Differential host passaging alters pathogenicity and induces genomic variation in white spot syndrome virus

White spot syndrome virus (WSSV) genome stability maintained over six passages through three different penaeid shrimp species

“…The stability of ORF94, ORF125 and ORF75 VNTRs in the 2 WSSV strains examined here contrasts with the ORF94 instability reported previously among WSSV strains following a single passage of various strains in the same or different penaeid shrimp species, as well as other less susceptible crustacean hosts (Waikhom et al 2006). In contrast, passaging of the WSSV PmTN4RU P. monodon strain and the LvAP11RU L. vannamei strain examined here in P. monodon, L. vannamei and F. indicus followed by multiple passages in the same species had no affect on their VNTR makeup.…”

“…While it has been re ported that a single passage of various WSSV strains in a different crustacean host can promote a shift in VNTR type (Waikhom et al 2006), a very recent study found the ORF94 VNTR to be unaltered following several serial passages through 3 diverse crustacean host species (Gudkovs et al 2014). As stable VNTR types have been identified among susceptible crustaceans sampled from aquaculture ponds containing WSSVinfected shrimp (Hoa et al 2011), it appears likely that the rapid shifts in VNTR type reported by Waikhom et al (2006) were due to host selection of a WSSV genetic variant present in low levels and not de tected in the parental tissue used for challenge, or to the detection of a WSSV type pre-existing at low levels and/or prevalence in the less-susceptible host species challenged. Thus, to examine more closely what potential impacts host and passage number might impart upon VNTR stability, and to reaffirm how VNTR marker data can be interpreted in epidemiological studies, 2 WSSV strains with different VNTR genotypes were passaged sequentially through 3 different penaeid shrimp species.…”

Analysis of variable genomic loci in white spot ­syndrome virus to predict its origins in Procambarus clarkii crayfish farmed in China

“…However, due to consumer demand and its high commercial value, P. clarkii has now become an important freshwater aquaculture species farmed widely across inland China, and WSD has become a major problem for this industry (Wang et al 2007, Ding et al 2008, Xu et al 2008, Liang et al 2010. To assist in identifying the root sources of WSSV infection in crayfish farmed in China and devising strategies to control its spread Despite associations between the pathogenicity and protein profiles of WSSV isolates examined from different hosts (Wang et al 1999, 2000, Waikhom et al 2006, the factors dictating virulence are likely to be complex. Genome sequence data on WSSV isolates from different penaeid shrimp species, as well as the blue crab Callinectes sapidus, suggest they have a common recent ancestry (Chang et al 2001, Chen et al 2002, Moon et al 2003, Dieu et al 2004.…”

“…It is interesting that whilst WSD spread rapidly and widely elsewhere, with reports of it occurring in freshwater crayfish and cultured stocks of Penaeus vannamei, P. stylirostris and P. setiferus in the USA as early as 1995 , Richman et al 1997, outbreaks in P. clarkii farmed in China were delayed by some 15 yr after WSSV first impacted the local penaeid shrimp culture industry. As variations in pathogenicity and viral protein profiles have also been detected amongst WSSV isolates originating from different hosts (Wang et al 1999, 2000, Waikhom et al 2006, analysis of variable genomic loci to determine the genetic relatedness of WSSV types derived from crayfish and shrimp should shed light on its origins and the dissemination mechanisms potentially useful in defining disease control strategies.…”

Analysis of repeated compound units in ORF94 of white spot syndrome virus isolated from Litopenaeus vannamei from outbreak and non outbreak shrimp farms in Sonora, Mexico

“…This region shows more variation, with a wide range of compound repeat units (RUs) between the WSSV isolates originating from farming and wild hosts (Wongteerasupaya et al, 2003;Dieu et al, 2004;Musthaq et al, 2006;Pradeep et al, 2008;John et al, 2010;González-Galaviz et al, 2013). Several studies have suggested a correlation between the RUs of ORF94 and WSSV virulence as follows: the fewer RUs (<9) the higher mortality rate in shrimps (Waikhom et al, 2006;Pradeep et al, 2008;Hoa et al, 2012). However, there is little evidence in the analysis of samples from non-outbreak ponds (Wongteerasupaya et al, 2003;Hoa et al, 2005;Musthaq et al, 2006).…”