Human Pathogens in Marine Mammal Meat – A Northern Perspective

Abstract

Only a few countries worldwide hunt seals and whales commercially. In Norway, hooded and harp seals and minke whales are commercially harvested, and coastal seals (harbour and grey seals) are hunted as game. Marine mammal meat is sold to the public and thus included in general microbiological meat control regulations. Slaughtering and dressing of marine mammals are performed in the open air on deck, and many factors on board sealing or whaling vessels may affect meat quality, such as the ice used for cooling whale meat and the seawater used for cleaning, storage of whale meat in the open air until ambient temperature is reached, and the hygienic conditions of equipment, decks, and other surfaces. Based on existing reports, it appears that meat of seal and whale does not usually represent a microbiological hazard to consumers in Norway, because human disease has not been associated with consumption of such foods. However, as hygienic control on marine mammal meat is ad hoc, mainly based on spot-testing, and addresses very few human pathogens, this conclusion may be premature. Additionally, few data from surveys or systematic quality control screenings have been published. This review examines the occurrence of potential human pathogens in marine mammals, as well as critical points for contamination of meat during the slaughter, dressing, cooling, storage and processing of meat. Some zoonotic agents are of particular relevance as foodborne pathogens, such as Trichinella spp., Toxoplasma gondii, Salmonella and Leptospira spp. In addition, Mycoplasma spp. parapoxvirus and Mycobacterium spp. constitute occupational risks during handling of marine mammals and marine mammal products. Adequate training in hygienic procedures is necessary to minimize the risk of contamination on board, and acquiring further data is essential for obtaining a realistic assessment of the microbiological risk to humans from consuming marine mammal meat.

The Seal Louse (Echinophthirius horridus) in the Dutch Wadden Sea: Investigation of Vector-Borne Pathogens and Morphological Adaptations

“…Mycoplasma sp. was also molecularly identi ed in collected seal lice specimens and in contrast to A. phagocytophilum there are previous reports on occurrence of mycoplasmal infection in pinnipeds [44,45,46,47,48,49]. Thus, Mycoplasma spp.…”

Prevalence of antibodies against Brucella spp. in West Greenland polar bears (Ursus maritimus) and East Greenland muskoxen (Ovibos moschatus)

“…polar bears and seals), comprises a unique opportunity to study the occurrence of zoonotic diseases in a One Health perspective while tying together human and ecological and wildlife health. Brucellosis is in general a major public health concern worldwide (Ross et al 1996;Tryland et al 2013). The presence of antibodies against Brucella spp.…”

“…The Arctic ecosystem is subject to several interacting anthropogenic stressors that cause cumulative stress in humans and wildlife, which may in turn lead to increased susceptibility to zoonotic infections (Atwood et al 2017;Jenssen et al 2015;Greer et al 2008;Hueffer et al 2011;Sonne 2010). In some human populations in the Arctic, it is common to consume raw or insufficiently heat-treated wildlife and game meat (Tryland et al 2013). The importance of heat-treatment is exemplified by studies of toxoplasmosis in North America, where 80% of examined humans were seropositive in an Inuit community with dietary preference for raw meat, as opposed to 10% seropositivity within a local Cree population having dietary preference for cooked foods (Lévesque et al 2007;Messier et al 2009).…”

“…Marine mammals including polar bears, are an important food source for people in the Arctic, yet the burden of zoonotic pathogens in these species remains largely unknown in most Arctic regions. While human cases of trichinosis and digital mycoplasmosis ("seal-finger") are typically reported (Rodahl 1952;Tryland et al 2013), the pathogen-spectrum has rarely been addressed by systematic studies. In addition to marine mammals, muskoxen are also an important food resource in some parts of the Arctic.…”

“…In addition to dietary exposure, Arctic hunters are in frequent physical contact with raw tissues and fluids of hunted wildlife, most often lacking any preventive measures against transmission of zoonotic pathogens. Information about the occurrence of wildlife transmitted zoonotic diseases in the Arctic parts of Europe is generally limited (Jenkins et al 2013;Tryland et al 2013), while it has been studied more intensively in Arctic Canada (Campagna et al 2011;Goyette et al 2014;Lévesque et al 2007;Messier et al 2012;Sampasa-Kanyinga et al 2013).…”