First Report of Viral Pathogens WSSV and IHHNV in Argentine Crustaceans [Note]

The pathogenic penaeid shrimp viruses white spot syndrome virus (wSSv) and infectious hypodermal and hematopoietic necrosis virus (IhhNv) are reported for the first time from Argentina. They both occurred in wild crustaceans in Bahia Blanca Estuary, with wSSv detected by polymerase chain reaction (pCR) or real time quantitative pCR (qpCR) methods as infecting samples as high as 56% of the penaeid Artemesia longinaris Bate, 1888, 67% of the grapsoid Cyrtograpsus angulatus dana, 1851, and 40% of the introduced palaemonid Palaemon macrodactylus Rathbun, 1902. The highest detected copy number was 39,600 copies/μg dNA. IhhNv was tested for using pCR in only A. longinaris, in which it infected 30% of the sample. The presence or absence of cuticular white spots, diagnostic features of a chronic wSSv infection, was not a reliable indicator of wSSv detected by pCR or qpCR methods. The qpCR method was more sensitive than three pCR methods for detecting wSSv, presumably because of low copy numbers (< 103 copies/μg dNA) in several hosts. The low numbers may be related to temperature, season, IhhNv co-infection, or perhaps host. Introductions of the viruses could have originated from contamination by infected living animals, frozen products, or from alongshore currents from Brazil bringing the agents from as far away as 1700 or perhaps 5500 km. highly pathogenic penaeid shrimp viruses have caused severe losses to commercial shrimps in the northern countries of South America and are a threat to Argentina. One of two such viruses is referred to as white spot syndrome virus (wSSv), originating from Southeast Asia where it emerged in the western hemisphere in the mid 1990s. It had a severe impact on commercial penaeid aquaculture in 1999, first in Central America and then in Ecuador (e.g., Lightner, 2004). Infections spread south, finally to Brazil by late 2004 (available at http://www.oie.int/eng/info/hedbo/AIS_58. htm on 7 August 2009, previously on ftp://ftp.oie.int/infos_san_archives/eng/2005/ en_050121v18n03.pdf; Cavalli et al., 2008; Marques, 2008). This large double-stranded dNA virus in the nimavirid genus Whispovirus produces mortalities in several penaeid shrimp species as exemplified by the loss of about 10 billion US dollars attributed to wSSv infections in penaeid aquaculture (e.g., Lightner, 2004; Lo, 2006). Once established, the infections had an impact on wild crustaceans (e.g., SánchezMartínez et al., 2007). Another virus is infectious hypodermal and hematopoietic necrosis virus (IhhNv), which appeared to have reached the Americas from the philippines in the early 1980s (Tang et al., 2003b). It is abundant in shrimp farms in northeastern Brazil (Braz et al., 2009) and documented earlier from cultured pacific white shrimp, Litopenaeus vannamei (Boone, 1931), in southern Brazil (Moser, 2005). The virus can be fatal to 90% or more of some stocks of Litopenaeus stylirostris (Stimpson, 1874) and produce a runting syndrome in the giant tiger prawn, Penaeus monodon (Fabricius, 1798), and L. vannamei, reducing the latter’s market value by 10%–50% (Lightner and Redman, 1998). This small, non-enveloped, icosahedral, single-stranded linear dNA virus with virions averaging 22–23 nm in diameter is NOTE BULLETIN OF MARINE SCIENCE, vOL. 86, NO. 1, 2010 118 capable of vertical transmission through spawning females (Motte et al., 2003). It belongs to the family parvoviridae in the genus Brevidensovirus as Penaeus stylirostris densovirus (pstdNA) in the subfamily densoirinae (Shike et al., 2000; Tattersall et al., 2005). here we document Artemesia longinaris Bate, 1888 as a new wild host for wSSv and IhhNv, supported by histopathological sections and molecular polymerase chain reaction (pCR) and real time quantitative pCR (qpCR) methods. we also report two other crustacean hosts for wSSv, establishing the extension of geographic ranges of the crustacean viruses into Argentina, and comparing grossly visible white spots with confirmed wSSv cases.