Parasites of economically important bivalves from the southern coast of Bahia State, Brazil

Abstract

This study investigated the parasites of three commercially important bivalve species (Crassostrea rhizophorae, Mytella guyanensis and Lucina pectinata) from the southern coast of Bahia, Brazil. A total of 540 specimens were collected in August 2009 and February 2010, at three localities. The bivalve specimens were measured on their longest axis, opened, and macroscopically examined for the presence of parasites or signs of disease. They were then fixed in Davidson' solution and subjected to routine histological processing, with paraffin embedding and H&E staining; next, the specimens were examined under a light microscope. . Nematopsis sp. ocorreu em alta prevalência, porém, aparentemente, não causou danos aos bivalves. Bucephalus sp. causou destruição de tecidos, com castração, mas foi pouco prevalente. Os demais parasitos ocorreram em baixa prevalência e intensidade de infecção e sem causar danos.

Parasites in the mangrove oyster Crassostrea rhizophorae cultivated in the estuary of the Graciosa River in Taperoá, Bahia

“…However, the gill functions of host animals, which are severely infected by these gregarines, may be compromised (CARBALLAL et al, 2001;ESTEPA, 2006). Regarding this parasite, as was reported by Zeidan et al (2012), the present study found a range of one to three oocysts per phagocyte in most cases. Pinto & Boehs (2008) studied Nematopsis sp.…”

“…has frequently been recorded in C. rhizophorae. Similarly to polychaetes, this parasite has been reported not to cause significant damage to its host's health (NASCIMENTO et al, 1986;BOWER et al, 1994;AZEVEDO & MATOS, 1999;WINSTEAD et al, 2004;CREMONTE et al, 2005;SABRY et al, 2007;ZEIDAN et al, 2012). However, the gill functions of host animals, which are severely infected by these gregarines, may be compromised (CARBALLAL et al, 2001;ESTEPA, 2006).…”

“…In Crassostrea virginica (WINSTEAD et al, 2004), C. gigas (PONTINHA, 2009) and C. rhizophorae (ZEIDAN et al, 2012;BRANDÃO et al, 2013), it is often found in the digestive gland. However, in C. rhizophorae, this parasite was only observed at low prevalence and infection intensity in the digestive tubules, without causing significant damage to the host (BOWER et al, 1994;VILLALBA et al, 1997;WINSTEAD et al, 2004;SILVA & VILLALBA, 2004;PONTINHA, 2009;ZEIDAN et al, 2012;BRANDÃO et al, 2013). The opportunistic behavior of this ciliate contributes towards its greater frequency of occurrence in bivalves, especially those that show physiological stress caused by other pathogens (RUSSEL, 1967;LAUCKNER, 1983).…”

“…and RLOs at lower intensity. Zeidan et al (2012) and Brandão et al (2013) also studied C. rhizophorae on the coast of Bahia and observed Urastoma sp. in the gills and mantle, with a range from one to three histological specimens per section, and no histological change was observed.…”

“…These parasites have been more frequently referred to as guests that do not cause any damage to their hosts (LAUCKNER, 1983;BOWER et al, 1994;BRUN et al, 1999). However, at high infection levels, they can be considered to be pathogenic and cause macroscopic lesions, highlighted by localized white patches and microscopic changes that are characterized by disorganization in the branchial filaments, hypertrophy of the epithelial cells and hemocytic infiltration, with evidence of reduced filtration capacity (ZEIDAN et al, 2012).…”