Ocorrência de patógenos em Anomalocardia brasiliana (Gmelin, 1791) (Bivalvia: Veneridae), do estuário do Rio Pacoti/CE

Abstract

In Ceará State, the bivalve Anomalocardia brasiliana, has considerable socioeconomic importance for the communities living around the estuaries. However, studies of the health of this species in this region are scarce_ This study aimed to investigate the occurrence of pathogens in Anomalocardia brasiliana in a natural bank at Pacoti River Estuary, Ceara. Samples of live animals (N = 360) were collected for pathologic analysis, from february 2008 to january 2009. The animals were opened for the removal of soft tissues and a cross section of the body, containing mantle, gonad, gills and digestive gland, was made. After histological processing, 5 pm cuts were made in a manual microtome and histological sections were stained with Harris's hematoxylin and eosin. The diagnosis of the pathogens was done by optical microscopy. The results revealed rickettsia-like bacterial colonies, digenetic trematodes of the genus Bucephalus, cestodes of the genus Tylocephalum and unidentified metazoan. The rickettsia-like bacterial colonies and larvae of cestodes showed overall prevalence rates of 7.2% and 35.5%, respectively. The monthly prevalence of infected animals by Bucephalus sp. ranged from 16.7% (march, may, june) to 56.7% (october). The infected animals had probably changed their reproductive cycle, because most of them showed partial or complete castration of the gonad. The results indicate that the population of A. brasiliana, is highly affected by Bucephalus sp., therefore the natural bank studied must be continually monitored, as this parasite causes host castration, preventing gametogenesis and consequently the reproduction of this mollusk.