White plague (coral disease)

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White plague is a suite of coral diseases of which three types have been identified, initially in the Florida Keys. They are infectious diseases but it has proved difficult to identify the pathogens involved. White plague type II may be caused by the gram negative bacterium Aurantimonas coralicida in the order Rhizobiales but other bacteria have also been associated with diseased corals and viruses may also be implicated.

Coral diseases, comprising the diseases that affect corals, injure the living tissues and often result in the death of part or the whole of the colony. These diseases have been occurring more frequently in the twenty-first century as conditions become more stressful for many shallow-water corals. The pathogens causing the diseases include bacteria, fungi and protozoa, but it is not always possible to identify the pathogen involved.

Florida Keys Coral cay archipelago in Florida, United States of America

The Florida Keys are a coral cay archipelago located off the southern coast of Florida, forming the southernmost portion of the continental United States. They begin at the southeastern coast of the Florida peninsula, about 15 miles (24 km) 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 Tortugas. The islands lie along the Florida Straits, dividing the Atlantic Ocean to the east from the Gulf of Mexico to the northwest, and defining one edge of Florida Bay. At the nearest point, the southern part of Key West is just 90 miles (140 km) from Cuba. The Florida Keys are between about 23.5 and 25.5 degrees North latitude.

In biology, a pathogen, in the oldest and broadest sense, is anything that can produce disease. A pathogen may also be referred to as an infectious agent, or simply a germ.

Contents

History

In 1977, a disease of scleractinian corals appeared on reefs off the Florida Keys in the United States and was termed white plague. It caused white lesions and was shown to be an infectious disease, being particularly prevalent in Mycetophyllia ferox . This disease caused little mortality and occurred sporadically, but was still present in the area in 1984. It is now known as white plague type 1. [1]

In 1995, a new coral disease was described as an epizootic disease in the same reefs in the Florida Keys. Many species of coral found in the area were affected and the mortality rate of these was up to 38%. The pathogen involved was found to be a previously unknown species of bacterium in the order Rhizobiales, which was placed in the newly created genus Aurantimonas and given the name Aurantimonas coralicida , and the disease was described as white plague type 2. [2] The pathogen was isolated from a diseased colony of Dichocoenia stokesi and cultured in the laboratory, subsequently being used to inoculate two healthy colonies which then developed the disease. [3] In the next few months, it had spread over 200 km (124 mi) of reef and was killing seventeen species of coral. Over the next four years, it spread further, but was most severe in different regions each year. [1]

In epizoology, an epizootic is a disease event in a nonhuman animal population, analogous to an epidemic in humans. An epizootic may be: restricted to a specific locale, general, or widespread ("panzootic"). High population density is a major contributing factor to epizootics. Aquaculture is an industry sometimes plagued by disease because of the large number of fish confined to a small area.

Aurantimonas is a genus of bacteria from the family of Aurantimonadaceae.

Aurantimonas coralicida is a gram-negative bacterium, and a causative agent of white plague in Caribbean corals. It is rod-shaped, with polar flagella.

White plague is an enigmatic disease. Further research cast into doubt the role of A. coralicida as a causative agent by finding that bacterium on healthy parts of colonies of Orbicella annularis affected by white plague disease but absent from diseased parts. In these diseased colonies, an α-proteobacterium similar to one which causes a disease in juvenile oysters has been implicated, being found on the diseased parts of the coral but not on the sound tissues. These anomalous findings may be caused by the fact that there are two or more diseases with similar symptoms, both known as white plague. [3]

<i>Orbicella annularis</i> species of Anthozoa

Orbicella annularis, commonly known as the boulder star coral, is a species of coral that lives in the western Atlantic Ocean and is the most thoroughly studied and most abundant species of reef-building coral in the Caribbean to date. It also has a comprehensive fossil record within the Caribbean. This species complex has long been considered a generalist that exists at depths between 0 and 80 meters that grew into varying colony shapes in response to differing light conditions. Only recently with the help of molecular techniques has O. annularis been shown to be a complex of at least three separate species. Those species are divided into O. annularis, O. faveolata, and O. franksi. This coral was originally described as Montastraea annularis.

