The sad news of the passing of a killer whale at SeaWorld of Texas has of course prompted outrage from animal rights activists who will capitalize on any and all opportunities to condemn the treatment of killer whales under human care.
Unna was a greatly adored adult female orca and beloved member of the SeaWorld family. She had been suffering from what appears to be a resistant strain of Candida, an opportunistic fungal pathogen of both humans and non-human animals. Candida, a yeast, is part of the natural intestinal flora of humans and other animals and has been cultured from the blowholes of wild cetaceans, the oral cavities of people and the esophogeal tissues of rodents, just to name a few examples. Candida is quite the opportunist, as it is commonly found on our skin and any mucosal surface. Worldwide, there are approximately 200 species of Candida, of which 20 are deemed to be medically important and most of these are typically innocuous fungal agents.
Candida albicans, which is commonly reported in humans and non-human animals, is normally considered a commensal organism. Hence, it is usually harmless and only benefits the yeast itself, where and when it occurs on its host species. However, as an opportunistic pathogen it can be dangerous and the causative agent of systemic disease in immunocompromised individuals.
To give you some perspective on the ubiquitous nature of this yeast, Candida albicans is the most common fungal pathogen found in humans. Candida yeast overgrowth in our guts can, and often does, lead to the development of irritating conditions like athletes’ foot and sometimes more serious systemic forms of Candidiasis.
As far as marine mammals are concerned, the prevalence of this mycotic (i.e. fungal) organism in the gut and on other mucosal surfaces is unknown in the wild because we don’t sample every wild pinniped and cetacean seeking to detect Candida. For one, it is normally a commensal organism and not a pathogen and therefore of minor concern. Our awareness of the fungus in captive specimens, including animal ambassadors in marine parks is due to the fact that these animals are commonly monitored and screened for microbial agents that have the potential to cause more serious harm. Fortunately, early detection and treatment of fungal infections is usually succesful.
I’ll share this article from the South African Society for Microbiology with you to inform or remind you that although commensal organisms occasionally become pathogenic in captive cetaceans, the skin and systemic lesions we see in free-ranging marine mammals due largely to the pollution of our oceans is a much greater threat to the worldwide population of orca and other toothed whales than is Candida.
Again, we at ZooNation would like to share our condolences with the entire SeaWorld family concerning the passing of Unna.
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