Are probiotics a key to slow spread of Florida's devastating coral disease?

Stony Coral Tissue Loss Disease - white-plague disease coral disease FWC - stony coral tissue loss disease — Coral tissue loss disease. From a 2017 Florida Fish & Wildlife Conservation Commission video.

The most extensive coral disease ever is still spreading and could cause several species to go locally extinct in Florida, but scientists are studying how probiotics could help slow the spread of stony coral tissue loss disease (sctld).

WMNF spoke with Blake Ushijima, a post-doctoral researcher at the Smithsonian Marine Station in Fort Pierce on Florida’s east coast.

“This particular disease, they believe it started around the end of 2014 in the Miami area. Since then, it’s actually spread as far north as it can possibly spread. And is currently almost halfway to Key West. They’ve also reported in the U.S. Virgin Islands, Jamaica, and different parts of Mexico.

“The terrifying thing about this disease is, one, that — even since starting in 2014 — it’s still spreading and still present in areas that it’s affected. Also, it seems to be affecting at least 20 different species of coral, which is quite concerning.

“These corals, as it said in the name, they get, what we call, tissue-loss lesions in that the coral animal, itself, is actually dying. So this is a little different than — most people hear about bleaching in the news — which is the loss of the algae that lives within corals. This is actually the coral animal dying. So the white you sometimes see in the field is actually just the exposed skeleton.

“So far, people have narrowed it down. It is a transmissible disease. So, it is caused by some kind of infectious agent. And currently we believe bacteria are very important for this disease progression. We’re still unclear if it’s actually bacterial or could be a viral component that’s initiating this disease. However, because it seems that bacteria are important for lesion progression, you can stop it with things like antibiotics.”

SK: I’ve talked to a researcher who is having success spreading antibiotics on certain corals, and it’s stopping the spread there. But you’re looking at actually how probiotics might impact this coral disease. What does that mean, to use probiotics and what have you found?

“Probiotics are just beneficial microorganisms. The main difference between probiotics and antibiotics — it’s the same thing with humans. Antibiotics, when you get sick, you’ll treat the pathogen directly. But, you actually have to keep constantly taking doses of antibiotics. But also, with the spread of antibiotic-resistant bacteria, you want to limit the amount of antibiotics used. Same goes for the ocean. If there is an alternative, we do want to try an alternative. However, it is seen to be treating the lesion directly.

“The major drawback is, these researchers who are using antibiotics, they’re spending a tremendous amount of time in the field. I mean, they’re out there diving, dealing with the currents. They’re carefully applying these treatments, the individual colonies at a time. There has been a lot of corals that have been lost from Florida. But there’s still thousands out there that still need to be treated. So, it’s a tremendous amount of work.

“However, after the treatment’s over, it’s not getting rid of the actual disease, itself, in the environment. So, these corals can still get reinfected.

The thing about probiotics — and it’s been used in a lot of other systems — is that these beneficial microorganisms can actually colonize the host and provide some kind of lasting protection. So it’s more of a long-term protection, instead of direct treatment of disease.”

Listen to much more of the interview here: