Transmission of white sturgeon iridovirus in Kootenai River white sturgeon Acipenser transmontanus

Abstract

It is thought that white sturgeon iridovirus (WSIV) is transmitted vertically from adult white sturgeon Acipenser transmontanus to progeny, and that wild adults are carriers of this virus. Based on this assumption, egg disinfection trials were initiated using wild Kootenai River white sturgeon. Over 2 consecutive years, post-fertilized eggs were disinfected with iodine at concentrations ranging from 0 to 400 ppm. Eggs were incubated and progeny were reared on either de-chlorinated municipal or Kootenai River water. Juvenile sturgeon (mean weight 3.0 g) from these treatment groups were then subjected to a density stress (15 or 20 g l -1

A new species of nucleo-cytoplasmic large DNA virus (NCLDV) associated with mortalities in Manitoba lake sturgeon Acipenser fulvescens

“…Initial attempts to isolate the virus in pure culture on white sturgeon cell lines were unsuccessful. This is similar to MRSIV (Kurobe et al 2011) and some isolates of WSIV (Hedrick et al 1990, Drennan et al 2006. We were able to detect Namao virus, although weakly, by cPCR when suspect tissues were inoculated and then incubated for prolonged periods on primary lake sturgeon cell lines but without evidence of CPE.…”

“…None of these possibilities can be ruled out from having occurred in the present study but, as we mentioned earlier, the presence of the virus in treated, municipal water seems unlikely, though not impossible. In fact, Drennan et al (2006) reported that the accidental introduction of as little as 100 ml of Kootenai River water resulted in fish testing positive for WSIV during the course of an experiment conducted in tanks receiving municipal water.…”

“…Adults can be refractory to clinical disease, but are likely subclinical carriers that may intermittently shed virus (Hedrick et al 1990, LaPatra et al 1994, Kurobe et al 2011. Horizontal transmission of WSIV and MRSIV from convalescent to naïve juvenile sturgeon has been demonstrated (Hedrick et al 1990, Drennan et al 2006, Kurobe et al 2011) and there are suggestions that egg-associated transmission from adult to offspring occurs during spawning (Hedrick et al 1992, LaPatra et al 1994, Georgiadis et al 2001. Handling, stocking density and fluctuations in water levels, flow rates, and/or temperature are among the other risk factors known to contribute to the onset and severity of these disease outbreaks (LaPatra et al 1994, Watson et al 1998a, Georgiadis et al 2000, Drennan et al 2005, 2006.…”

Ecopathology of Ranaviruses Infecting Amphibians

“…During an outbreak, it is likely that ranavirus infects hosts via multiple routes of horizontal transmission. Although vertical transmission of iridoviruses has been shown in invertebrates [139], it has not been demonstrated for ranaviruses infecting vertebrates [140]. Attempts to test for vertical transmission have yielded mixed results [36,109].…”

Characterization of serum and mucosal antibody responses in white sturgeon (Acipenser transmontanus Richardson) following immunization with WSIV and a protein hapten antigen

“…The eggs were incubated and hatched in virus-free water and the resulting progeny were monitored for the presence of WSIV. Previous transmission studies showed that these fish were not infected with WSIV [18]. Histopathology examinations performed on these fish showed no evidence of lesions associated with WSIV infection and no disease outbreaks occurred during this study.…”