The commercially important penaeid shrimp A. longinaris was collected from Bahia Blanca Estuary, Argentina (Fig. 1; 38°46´S, 62°20´w). Samples of about 40 individuals of both A. longinaris and the solenocerid penaeoidean Pleoticus muelleri (Bate, 1888) (Argentine red shrimp) were purchased fresh at the Ingeniero white port each year from 2003 to 2008, usually in February–March. These shrimps were captured by relatively large commercial vessels trawling channels of the estuary. Individual shrimp were kept on ice and examined grossly for signs of wSSv, and two or three representatives of each yearly sample were immediately fixed and sectioned. Also in February and March of 2008, a total of 20 live specimens of A. longinaris were collected by cast net from a pier at general daniel Cerri, an oligohaline region of the Estuary. An additional 20 live specimens were obtained from commercial vessels. These live shrimp were transported to the laboratory in plastic bags with aerated sea water from the source. After viral infections were confirmed, additional specimens from general daniel Cerri were collected and the gills immediately fixed in 95% molecular grade ethanol
for molecular analyses.