White Plague Epidemic in Caribbean Corals May be Caused by Viruses

White plague is sweeping across the Caribbean, taking casualties wherever it strikes. It's lead to widespread destruction of the corals and, consequently, reefs in the warm waters. Now, scientists have identified one of the possible causes of this growing disease epidemic. It turns out that a group of viruses could be one of the culprits.

White plague is a devastating disease for corals. It causes rapid tissue loss, affects many species of coral and can cause partial or total colony mortality. This can destroy reefs that are already declining due to bleaching and other diseases.

"Twenty years ago you had to look pretty hard to find any occurrences of this disease, and now it's everywhere," said Nitzan Soffer, one of the researchers, in a news release. "It moves fast and can wipe out a small coral colony in a few days. In recent years the white plague has killed 70 to 80 percent of some coral reefs. There are 20 or more unknown pathogens that affect corals and in the past we've too-often overlooked the role of viruses, which sometimes can spread very vast."

Before now, researchers believed that white plague was caused primarily by bacterial pathogens. Yet it turns out that this may not be the case. Researchers have examined white plague a bit more closely and have found viral association with a severe disease epidemic. More specifically, they found small, circular, single-strand DNA (or SCSD) viruses may be the cause of white plague.

The findings are important for better understanding the spread of this disease. As ocean temperatures warm and corals become more stressed, it's crucial to learn how to prevent mass coral die-offs. Yet what is important to note is that viral infection, by itself, doesn't necessarily cause major problems. Instead, a combination of stress factors can cause corals to disappear.

The findings are published in The ISME Journal.