Abstract
Helicobacter species isolated from the stomachs of humans and animals have been the focus of considerable research due to their association with gastro-duodenal disease.4,5 In humans, Helicobacter pylori causes chronic gastritis, peptic ulcers and is linked to gastric adenocarcinoma and gastric mucosa-associated lymphoma.
It has been reported that gastric ulcers occur in wild and captive dolphins.1,7-9 A number of cases have been associated with parasitic infections.1-3,7 However, for many decades cases of non-parasitic gastric ulcers with no clearly defined etiology have been noted in wild and collection animals.3,6,9
The goal of this research was to determine whether Helicobacter spp. could be isolated from the stomach of stranded dolphins. We assessed the glandular stomach of seven stranded white-sided dolphins, Lagenorhynchus acutus, and one common dolphin, Delphinus delphis. The animals were made available through the New England Aquarium/Fleet Bank Marine Animal Rescue Team. Novel Helicobacter isolates were identified by PCR and culture in the gastric mucosa of six of the eight dolphins. By 16S rRNA analysis it was determined that these isolates were a novel Helicobacter sp. closely related to other gastric Helicobacter. Spiral organisms were detected by Warthin Starry stain. Histologic sections were evaluated in two infected animals. There was multifocal lymphoplasmacytic gastritis and mucous epithelial hyperplasia. The lesions parallel those observed in Helicobacter pylori-infected humans. These findings suggests that a novel Helicobacter may be playing a role in the etiopathogenesis of gastritis and gastric ulcers in dolphins.
Acknowledgments
We thank the New England Aquarium for providing us with the stranded animals and helping with the sample collection. We also thank Ms. Belinda Rubinstein and Mr.Greg Early from the New England Aquarium, Dr. Larry Dunn and Ms. Gayle Sirpenski from the Mystic Aquarium, the National Aquarium in Baltimore, Dr. Ruth Ewing and Dr. Julia Zaias from the National Marine Fisheries Service, South East Fisheries Science Center Miami Laboratory, Dr. Charles Potter from the Smithsonian and National Marine Fisheries for their assistance, expertise and support.
References
1. Abollo E. 1998. Long-term recording of gastric ulcers in cetaceans stranded in the Galician (NW Spain) coast. Diseases of Aquatic Organisms 32:71-73.
2. Beverley-Burton M. 1978. Helminths of the alimentary tract from a stranded herd of the Atlantic white-sided dolphin, Lagenorhynchus acutus. J. Fish. Res. Board Can. 35:1356-1359.
3. Coffey D. 1977. Dolphins, whales and porpoises and encyclopedia of sea mammals. MacMillan Publishing Co. Inc. New York. p. 39.
4. Fox JG. 1997. The expanding genus of Helicobacter: Pathogenic and zoonotic potential. Seminars in Gastrointestinal Disease 3:124-141.
5. Fox JG. 1998. Helicobacter species and in vivo models of gastrointestinal cancer. Aliment Pharmacol Ther. 12:37-60.
6. Geraci JR, K Gerstmann. 1966. Relationship of dietary histamine to gastric ulcers in the dolphin. J. Am.Vet. Med. Assoc. 149(7):884-890.
7. Herreras MV, Kaarstad SE, Balbuerna JA, CC Kinze, 1997. Helminth parasites of the digestive tract of the harbor porpoise Phocoena phocoena in Danish waters: a comparative geographical analysis. Diseases of Aquatic Organisms 28:163-167.
8. Leatherwood S, R Reeves. 1990. The Bottlenose dolphin. Academic press, p. 176.
9. Sweeney JC, SH Ridgway. 1975. Common diseases of small cetaceans. J. Am. Vet. Med. Assoc. 167:533-540.