Detection of channel catfish virus DNA in acutely infected channel catfish, Ictalurus punctatus (Rafinesque), using the polymerase chain reaction

Abstract

Channel catfish virus (CCV) causes an acute haemorrhagic disease in channel catfish, Ictalurus punctatus (Rafinesque), fry and fingerlings. The present study describes a polymerase chain reaction (PCR)‐based assay for detection of CCV DNA in the tissues of acutely infected juvenile catfish. The assay is rapid, sensitive and specifically detects CCV DNA derived from epidemiologically distinct viral isolates. The use of two independent PCR primers sets, each specific for particular CCV genes (open reading frames 8 and 59), provides a means to confirm the results and minimize false‐positive results. The method identifies CCV DNA in several tissues of acutely infected fish, including the brain, blood, intestine, kidney and liver. The CCV PCR assay is useful for the diagnosis of acute CCV disease and for studies to investigate the molecular basis of CCV pathogenesis.

Detection of channel catfish virus DNA in latently infected catfish.

“…Serological assays, such as serum neutralization, may not be reliable for identifying latently infected fish in catfish populations (Amend & McDowell, 1983. The standard and nested set CCV PCR assays described in this and our previous study (Gray et al, 1999) are specific and sensitive and will be useful in epidemiological studies to screen catfish populations for CCV DNA detection.…”

“…PCR products and markers were analysed by agarose gel electrophoresis and ethidium bromide staining. catfish DNA (the amount of catfish DNA in $ 55 000 cells) (Gray et al, 1999). However, the orf 8 PCR assay could only detect CCV DNA in tissues of 50 % (three of six tested) of fish that survived primary CCV infection and were suspected of being latently infected.…”

“…We recently reported a specific and sensitive PCR based assay for detection of CCV DNA in tissues of acutely infected catfish (Gray et al, 1999). In this study, we utilize an experimental model for CCV disease and PCR analysis to detect CCV DNA in tissues of catfish which survive primary disease.…”

Concentrations of a Koi herpesvirus (KHV) in tissues of experimentally-infected Cyprinus carpio koi as assessed by real-time TaqMan PCR

“…The important role of cutaneous tissues in herpesvirus infections are known from most animals including fish (Hedrick & Sano 1989). An initial and then persistent involvement of the skin and gills has been observed with channel catfish (Ictalurus punctatus) infected with IcHV-1, carp infected with CyHV-1 and Japanese eels (Anguilla japonica) infected with Anguillid herpesvirus 1 (Wise & Boyle 1985, Nusbaum & Grizzle 1987, Sano et al 1993, Baek & Boyle 1996, Kobayashi & Miyazaki 1997, Gray et al 1999a,b, Lee et al 1999. A systemic spread of virus, perhaps from initial sites in the skin and gills to numerous internal organs and nervous tissue occurs with the herpesviruses from catfish, carp, and eels and most likely with KHV.…”

Detection of the herpesviral hematopoietic necrosis disease agent (Cyprinid herpesvirus 2) in moribund and healthy goldfish: validation of a quantitative PCR diagnostic method

“…These latently infected fish are anecdotally implicated in the spread of KHV to new populations. Channel catfish herpesvirus (CCV or IcHV-1) produces latent infections in channel catfish surviving acute infections (Gray et al 1999, Stingley et al 2003 and the virus may even be vertically transmitted (Hanson et al 2004).…”