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DISEASES 

Diseases of corals and other coral reef organisms are expanding rapidly in frequency and effect around the world. The disease situation is unprecedented. Most of the diseases we are now tracking were not around a few years ago, and most do not correlate with obvious known stresses. One thing is certain: the damage they cause is so visible that had these diseases been common before recently, they would have been seen. Yet, the most experienced long-term observers working on these syndromes, who have spent decades searching for unhealthy corals, have rarely if ever seen these diseases before their recent and dramatic spread. The problem is a genuinely new, rapidly increasing cause of coral and reef organism mortality—a major threat to reef health around the world. Corals, sea fans, sponges, algae, sea urchins, fish, turtles and other organisms are being affected. 

Like other emerging diseases affecting human beings, crops, livestock, wild animals and plants, we do not know if these diseases have always been around but are expanding because environmental stress has reduced the ability of organisms to resist them, whether they have recently switched their hosts, whether they have recently developed the capacity for virulence, whether they are newly evolved, or whether pollution and global climate change have accelerated their spread and virulence.  

Most diseases are known only by the characteristic signs of the tissue mortality they produce. In many cases, the pathogen when identified turns out to be a new species. Even when they have been isolated and cultured, the pathogens are often not identified. Most suspect pathogens have not even been successfully cultured, much less isolated or identified. In no case is the reason for their spread adequately understood. Unlike all the other major stresses to reefs, we still know too little about the distribution of diseases, their spread in space and time, how pathogens spread and act and where they originated, to be able to make practical suggestions for policies to reverse them at this time.  

GCRA is involved in field work to identify these diseases and track their distribution and spread. GCRA is also developing a complete photographic and video library of images to allow other researchers to identify diseases, training monitoring teams in identifying and monitoring diseases and providing samples of material to researchers in microbiology, biochemistry, cell biology and other areas.