Cyprinid herpesvirus 3 as a potential biological control agent for carp (Cyprinus carpio) in Australia: susceptibility of non‐target species

Abstract

Carp (Cyprinus carpio L.) is a pest species in Australian waterways, and cyprinid herpesvirus 3 (CyHV-3) is being considered as a potential biological control (biocontrol) agent. An important consideration for any such agent is its target specificity. In this study, the susceptibility to CyHV-3 of a range of non-target species (NTS) was tested. The NTS were as follows: 13 native Australian, and one introduced, fish species; a lamprey species; a crustacean; two native amphibian species (tadpole and mature stages); two native reptilian species; chickens; and laboratory mice. Animals were exposed to 100-1000 times the approximate minimum amount of CyHV-3 required to cause disease in carp by intraperitoneal and/or bath challenge, and then examined clinically each day over the course of 28 days post-challenge. There were no clinical signs, mortalities or histological evidence consistent with a viral infection in a wide taxonomic range of NTS. Furthermore, there was no molecular evidence of infection with CyHV-3, and, in particular, all RT-PCRs for viral mRNA were negative. As a consequence, the results encourage further investigation of CyHV-3 as a potential biocontrol agent that is specific for carp.

News

“…A recent IA-CRC-supported study 14 clearly demonstrated the species-specificity of CyHV-3 and also questioned results of previous specificity studies. An independent review will soon inform whether further species-specificity work is required.…”

Current knowledge and future prospects of vaccines against cyprinid herpesvirus 3 (CyHV-3)

“…[2]), disease is only diagnosed in common and koi carp and related hybrids [39]. Nevertheless, the susceptibility of additional fish species to CyHV-3 is still highly controversial [40,41]. However, the possibility that the attenuated vaccine strain may infect cohabitant common carp not primarily targeted by the vaccination has been investigated [36].…”

Biocontrol of Carp: The Australian Plan Does Not Stand Up to a Rational Analysis of Safety and Efficacy

“…The biological relevance of these data should be taken with caution as the signals observed were weak and the transmission to sentinel carp was never associated with the expression of CyHV-3 disease. The risk of CyHV-3 infecting non-target species of Australia was investigated in limited experimental conditions in a recent paper (McColl et al, 2017). Importantly, the results of that study indicate that CyHV-3 may have induced mortality in at least some native fish species [e.g.…”