


sea horse in coral
Seahorses, such as the pygmy seahorse above, often live in or around coral, which serves as a hiding place and source of food.

Corals face a number of threats, these diseases included, what's more climate change is thought to act as a catalyst, as oceans become warmer and corals are pushed to live in more extreme temperatures. Not only could the immunity of the corals be compromised due to extreme living conditions, but heat can also provide more favourable conditions for bacteria to grow and thrive - and these diseases are understood to be caused by bacteria, fungi and/or viruses.

The exact pathogenic microorganisms causing WBD have not been identified, and as lead researcher, Dr Michael Sweet explains, this problem has been faced by researchers for some 40 years. Sweet's team took a different approach to that taken in previous studies, and decided to take already diseased coral and use antibiotics to cure them (as opposed to infecting healthy coral with the disease and examining the implications of the infection). Using a process of elimination he was able to understand which microbes were to blame, at least in this Caribbean coral under examination. The study involved 4 different antibiotics, and 2 of these were found to successfully treat the diseased corals. 'The disease causing microbes we were trying to knock out, were present in the diseased coral and the antibiotic treatments which didn't cure it, but it would not be present in the healthy coral, nor the two antibiotics which cured it,' says Sweet. Genius! And the findings? In this instance, three types of bacteria were found to be at the root of the WBD, as well as a microorganism called ciliate; in particular a species called Philaster lucinda.

Parallels to the human body

Interestingly, so many parallels can be drawn from this research and the research conducted on gut microbiota and immunity in us humans. Sweet explains that the bacteria involved in WBD works by hindering the immune system of the coral; reducing its efficacy by factors such as a reduction of the number of defensive stinging cells. After this initial weakening of the immune system, the ciliates attack the tissue of the coral. 'It's a bit like when you have a cold and you become more vulnerable to other diseases in the surrounding environment', he says.

Antibiotic Resistance

The most fascinating part of all? Although the antibiotics were able to cure the WBD in these corals, Sweet and his team do not advocate the use of antibiotics for corals, stating that this could lead to antibiotic-resistant microbes and superbugs in the future. I cannot stress enough, the relevance and importance of this statement! We posted just this morning on our Facebook page about the overprescription of antibiotics, and the danger of antibiotic resistance. (If you're interested please do give our page a like and join the discussion!) The World Health Organisation wants this high up on the agenda[1], and it is quite rightly, a topic seeing more and more focus at the moment. Perhaps this is why Sweet suggested developing a probiotic as opposed to an antibiotic, to support the coral's immune system and 'let the coral fight off the pathogen itself.' Fantastic.

Antibiotics vs probiotics

When it comes to human health, for the moment at least, probiotics should not be substituted for antibiotics. Nutritional therapist Jo Saunders wrote an excellent piece on this recently, see her blogpost 'Probiotics Vs Antibiotics? You're asking the wrong question'.

So can probiotics cure coral? The research is yet to be carried out, but we certainly think the scientific theory behind this is sound.




Sweet MJ, Croquer A,Bythell JC. 2014 Experimental antibiotic treatment identifies potential pathogens of white band disease in the endangered Caribbean coral Acropora cervicornis. Proc. R. Soc. B 20140094.

Image of seahorse in coral:

Cartoon 'Probiotics Vs Antibiotics':

Write a comment