Harbor seal (photo: Joe Gaydos)
News from the SeaDoc Society, a program of the school's Wildlife Health Center.
While most people think of brucellosis as a disease that hits bison, elk and cattle - especially around the Greater Yellowstone Area - harbor seals and other marine mammals also can be infected with marine varieties of the bacterium Brucella.
Brucella pinnipedialisis is obviously not impacting the Salish Sea's harbor seal population (one of the densest in the world), but it can infect people, domestic animals and endangered species like southern resident killer whales. For those reasons, it is important for us to understand how this disease is transmitted and where it might pose a risk to people or other animals.
Joe Gaydos at SeaDoc, Dyanna Lambourn of the Washington Department of Fish and Wildlife, and other collaborators recently published a paper in the Journal of Wildlife Diseases that unravels the mystery of how this pathogen is transmitted in seals. As it turns out, harbor seals are not exposed to the disease until they are weaned and start eating fish and invertebrates. Once infected, they can shed the bacterium in their feces and in their salivary glands. This means that biologists are most at risk when working with weaned pups and yearling seals.
The next step in protecting human health is to determine which fish or invertebrates might be involved in transmitting the disease to seals. Interestingly, they also found a higher prevalence of the disease in South Puget Sound where harbor seals have a higher burden of organic pollutants, suggesting that their high toxin levels could be suppressing their immune system and decreasing their resistance to the disease.
Interested in learning more? Download a copy of the paper here
Click here to read the November 2013 Update from the SeaDoc Society.
Director, SeaDoc Society