White pox disease
Encyclopedia
White pox disease first noted in 1996 on coral reef
s near the Florida keys
, is a coral disease affecting Elkhorn coral
(Acropora palmata) throughout the Caribbean
. It causes irregular white patches or blotches on the coral that result from the loss of coral tissue
. These patches distinguish white pox disease from white band disease
which produces a distinctive white band where the coral skeleton has been denuded. The blotches caused by this disease are also clearly differentiated from
coral bleaching
and scars caused by coral-eating snails. It is very contagious, spreading to nearby coral.
At the locations where white pox disease has been observed, it is estimated to have reduced the living tissue in elkhorn corals by 50-80%. In the Florida Keys National Marine Sanctuary
(FKNMS), the losses of living coral are estimated to average 88%. Elkhorn coral was formerly the dominant shallow water reef-building coral throughout the Caribbean but now is listed as a threatened, due in part to disease. This is the first species of coral to be listed as threatened in the United States
.
The pathogen responsible has identified as Serratia marcescens
, a common fecal intestinal
bacterium found in humans and other animals. This is the first time it has been linked to the death of coral. The specific source of the bacteria that is killing the coral is currently unknown. As well as living in animal and human intestines, S. marcescens can live in soil and water as an independent microbe.
The causes for the majority of known coral diseases have not been identified. It is of vital importance to understand the relationship between coral health and environmental factors in the study of coral disease.
Much more research is needed to examine the variety of potential sources for genotype
s similar to the Serratia
pathogen. Possible sources
include the effluents of waste water and septic tanks, as well as reef fishes feces and seabird
guano. The human origin of the white pox bacteria must be determined before the managers of coral reef ecosystems and waste water treatment engineers can work toward finding a solution.
Coral reef
Coral reefs are underwater structures made from calcium carbonate secreted by corals. Coral reefs are colonies of tiny living animals found in marine waters that contain few nutrients. Most coral reefs are built from stony corals, which in turn consist of polyps that cluster in groups. The polyps...
s near the Florida keys
Florida Keys
The Florida Keys are a coral archipelago in southeast United States. They begin at the southeastern tip of the Florida peninsula, about south of Miami, and extend in a gentle arc south-southwest and then westward to Key West, the westernmost of the inhabited islands, and on to the uninhabited Dry...
, is a coral disease affecting Elkhorn coral
Elkhorn coral
Elkhorn coral is considered to be one of the most important reef-building corals in the Caribbean. This species of coral is structurally complex with many large branches. The coral structure closely resembles that of elk antlers. These branches create habitats for many other reef species such as...
(Acropora palmata) throughout the 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...
. It causes irregular white patches or blotches on the coral that result from the loss of coral tissue
Tissue (biology)
Tissue is a cellular organizational level intermediate between cells and a complete organism. A tissue is an ensemble of cells, not necessarily identical, but from the same origin, that together carry out a specific function. These are called tissues because of their identical functioning...
. These patches distinguish white pox disease from white band disease
White band disease
White band disease is characterized by complete coral tissue degradation of Caribbean acroporid corals. Two species are affected, Acropora palmata and A. cervicornis . The disease exhibits a sharp demarcation between apparently healthy coral tissue and exposed coral skeleton...
which produces a distinctive white band where the coral skeleton has been denuded. The blotches caused by this disease are also clearly differentiated from
coral bleaching
Coral bleaching
Coral bleaching is the loss of intracellular endosymbionts through either expulsion or loss of algal pigmentation.The corals that form the structure of the great reef ecosystems of tropical seas depend upon a symbiotic relationship with unicellular flagellate protozoa, called zooxanthellae, that...
and scars caused by coral-eating snails. It is very contagious, spreading to nearby coral.
At the locations where white pox disease has been observed, it is estimated to have reduced the living tissue in elkhorn corals by 50-80%. In the Florida Keys National Marine Sanctuary
Florida Keys National Marine Sanctuary
The Florida Keys National Marine Sanctuary is a U.S. National Marine Sanctuary in the Florida Keys. It includes the Florida Reef, the only barrier coral reef in North America and the third-largest coral barrier reef in the world. It also has extensive mangrove forest and seagrass fields...
(FKNMS), the losses of living coral are estimated to average 88%. Elkhorn coral was formerly the dominant shallow water reef-building coral throughout the Caribbean but now is listed as a threatened, due in part to disease. This is the first species of coral to be listed as threatened in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
.
Pathogen
Serratia marcescens
Serratia 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...
, a common fecal intestinal
Intestine
In human anatomy, the intestine is the segment of the alimentary canal extending from the pyloric sphincter of the stomach to the anus and, in humans and other mammals, consists of two segments, the small intestine and the large intestine...
bacterium found in humans and other animals. This is the first time it has been linked to the death of coral. The specific source of the bacteria that is killing the coral is currently unknown. As well as living in animal and human intestines, S. marcescens can live in soil and water as an independent microbe.
The causes for the majority of known coral diseases have not been identified. It is of vital importance to understand the relationship between coral health and environmental factors in the study of coral disease.
Much more research is needed to examine the variety of potential sources for genotype
Genotype
The genotype is the genetic makeup of a cell, an organism, or an individual usually with reference to a specific character under consideration...
s similar to the Serratia
Serratia
Serratia is a genus of Gram-negative, facultatively anaerobic, rod-shaped bacteria of the Enterobacteriaceae family. The most common species in the genus, S. marcescens, is normally the only pathogen and usually causes nosocomial infections. However, rare strains of S. plymuthica, S. liquefaciens,...
pathogen. Possible sources
include the effluents of waste water and septic tanks, as well as reef fishes feces and seabird
guano. The human origin of the white pox bacteria must be determined before the managers of coral reef ecosystems and waste water treatment engineers can work toward finding a solution.