White band disease
Encyclopedia
White band disease is characterized by complete coral
tissue degradation of Caribbean
acroporid corals. Two species are affected, Acropora palmata and A. cervicornis (Gladfelter, 1982). The disease exhibits a sharp demarcation between apparently healthy coral tissue and exposed coral skeleton. These signs are identical to White plague
, except that white band is acroporid specific, whereas white plague has not been found on acroporids. Tissue loss usually proceeds from the base of the colony branch to the tip, although it can begin in the middle of a branch in A. cervicornis.
There are two distinct disease types that differ in the pattern of tissue loss. White band Type I exhibits tissue degradation associated with a line that migrates across the coral colony. There is no obvious microbial band, although the freshly exposed coral skeleton appears band like. Tissue lysis
is always associated with the moving front (which differentiates Type I from Type II). The rate of tissue loss varies from mm to cm/day (Peters et al., 1983). White band Type II also exhibits tissue degradation as a band moves across a coral colony, however in this case the moving front may, at times, have a bleached zone that catches up to active tissue lysis (Ritchie and Smith, 1998) . The only way to distinguish the two types is to observe the band progression over time.
No known pathogen
has been isolated (it has only been attempted for type II), although there is a documented shift in the composition of the population of bacteria
present in the surface mucopolysaccharide layer. The shift is from domination by pseudomonads to domination by Vibrio carchariae (Ritchie and Smith, 1995). Histopathological examination of white band Type I diseased tissue may reveal aggregates of gram negative bacteria in affected tissue (Peters et al., 1983) .
White band disease affects acroporids throughout the Caribbean and has decimated populations at a regional scale (Gladfelter, 1982; Peters et al. 1983; Aronson and Precht, 1997, 2001).
Other coral diseases are:
Coral
Corals are marine animals in class Anthozoa of phylum Cnidaria typically living in compact colonies of many identical individual "polyps". The group includes the important reef builders that inhabit tropical oceans and secrete calcium carbonate to form a hard skeleton.A coral "head" is a colony of...
tissue degradation of Caribbean
Caribbean
The Caribbean is a crescent-shaped group of islands more than 2,000 miles long separating the Gulf of Mexico and the Caribbean Sea, to the west and south, from the Atlantic Ocean, to the east and north...
acroporid corals. Two species are affected, Acropora palmata and A. cervicornis (Gladfelter, 1982). The disease exhibits a sharp demarcation between apparently healthy coral tissue and exposed coral skeleton. These signs are identical to White plague
White plague
White plague can refer to:* The British colonization of non-Caucasian parts of the world.* Any epidemic disease that makes the patients appear pale, especially tuberculosis during the 19th and early 20th century....
, except that white band is acroporid specific, whereas white plague has not been found on acroporids. Tissue loss usually proceeds from the base of the colony branch to the tip, although it can begin in the middle of a branch in A. cervicornis.
There are two distinct disease types that differ in the pattern of tissue loss. White band Type I exhibits tissue degradation associated with a line that migrates across the coral colony. There is no obvious microbial band, although the freshly exposed coral skeleton appears band like. Tissue lysis
Lysis
Lysis refers to the breaking down of a cell, often by viral, enzymic, or osmotic mechanisms that compromise its integrity. A fluid containing the contents of lysed cells is called a "lysate"....
is always associated with the moving front (which differentiates Type I from Type II). The rate of tissue loss varies from mm to cm/day (Peters et al., 1983). White band Type II also exhibits tissue degradation as a band moves across a coral colony, however in this case the moving front may, at times, have a bleached zone that catches up to active tissue lysis (Ritchie and Smith, 1998) . The only way to distinguish the two types is to observe the band progression over time.
No known pathogen
Pathogen
A pathogen gignomai "I give birth to") or infectious agent — colloquially, a germ — is a microbe or microorganism such as a virus, bacterium, prion, or fungus that causes disease in its animal or plant host...
has been isolated (it has only been attempted for type II), although there is a documented shift in the composition of the population of bacteria
Bacteria
Bacteria are a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria have a wide range of shapes, ranging from spheres to rods and spirals...
present in the surface mucopolysaccharide layer. The shift is from domination by pseudomonads to domination by Vibrio carchariae (Ritchie and Smith, 1995). Histopathological examination of white band Type I diseased tissue may reveal aggregates of gram negative bacteria in affected tissue (Peters et al., 1983) .
