Bacterial disease of cultured giant darn Tridacna gigas larvae

Abstract

The role of bacteria in mortality of the planktonic larval stage of cultured giant clams Tridacna gigas was examined. Addltion of the antibiotic chlorarnphenicol at 5 ppm reduced larval mortality and confirmed the involvement of bacteria in disease prior to settlement. Syn~ptoms of bacterial disease were usually rapid and profuse bacterial growth on and in larval clams and disintegration of most tissues withln 48 h. Results of tests in which larvae were exposed to 10' bacteria ml-' suggested that bacteria belonging to the genera Vibrio and Aeromonas are often pathogenic to larval clams and that those in other genera are less frequently pathogenic. Bacterial isolates with characteristics most s~milar to V. metschnikovii , V. alginolyticus, V. harveyi, V . splendids 1, V. campbelli, V. orientalis and Photobacterium (Vibrio) damsela caused 100 % mortality. Mortality varied with different isolates of V. metschnjkovii , V. alginolyticus, V. harveyi and P. damsela, suggesting isolatespecific pathogenicity. The results are discussed in terms of current knowledge of bacterial diseases of cultured marine invertebrates.

Pathogenic bacteria isolated from disease outbreaks in shellfish hatcheries. First description of Vibrio neptunius as an oyster pathogen

“…During settlement and metamorphosis, the most critical stages in larval development, larvae begin a life associated with substrate in high densities and come into contact with the resident microbiota and, hence, with putative pathogens (Sutton & Garrick 1993). All these factors can facilitate the transmission or appearance of diseases.…”

Isolation and characterization of a virulent Vibrio sp. bacterium from clams (Meretrix meretrix) with mass mortality

“…V. furnissii is a Gram-negative bacterium which has been associated with acute diarrhoeal illness after consumption of contaminated seafood (Brenner et al, 1983), and it has been reported to be associated with the disease of clam (Wang et al, 1992). V. fluvialis, V. cincinnatiensis, V. mimicus, and V. metschnikovii have also been associated with bivalves (Montilla et al, 1994;Maugeri et al, 2000;Cavallo and Stabili, 2002;Sutton and Garrick, 1993). Although most of the species within the Cholerae clade can cause diarrhea (Sawabe et al, 2007), there are limited reports on the pathogenicity of this clade to bivalve-related species.…”

Vibrios as causal agents of zoonoses

“…Tridacna gigas with infection leading to general disintegration of the tissues and 437 total mortality after exposure to 10 7 bacteria ml -1 (Sutton and Garrick, 1993). The 438 organism has been recovered from raw fish and shellfish in markets and shops, 439…”