CEPAVE   05420
CENTRO DE ESTUDIOS PARASITOLOGICOS Y DE VECTORES
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Shell disease in the grapsid crabs Cyrtograpsus angulatus and Neohelice granulata from Bahía Blanca estuary, Argentina
Autor/es:
MARTORELLI, S; ALDA P; MARCOTEGUI, P; MONTES M.; PANEI C.J
Lugar:
Nashville, Tennessee
Reunión:
Conferencia; Aquaculture; 2013
Resumen:
Since some years ago, shrimp and crabs from coastal areas of the Argentine Sea were found with lesions on their shells presumably caused by bacteria. To check this assumption, a study was conducted in the two most abundant estuarine crabs of Argentina, Neohelice granulata (n=36) and Cyrtograpsus angulatus (n=65) collected in Bahía Blanca estuary (38º 44´S, 62º 16´W) . In 5% of the specimens, erosive lesions (up to 5 mm diameter) were observed in ventral and dorsal surfaces of shells (Fig. 1). Scrapings of lesions in saline wet mount, observed under a phase contrast microscopy, showed the presence of protozoans, bacteria, and debris (Fig.2). Some crabs with lesions were fixed in 10% formalin for histological studies. In histological sections of the cuticle very extensive foci were observed. Extended erosions throughout the epi-, exo-, and endocuticle characterized lesions, which was often melanized. Others lesions were scraped in aseptic conditions and the material was spread in plates with TCBS and incubated at room temperature for 24-48 hours. Positive plates showed round, yellow, and bright colonies integrated by Gram-negative bacteria (Fig.3). Although by the form and color of the colonies is not possible the definitive identification, the formation of yellowish colonies on TCBS may be a first indication that the bacteria could belong to Vibrio alginoliticus. DNA extracted from this colonies was amplified by PCR using general primers for 16s rDNA segment and then sequenced. DNA sequences were compared to the ones deposited in GenBank (BLASTN) and the Ribosomal Database Project (RDP). We observed a close relationship with several Vibrio spp. Some of these species have been reported in association with crustacean culture: V. alginolyticus (96% BLASTN), V. furnissii (95% BLASTN), V. vulnificus (96% BLASTN), V. fluvialis (95% BLASTN), V. paccinii (85% RDP), and V. parahaemolyticus (86% RDP). Biochemical reactions will be necessary for the final identification of the specific Vibrio causative agent of this shell disease.