White band disease

White band disease causes the affected coral tissue to spin off the skeleton in a white uniform band for which the disease was given its name. The band, which can range from a few millimeters to wide, typically works its way from the base of the coral colony up to the coral branch tips. The band progresses up the coral branch at an approximate rate of 5 millimeters per day, causing tissue loss as it works its way to the branch tips. There are two variants of white band disease, type I and type II. Type II of white band disease can be mistaken for coral bleaching. By examining the remaining living coral tissue for bleaching, one can delineate which type of the disease affects a given coral. ==Pathogen==

No known pathogen has been isolated (it has only been attempted for type II) for white band disease, although there is a shift of bacterial composition in the surface layer where the band eats away as the coral tissue. The bacteria shifts from a dominant pseudomonad population to an increasingly dominant Vibrio carchariae population. The study focuses on coral cells and the corals' gene responses, highlighting the importance of internal coral mechanisms rather than external factors alone. ==Impact and range==

Since white band disease was first reported in the 1970s, the disease has led to the devastation of approximately 95% of the elkhorn and staghorn corals in the Caribbean region. Elkhorn and staghorn corals are two of the major reef-building corals, the foundation on which the rest of the coral reef is formed. ==Transmission==

White band disease is highly contagious through direct contact between diseased and healthy coral tissue. C. abbreviata, a species native to the region where Elkhorn and Staghorn corals are found, is able to act as a "reservoir" for white band disease, meaning that it is able to retain the disease pathogen for at least two weeks. Insights into the nature of white band disease transmission provide understanding of how the disease might be managed and controlled to prevent major losses in coral. The study suggests that early detection at the site of infection is crucial for controlling disease spread between healthy and infected corals A 2025 study by researchers at Northeastern University tested whether treating healthy coral fragments with antibiotics could prevent white band disease. The study found that pretreated corals were much less likely to become infected. Antibiotic pretreatment reduced infection rates by about 30 percentage points compared to untreated fragments. ==Effects of climate change==

White band disease prevalence in the Caribbean varies seasonally. Anthropogenic climate change is negatively impacting the world's corals and coral reef ecosystems. Over the next few decades as climate change continues, oceanic warming and acidification will accelerate and further damage the fragile reef ecosystems. Prediction of the impacts of future climate change on coral reefs can be difficult given the uncertainty in certain involved socioeconomic factors (i.e. political response, future technology, changes in human behavior, the Earth's climate system, and the realtime effects on coral reefs). Despite these uncertainties, humans could see the extinction of the coral reef ecosystem by the end of the 21st century if actions are not taken to protect them. According to forecast models of increasing oceanic temperature, mass mortality events will likely occur as early as the summer of 2030 and continue to occur on an annual basis. ==Environmental Factors==

The expansion of the human population and development in coastal areas leads to an increase in pollution, which is threatening coral reef health. Nutrient pollution, such as fertilizer runoff or sewage, can influence coral disease, weakening coral immune responses. Fertilizer runoff or sewage contains high levels of nutrients and pathogens, which harm coral reefs and other marine life. Studies on several Caribbean coral species, including Siderastrea siderea, Orbicella annularis, and O. franksi, have found that nutrient enrichment increases disease prevalence and disease progression. These findings definitely highlight how nutrient pollution may increase the severity of the coral epidemic. Studies have shown that extreme weather changes, such as hurricanes, may also contribute to the increase of white band disease. Following Hurricane Dean, a study was conducted in the Banco Chinchorro Biosphere Reserve in Mexico to investigate the relationship between coral disease and the hurricane. The study found that physical damage from storms can increase the vulnerability of corals to disease. These results highlight the interaction between storms and coral disease in reef ecosystems. ==See also==