Abstract
The chambered nautilus (Nautilus pompilius), a cephalopod species from the deep water of the Indo-pacific areas,1 is not uncommon in North American aquariums and zoos. Little is known about viral and bacterial diseases of nautilus. The black shell syndrome is the most common problem in captivity7 and has an unknown and probably multifactorial etiology. A retrospective study of 55 chambered nautili (37 males, 16 females, and two of unknown sex) that died at National Zoological Park was performed. The captive life span was short, less than 4 yr, and weight ranged from 244.7–782.6 g for males and 230.2–590 g for females. The most common gross findings were black shell syndrome in 37/55, 10/55 with digestive gland adenitis, 9/55 with cloudy coelomic fluid, 3/55 with esophageal dilation, 3/55 with ingestion of a foreign body and 2/55 with head deformation. Culture of fluids or tissues were processed in 58% (32/55) of the animals. Vibrio spp. was the most common organism identified (13/32), similar to findings in cuttlefish6 and marine fishes2-4,8. Species included V. alginolyticus (5/13) and V. vulnificus (2/13). Vibrio has been associated with necrotizing inflammation in fishes2-4,8, lobster2, and cuttlefishes6. V. alginolyticus is also a significant pathogen in marine crustaceans.2 Several other bacterial genera, mostly gram-negative organisms, also were isolated. Multisystemic hemocytic inflammation was seen in 44/55 animals. The gills, heart, intestine, renal appendage, digestive gland, and integument were the most commonly affected organs and organ system. Renal mineralization was observed in 20 nautili (36.3%), of which 19 cases were associated with sepsis. Protozoa were the most common parasites (4/6) and were associated with digestive gland adenitis. The renal mineralization observed in 36.3% of the cases could be a consequence of sepsis, could predispose to sepsis, and/or could be related to water quality or nutrition. The nautilus immune system can be compromised by poor water quality, overcrowding, and/or increased bacterial load on the aquatic system.5 Further studies should be done to determine the cause of renal mineralization and identify the parasites of these nautili.
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