In 1999, a third and still more virulent variant appeared in the northern Florida Keys. White plague type III mostly affected Colpophyllia natans and Orbicella annularis . [4]

A white-plague like disease reported from the Red Sea in 2005 has been shown to be caused by a different bacterial pathogen, Thalassomonas loyana . Further research has shown that viruses may be involved in white plague infections, the coral small circular ssDNA viruses (SCSDVs) being present in association with diseased tissue. This group of viruses is known to cause disease in plants and animals. [5]

Red Sea Arm of the Indian Ocean between Arabia and Africa

The Red Sea is a seawater inlet of the Indian Ocean, lying between Africa and Asia. The connection to the ocean is in the south through the Bab el Mandeb strait and the Gulf of Aden. To the north lie the Sinai Peninsula, the Gulf of Aqaba, and the Gulf of Suez. The Red Sea is a Global 200 ecoregion. The sea is underlain by the Red Sea Rift which is part of the Great Rift Valley.

Description

As first described by Dunstan in 1977, white plague type 1 produces lesions on any part of the colony. These increase gradually in size, advancing at the rate of a few millimetres per day. The advancing edge exhibits a sharp boundary between the apparently healthy tissue and the bare skeleton. Type II, first appearing in 1995 is similar, but it usually starts at the base of the colony, and the edge advances at a faster rate, up to 2 cm (0.8 in) per day. [4] White plague type III advances at a rate in excess of two centimetres per day. [5]

Related Research Articles

A human pathogen is a pathogen that causes disease in humans.

Infection invasion of a host by disease-causing organisms

Infection is the invasion of an organism's body tissues by disease-causing agents, their multiplication, and the reaction of host tissues to the infectious agents and the toxins they produce. Infectious disease, also known as transmissible disease or communicable disease, is illness resulting from an infection.

Scleractinia Order of cnidarians

Scleractinia, also called stony corals or hard corals, are marine animals in the phylum Cnidaria that build themselves a hard skeleton. The individual animals are known as polyps and have a cylindrical body crowned by an oral disc in which a mouth is fringed with tentacles. Although some species are solitary, most are colonial. The founding polyp settles and starts to secrete calcium carbonate to protect its soft body. Solitary corals can be as much as 25 cm (10 in) across but in colonial species the polyps are usually only a few millimetres in diameter. These polyps reproduce asexually by budding, but remain attached to each other, forming a multi-polyp colony of clones with a common skeleton, which may be up to several metres in diameter or height according to species.

White plague may refer to:

Pillar coral coral

Pillar coral is a hard coral found in the western Atlantic Ocean and the Caribbean Sea. It is the only species in the monotypic genus Dendrogyra. It is a digitate coral -that is, it resembles fingers or a cluster of cigars, growing up from the sea floor without any secondary branching. It is large and can grow on both flat and sloping surfaces at depths down to 20 m (65 ft). It is one of the few types of hard coral in which the polyps can commonly be seen feeding during the day.

The Aurantimonadaceae are a small family of marine bacteria. Six species are known. Aurantimonas coralicida causes a white plague in corals. Fulvimarina pelagi was isolated from seawater, and takes the form of nonmotile rods.

White band disease A Deadly Coral Diseases! 😮

White band disease is a coral disease that affects acroporid corals and is distinguishable by the white band of dead coral tissue that it forms. The disease completely destroys the coral tissue of Caribbean acroporid corals, specifically elkhorn coral and staghorn coral. The disease exhibits a pronounced division between the remaining coral tissue and the exposed coral skeleton. These symptoms are similar to white plague, except that white band disease is only found on acroporid corals, and white plague has not been found on any acroporid corals. It is part of a class of similar disease known as "white syndromes", many of which may be linked to species of Vibrio bacteria. While the pathogen for this disease has not been identified, Vibrio carchariae may be one of its factors. The degradation of coral tissue usually begins at the base of the coral, working its way up to the branch tips, but it can begin in the middle of a branch.

Black band disease coral disease

Black band disease is a coral disease in which corals develop a black band. It is characterized by complete tissue degradation due to a pathogenic microbial consortium. The mat is present between apparently healthy coral tissue and freshly exposed coral skeleton.

Elkhorn coral species of cnidarian

Elkhorn coral is a prominent Caribbean reef-building coral, although current populations are still struggling to recover from white band disease outbreak. This species is structurally complex with many large branches. The coral structure resembles that of elk antlers. These branches create habitats for many other reef species, such as lobsters, parrot-fish, snapper shrimps and other reef fish. Elkhorn coral colonies are incredibly fast-growing, with an average growth rate of 5 to 10 cm per year and can eventually grow up to 3.7 m (12 ft) in diameter. The color of this coral species ranges from brown to a yellowish-brown as a result of the symbiotic zooxanthellae living inside the tissue of this coral species. Zooxanthellae are a type of algae which photosynthesize to provide the coral with nutrients. The zooxanthellae are also capable of removing waste products from the coral. Historically, the majority of elkhorn coral reproduction has occurred asexually; this occurs when a branch of the coral breaks off and attaches to the substrate, forming a new colony, known as fragmentation. The degree to which local stands reproduce by fragmentation varies across the Caribbean, but on average, 50% of colonies are the result of fragmentation rather than sexual reproduction. Sexual reproduction occurs once a year in August or September when coral colonies release millions of gametes by broadcast spawning.

