Subcutaneous Steatitis Due to Brucella pinnipedia in a Hunter Harvested Narwhal
IAAAM Archive
Stephen Raverty1; Ole Nielsen2; Wei Ling Yu3
1Health Center, Abbotsford, BC, Canada; 2Central & Arctic Region, Fisheries and Oceans Canada, Winnipeg, MB, Canada; 3Animal Disease Research Institute, Canadian Food Inspection Agency, Ottawa, ON, Canada


The beluga whales and narwhals are an integral part of the natural history of the Inuvit and federal legislation affords a subsistence harvest of these marine mammals. Over the course of the last decade, opportunistic tissue and blood samples obtained in the Canadian arctic has provided insights into the health status of these animals.

On August 2004, a juvenile narwhal was shot near Grise Fiord, Nunavit, Canada (AR.GR.MM.04 #001). During the flensing of the carcass, at an unspecified anatomic site, focally extensive yellow discoloration involving the entire depth of the blubber was noted and centrally, there was a 5x10 cm oblong cavitation, which contained numerous variably sized, round to irregularly, smooth facetted firm mineral deposits that were peripherally bound by a thick fibrous connective capsule that merged abruptly with adjoining stroma.

Histopathology confirmed the grossly noted dystrophic mineral deposition and multifocal granulomatous infiltrate within dermal with no discernible pathogens. Polymerase chain reaction of frozen blubber from the affected area was positive with universal Brucella spp primers. A portion of skin was forwarded to the Animal Disease Research Institute and DNA sequencing and the isolate was identified as Brucella pinnipediae.

Detection of these bacteria may have profound implications for the health status of this animal, as well as potential zoonotic concern for hunters and individuals harvesting and preparing the blubber for muktuk. Based on previous investigations with beluga whales, polymerase chain reaction, sero-, and culture positive animals have presented with peri-ovarian and epididymal cavitating granulomas due to brucellosis. In a survey from 1989-2003, cysts were identified in 45/139 or 32% in hunter killed beluga and narwhal and from 1984 to 1996, 5 of 77 narwhal (6.5%) and 28 of 488 (5.7%) harvested beluga whales were seropositive for Brucella spp.

Although sub-blubber abscessation has previously been reported in a stranded marine mammal, cutaneous brucellosis is a relatively uncommon clinical manifestation in other (terrestrial) species. In humans, transient erythema nodosum (deep dermal nodules on the legs), petechiae (trunk and proximal extremities), (leukocytoclastic) vasculitis, papules, rashes and hypersensitivity reactions (contact urticaria) have been reported in 6-15% of cases. Infections were attributed either to hematogenous dissemination and localization to the dermis or direct contact and penetration via an abrasion or wound. In horses, fistulous withers is associated with a bursitis rather than dermatitis.

Human infections have been reported through handling of contagious material suggests that care should be exercised when harvesting skin and blubber for the preparation of muktuk and appropriate hand washing and possible use of protective gloves is recommended.

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Stephen A. Raverty

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