Corals have been fighting a losing battle for years against a new enemy – disease. There are about 30 known coral diseases, all of which have been discovered in the past three decades. Very little is known about these diseases other than they are caused by a variety of agents like bacteria, fungi, algae and worms. Even less is known about the coral’s natural abilities to fight them off.

<img src=“http://www.reef.crc.org.au/discover/coralreefs/images/hf01055-230.jpg” style=“Float:right; margin:0 0 5px 10px” width=200 alt=""/>In the Caribbean, 80% of corals have been lost to disease in the past 20 years. This loss has made the once ecologically dominant staghorn corals (Acropora spp.) critically endangered by IUCN standards. They are particularly susceptible to one disease, known as White Band Disease (WBD) due to its characteristic coloration, which is host-specific to their genus.

New research has started to unravel some of the mystery of coral infection and resistance. A study, published in PLoS ONE, has found that staghorn corals are able to naturally resist disease – at least 6% of the taghorn coral genotypes are resistant to WBD. This is the first evidence that scleractinian corals have natural resistance to disease – which is good news for coral reefs.

This new discovery might help scientists better understand the mechanisms of disease resistance in corals, and if there is anything we can do to help. It also may help unlock the keys as to how the corals are infected and killed by the pathogens, which is poorly understood.

While more research is needed to determine the factors underlying natural disease resistance, this study gives a blueprint for simple methods to determine resistance and a way of conducting further research on disease resistance. Identifying resistant species is useful from a conservation standpoint as well, as it gives targets for coral farming and local replanting to aid in restoration attempts.