Salmonellosis in the marine environment. A review and commentary

Marine cetaceans (whales and dolphins), pinnipeds (seals and sea lions), reptiles (turtles and crocodyles), fish and shellfish, and fish-eating birds have been found to harbor salmonellae. In some of these animals, clinical salmonellosis has been demonstrated, but in many cases, the isolated salmonellae may have been an opportunistic pathogen with the illness or death of the host due to other causes. On the basis of the few reports in the literature, marine reptiles (turtles and crocodyles), fish, and shellfish appear to be passive carriers of salmonellae and demonstrate no clinical disease. All of these animals constitute a potential source of salmonellosis in man and his domestic animals. The role of wild and domestic terrestrial animals and fresh water aquatic animals in the transmission of salmonellosis to man has been recognized for many years. The situation with regard to the marine (saltwater) animals has never been adequately investigated or reported. In the past, much reliance has been placed on the ability of saline waters to inhibit or destroy human pathogens, including the salmonellae. Whether this effect is chemical, physical or biological has been studied since the late nineteenth century, and the investigators have found a number of factors affecting both the inhibition and stimulation of growth of salmonellae in saline waters. Salmonellae have been isolated from or found to survive in seawater with salinities as high as 3.5 percent. Marine animals in many parts of the world have been found harboring salmonellae.