Evidence:

Although Mycobacterium has been positively identified in several animal species, it has only rarely been reported in marine mammals. However, as recently as 1981 a total of 16 seals were captured from the Archipelago of Recherche in southern Western Australia (Forshaw & Phelps 1991).

•8 New Zealand fur seals
•3 Australian sea lions
•1 Australian fur seal imported from another marine park
•1 Australian sea lion imported from a veterinary clinic
•3 sea lions captured near the marine park

Of the sixteen, six had evidence of mycobacteria upon analyses. It was first assumed to be a result of M. bovis but genetic analysis revealed significant differences. Eventually, it was said to be M. tuberculosis, the same strain found in humans (Forshaw 1991). Although according to Cousins (1990) it may in fact be a unique species altogether. The majority of the infected seals showed signs of pulmonary lesions which would suggest that inhalation was the primary means of infection. It is believed that at least one of the seals must have been infected prior to capture for the following reasons:

• All six seals had the same strain
• Since tuberculosis is not considered common in pinnipeds it is likely that the disease spread in the confines of the marine park.
• No other animals or staff within the park was infected with tuberculosis at the time of diagnosis.

This is worth noting for several reasons. Firstly, and most immediately, Cousins, as cited by Forshaw (1991), notes the possible danger to both humans and seal populations alike. With the emergence of multi-drug resistant strains of tuberculosis across the globe, TB is unfortunately a modern threat (http://www.lungusa.org/site/pp.asp?c=dvLUK9O0E&b=22542). It is therefore important to be aware of any and all possible vectors that could lead to transmission. Seals are especially worrisome because unlike most cases they appear to carry, at least in this instance, the human strain of the disease, whereas, most animals play host to M. bovis or even M. avium.

Secondly, the identification of M tuberculosis in pinnipeds supports the theory that seal hunting could have resulted in the introduction of TB in Alaskan Eskimo populations prior to European contact. As stated earlier, the butchering of the animal, raw food consumption, and even the reuse of the skin and intestines to make clothing, shelter, etc. can all lead to the transmission of the disease (Keenleyside 1998).