Comparison of epizootic haematopoietic necrosis and Bohle iridoviruses, recently isolated Australian iridoviruses

Abstract

ABSTRACT. Epizootic haematopoletic necrosis virus (EHNV) and Bohle virus (BIV) are piscine and amphibian iridoviruses respectively which have been isolated in Australia from redfin perch Perca fluviatjlis L., cultured rainbow trout Oncorhynchus mykiss (Walbaum) and the ornate burrowing frog Limnodynastes ornatus (Gray). To determine whether the viruses were similar they were examined at the ultrastructural, protein, antigenic and genomic levels. EHNV was found to differ from BIV in cytopathic effect on host cells, size, site of virus release, molecular weights of proteins and restriction endonuclease digest profiles of the respective DNA's. On the other hand both iridoviruses \yere also found to infect a similar range of tissue culture cells, exhibit a similar sequence of ultrastuctural events and possess proteins of similar antigenic reactivity. DNA from EHNV and BIV cross hybridized to a high level. When the BIV polypeptides were compared to the published data for purified frog virus 3 (FV3) and with the appropriate restriction enzyme profiles, a similarity was noted between the 2 viruses. This implies that EHNV, which shares many structural and biochemical characteristics with BIV, is itself related to the Ranavirus genus of iridoviruses.

Comparative Pathology of Ranaviruses and Diagnostic Techniques

“…Ariel ( 1997 ) utilized methods developed by Hengstberger et al ( 1993 ) to detect anti-Bohle iridovirus (BIV) antibodies in wild reptiles in Australia. More recently, Johnson et al ( 2007Johnson et al ( , 2010 and Allender ( 2012a ) used ELISA for surveillance and laboratory investigations to test for the presence of anti-ranavirus antibodies in plasma of various chelonians in the USA.…”

“…8 ). Additional approaches have been developed to detect EHNV and European catfi sh virus (ECV) antigen using polyclonal antisera in Ag-capture ELISA and immunoelectronmicroscopy (Steiner et al 1991 ;Hengstberger et al 1993 ;Hyatt et al 1991 ;Whittington and Steiner 1993 ;Ahne et al 1998 ). Secondary antibodies suitable for immunofl uorescence or enzymatic detection enable the detection of ranavirus antigens in tissue sections and cell cultures (Reddacliff and Whittington 1996 ).…”

A polymerase chain reaction (PCR) to detect epizootic haematopoietic necrosis virus and Bohle iridovirus

“…fish lymphocystis disease virus, FLDV) and a fifth proposed 'goldfish group' (Francki et al 1991). Recent studies have compared EHNV with iridoviruses from the sheatfish Silurus glanis, the catfish Ictalurus melas and FV3 (Hedrick et al 1992, Hengstberger et al 1993. These studies showed that EHNV, BIV and FV3 belonged to the genus Ranavirus as do the sheatfish and catfish viruses (Essani & Granoff 1989, Hedrick et al 1992, Hengstberger et al 1993.…”

“…Since then, epizootics have been reported within wild redfin population~ in 3 Australian states [Victoria, New South Wales (NSW) and South Australia] and in cultured rainbow trout Oncorhynchus rnykiss (Walbaum) (Hengstberger et al 1993, Whittington et al 1994). The virus is also known to cause disease experimentally in a range of Australian native fish (Langdon 1989).…”

“…Antibodies have been raised against each of these isolates in addition to BIV , Steiner et al 1991, Hengstberger et al 1993, Whittington & Steiner 1993 and used in diagnostic tests such as antigen capture ELISA and immunoelectron microscopy. When polyclonal antibodies against EHNV are applied to Western blots they can demonstrate differences in the molecular weights of some of the structural proteins (e.g.…”