify this gene from DNA. Results of this investigation confirm the replication of CyHV-3 in the goldfish tissues, which act as a true carrier not a vector or fomites and establish the experimental infection of goldfish with CyHV-3 by immersion route.