White band disease affects acroporids throughout the Caribbean and has decimated populations at a regional scale (Gladfelter, 1982; Peters et al. 1983; Aronson and Precht, 1997, 2001).
Other coral diseases are:
- Black band diseaseBlack band diseaseBlack band disease is characterized by complete coral tissue degradation due to a pathogenic microbial consortium that appears as a dark red or black migrating microbial mat. The mat is present between apparently healthy coral tissue and freshly exposed coral skeleton.-Appearance:Black Band disease...
, caused by a microbial consortiumMicrobial consortiumA microbial consortium is two or more microbial groups living symbiotically....
dominated by the cyanobacteria Phormidium corallyticum - Brown band disease Reported only from the Great Barrier Reef, etiologyEtiologyEtiology is the study of causation, or origination. The word is derived from the Greek , aitiologia, "giving a reason for" ....
at current unknown although the dense brown band preceding the disease lesion contains the presence of ciliateCiliateThe ciliates are a group of protozoans characterized by the presence of hair-like organelles called cilia, which are identical in structure to flagella but typically shorter and present in much larger numbers with a different undulating pattern than flagella...
s (although not to be mistaken with Helicostoma nonatum - see Willis et al. 2004) - Yellow-band diseaseYellow-band diseaseYellow-band disease is a disease that attacks colonies of coral at a time when coral is already under stress from pollution, overfishing, and climate change...
AKA Yellow blotch disease, thought to be caused by VibrioVibrioVibrio is a genus of Gram-negative bacteria possessing a curved rod shape, several species of which can cause foodborne infection, usually associated with eating undercooked seafood. Typically found in saltwater, Vibrio are facultative anaerobes that test positive for oxidase and do not form...
spp. - Skeletal Eroding BandSkeletal Eroding BandSkeletal eroding band is a disease of corals that appears a black or dark gray band that slowly advances over corals, leaving a spotted region of dead coral in its wake...
, associated with the ciliate Halofolliculina corallasiaHalofolliculina corallasiaHalofolliculina corallasia is a heterotrich ciliate identified as a cause of the syndrome called Skeletal Eroding Band . It is the first coral disease pathogen that is a protozoan as well as the first known to be an eucaryote; all others identified are bacteria... - White plague, caused by the bacterium Aurantimonas coralicida
- Black necrosing syndrome Affects gorgonian from the Great Barrier Reef, possibly a fungal pathogen similar to aspergillosisAspergillosisAspergillosis is the name given to a wide variety of diseases caused by fungi of the genus Aspergillus. The most common forms are allergic bronchopulmonary aspergillosis, pulmonary aspergilloma and invasive aspergillosis. Most humans inhale Aspergillus spores every day...
- Dark spots disease EtiologyEtiologyEtiology is the study of causation, or origination. The word is derived from the Greek , aitiologia, "giving a reason for" ....
currently unknown, possibly an environmental stressor rather than a true pathogenic disease. - Rapid Wasting Syndrome, possibly caused by a fungus growing on areas damaged by feeding action of the parrotfishParrotfishParrotfishes are a group of fishes that traditionally had been considered a family , but now often are considered a subfamily of the wrasses. They are found in relatively shallow tropical and subtropical oceans throughout the world, but with the largest species richness in the Indo-Pacific...
Sparisoma viride - White pox diseaseWhite pox diseaseWhite pox disease , first noted in 1996 on coral reefs near the Florida keys, is a coral disease affecting Elkhorn coral throughout the Caribbean. It causes irregular white patches or blotches on the coral that result from the loss of coral tissue...
, caused by the bacterium Serratia marcescensSerratia marcescensSerratia marcescens is a species of Gram-negative, rod-shaped bacterium in the family Enterobacteriaceae. A human pathogen, S. marcescens is involved in nosocomial infections, particularly catheter-associated bacteremia, urinary tract infections and wound infections, and is responsible for 1.4% of...