Skeletal eroding band (SEB) is a disease of corals that appears as a black or dark gray band that slowly advances over corals, leaving a spotted region of dead coral in its wake. It is the most common disease of corals in the Indian and Pacific Oceans, and is also found in the Red Sea.

White pox disease

White 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. 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.

Yellow-band disease coral disease

Yellow-band disease is a coral disease that attacks colonies of coral at a time when coral is already under stress from pollution, overfishing, and climate change. It is characterized by large blotches or patches of bleached, yellowed tissue on Caribbean scleractinian corals.

Environmental issues with coral reefs

Human impact on coral reefs is significant. Coral reefs are dying around the world. Damaging activities include coral mining, pollution, overfishing, blast fishing, the digging of canals and access into islands and bays. Other dangers include disease, destructive fishing practices and warming oceans. Factors that affect coral reefs include the ocean's role as a carbon dioxide sink, atmospheric changes, ultraviolet light, ocean acidification, viruses, impacts of dust storms carrying agents to far-flung reefs, pollutants, algal blooms and others. Reefs are threatened well beyond coastal areas. Climate change, such as warming temperatures, causes coral bleaching, which if severe kills the coral.

<i>Orbicella faveolata</i> species of cnidarian

Orbicella faveolata, commonly known as mountainous star coral, is a colonial stony coral in the family Merulinidae. It is native to the Caribbean Sea and the Gulf of Mexico and is listed as "endangered" by the International Union for Conservation of Nature. This species was formerly known as Montastraea faveolata.

<i>Orbicella franksi</i> species of cnidarian

Orbicella franksi, commonly known as boulder star coral, is a colonial stony coral in the family Merulinidae. It is native to shallow waters in the Caribbean Sea, the Gulf of Mexico, the Bahamas, Bermuda and Florida, and is listed as a "vulnerable species" by the International Union for Conservation of Nature.

Coral reefs of the Virgin Islands

One of the marine ecosystems found in the Virgin Islands are the coral reefs. These coral reefs can be located between the islands of St. Croix, St. Thomas, and St. John. These coral reefs have an area of 297.9 km2, along with other marine habitats that are in between. The way these coral reefs grow are by coral larvae swimming freely and attaching themselves to hard surfaces around the islands and start to develop a skeleton on the outside of their skin to protect themselves from predators but also allow a new place for other coral larvae to attach to and grow on. These corals can form into three different structures; fringing reefs, which are reefs that are close to the shore, barrier reefs, which are reefs that are alongside the shore and is separated by deep water, and an atoll reef which is a coral reef that circles a lagoon or body of water.

Thalassotalea loyana is a bacterium from the genus of Thalassotalea. Thalassomonas loyana can cause white plague disease in the coral Favia favus.

References

  1. 1 2 Woodley, Cheryl M.; Downs, Craig A.; Bruckner, Andrew W.; Porter, James W.; Galloway, Sylvia B. (2016). Diseases of Coral. John Wiley & Sons. p. 64. ISBN   978-0-8138-2411-6.
  2. ↑ Denner, E.B.M. (2003). "Aurantimonas coralicida gen. nov., sp. nov., the causative agent of white plague type II on Caribbean scleractinian corals". International Journal of Systematic and Evolutionary Microbiology. 53 (4): 1115–1122. doi:10.1099/ijs.0.02359-0. ISSN   1466-5026. PMID   12892136.
  3. 1 2 Woodley, Cheryl M.; Downs, Craig A.; Bruckner, Andrew W.; Porter, James W.; Galloway, Sylvia B. (2016). Diseases of Coral. John Wiley & Sons. pp. 324–326. ISBN   978-0-8138-2411-6.
  4. 1 2 Rosenberg, Eugene; Loya, Yossi (2004). Coral Health and Disease. Springer Science & Business Media. p. 352. ISBN   978-3-540-20772-6.
  5. 1 2 Soffer, Nitzan; Brandt, Marilyn E.; Correa, Adrienne M.S.; Smith, Tyler B.; Thurber, Rebecca Vega (2014). "Potential role of viruses in white plague coral disease". ISME Journal. 8 (2): 271–283. doi:10.1038/ismej.2013.137. PMC   3906806  Lock-green.svg.
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