Humanity Threatens Seals With Bad Bacteria

Between MERS from camels and Ebola from bats (or gorillas), even everyday citizens are learning that deadly diseases jumping from animal to human - called zoonosis - is a lot more common than previously thought. Now a new study has revealed that just the reverse can happen, with a dangerous human pathogen somehow finding its way into gray seal colonies.

That's at least according to a study recently published in the journal Molecular Ecology, which details how gray seals breeding on Scotland's Isle of May were turning up sick and even dead from Campylobacter infections.

Being a bacteria that triggers food borne illnesses in humans, it had long been thought that Campylobacter would never affect ocean life. Researchers had assumed that, like evil cannot cross water, the bacteria simply was unfit for aquatic travel, only jumping between humans and livestock for as long as health experts have known about it.

However, during autumn of 2011, a team of investigators found the pathogen in nearly half the samples taken from 100 live and 50 recently deceased seal pups.

As is common with many mammals, not all newborn seals are expected to survive their first few months, even if pups born on land like the Isle of May have better survival rates than pups born on ice, according to the IUCN.

Still, what was surprising about these samples was that the dead pups harboring Campylobacter had signs of intestinal inflammation - the same symptom the infection causes in humans.

"Campylobacter has been previously detected in seals at very, very low levels," Johanna Baily explained in a statement. But "the prevalence we found in gray seal pups was absolutely shocking."

Dale Griffin, a public health microbiologist at the US Geological Survey, who was not involved in the study, added that it still remains completely unclear how this bacteria is reaching the seals, but he argues that the case for human-to-animal zoonosis is not concrete just yet.

"Are the seals swimming in areas impacted by sewage or wastewater? Or is it that [another] carrier, such as a wild bird, is bringing the infection back to the island?" he asked via the AAAS.

However, according to Baily and her colleagues, what is important is that this case raises awareness: our pathogens can impact other species just as much as theirs impact us. Whether we should take action to fight these diseases in other animals, however, remains a topic for debate.

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