Primary diagnosis and surveillance of white spot syndrome virus in wild and farmed crawfish (Procambarus clarkii, P. zonangulus) in Louisiana, USA

Abstract

This is the first report of natural white spot syndrome virus (WSSV) infection in wild and large-scale farmed crawfish. In the spring of 2007, 3 crawfish farms experienced heavy mortality in ponds populated by Procambarus clarkii and P. zonangulus. Histological examination revealed findings consistent with severe viral infection characterized by numerous intranuclear inclusions in ectodermal and mesodermal tissues. Samples tested by in situ hybridization, injection bioassay in Litopenaeus vannamei, and PCR (nested and real time) were all positive for WSSV. Samples were sent to the National Veterinary Services Laboratory in Ames, Iowa, USA, where WSSV was verified. Subsequently, a multi-parish survey of 184 sites in Louisiana (including farm and wild basin samples) using real-time PCR determined that > 60% of sites sampled were positive for WSSV, including wild basin samples.

Disease will limit future food supply from the global crustacean fishery and aquaculture sectors

“…Jones (2012) describes several instances where the translocation of important viral pathogens to new locations was not due to the movement of live animals. These include the outbreak of WSSV in Darwin, Australia in 2000 (East et al, 2004) and the outbreak of WSSV in Louisiana crawfish ponds in 2009 (Baumgartner et al, 2009). Furthermore, he states that in addition to the direct use of raw frozen products as aquarium/farm animal feeds, other potential pathways of introduction include discarded waste from crustacean processing plants, the use of commodity shrimp as angling baits, or even by industrial sabotage.…”

Surveillance for infectious myonecrosis virus in Indian shrimp aquaculture

“…The first step of RT-PCR can generate results in an infection with a minimum of 100 IMNV copies and the nested RT-PCR can detect up to 10 IMNV copies (OIE, 2012). Baumgartner et al (2009) used the nested RT-PCR technique for the primary diagnosis and surveillance of WSSV in wild and farmed crawfish (Procambarus clarkii and Procambarus zonangulus) in Louisiana, USA along with the shrimp bioassays and real-time PCR. They followed the same protocol as suggested by OIE (Baumgartner et al, 2009).…”

“…Baumgartner et al (2009) used the nested RT-PCR technique for the primary diagnosis and surveillance of WSSV in wild and farmed crawfish (Procambarus clarkii and Procambarus zonangulus) in Louisiana, USA along with the shrimp bioassays and real-time PCR. They followed the same protocol as suggested by OIE (Baumgartner et al, 2009). The same RT-PCR method has evidently proven its sensitivity in the case of longitudinal surveillance survey of human picornavirus infection in children with weekly sampling protocol (Winther et al, 2006).…”

Disease risks associated with the importation and release of non-native crayfish species into mainland Britain

“…(Bi et al 2008) and white spot syndrome virus (WSSV) (Du et al 2008). Baumgartner et al (2009) noted the presence of WSSV in wild populations of P. clarkii in the USA.…”