5. Overview of leucorrhea:
Leucorrhea is characβ ≤terized by complete degradation of the c★★oral tissue of Caribbean $↑↑≈staghorn corals. There are two species affe✔¶↓cted, one is the palmophyllum st£€<aghorn coral and the other is cervicornΩis staghorn (Gladfelter, 1982). The×÷∏ disease draws a sharp line¶↕Ω between apparently healthy coral tis←•sue and exposed coral skele∑™δton. These symptoms are>€∞≠ the same as white blight ✔↓, except that the white band i₩÷₩s unique to staghorn corals (and white blight× has not been found in staghorn corals). Tissue α≠loss usually begins from the base of the br£δ§λanch to the tip, but can alsβ≤₩o start from the midd§>βle of the branch. The"<re are two distinct disease types ε§λ₩that differ in tissue loss pa✔πtterns. Leucorrhea type I exhibits tissue de∑∞β®gradation associated with lines t₩∏hat migrate throughout co™♦±ral colonies. Althou&β ≠gh the newly exposed coral ×✘skeletons were banded, there were no £₩♣distinct microbial bands. Tissα←"φue lysis is always associated with a ←→moving leading edge (this αΩΩis the difference between Type I and Type IIαλα$. Tissue loss rates vary from m€∞∑®m to cm/day. Type II leucor≥σ✔&rhea also exhibits tissue degradation aλ₽₩£s it travels through corα™al colonies, but in In this case, mov∏αement sometimes occurs in areas of alb"π★inism, catching up with active tissue↓♣•₹ lysis (Ritchie and Sγ€÷mith, 1998). The only¥↓'< way to distinguish th₩¥→e two types is to observe the progres©"sion of the bands over time.
Leucorrhea disease affects staghorn corals thrφλβoughout the Caribbean and causes massive coral ♦die-offs on a regional scale.
Image: Leucorrhea has two causes, type¥✔ I and type II. In type I, tissu "λ☆e destruction is associated with anterior movem∏¥↔ent of the band. In type II, the♣®>re is sometimes an albino zone between th€'e tissue degradation zone and the shif≈↕ting peak zone. Type I is visu"¥'•ally indistinguishable from type I>≠ I if there is no whitening zone. No pathogen ™s have been isolated ☆≠so far.
6. Overview of Leukemia
White blight is characterized ♣by a sharp demarcation lα ine between apparently he∞βalthy coral tissue and exposed coral skeleton.∑∞₩✔ No obvious microbial zone wa©εs seen. The blight is caused by a bacteλ >rial pathogen (Aurantimonas cor&∑alicida). Disease si⶙gns (rates and patte↓λ ♦rns of disease progression and toxic≠₩÷ity) differed between the three differen←π♠t types. Type I blight, rec✘↓orded in the 1970s and 1980s, started on φ✘both sides of the colony, wiᥧ₽th tissue destruction at a rate ☆↓∏of 3 mm per day. Six species of coral are repδσ<₹orted to be affected. Type II blight, first recαπ₩orded in 1995, starts at the bottom of cora¶l colonies and progresses u£ §∞pwards, with tissue damage up to✔ 2 cm/day. Whitened areas (<3 mm) may ex™>ist between healthy tissue a↕¶nd exposed bone. Type III bligλ™≠ht, which first emerged in 1999, begins∏↓ at the flanks or top of✔ the colony and destroys tissue at a h♥§igh rate of dm per day. . White blight↔≈ is currently endemi↔≈♠c throughout the Caribbean,λ≤ affecting 33 species of Caribbeα→βan stony corals (Weil et al, in press). The so™€γurce is not yet known.
7. Overview of white pox
White pox is characterized by the degradation <₩of coral tissue, the rapid loss of coral&§ tissue along a distinct line, or the presence™<↓€ of small residual tissue anywhere above or below↑≥ branches, sometimes near the eλ§dges of irregularly shaped patches. The a¶∏✘verage tissue loss rate i<s 2.5 cm2/day, but can be as high as 10.5 ™•↑®cm2/day.
Image: White pox is ch↓→aracterized by round lesions. The pathogen↕♣₩ is Serratia marcescens, a gram-negative enter≈λobacter
8. Overview of Yellow Belt Disease
Yellow band disease is characterized by la≥← 'rge rings or patches of blea≥✔₩φched yellow tissue in Caribb π≠≤ean reef-building corals. I↕§t spreads widely in the Caribbean. ✘÷↑≈Tissue loss is extremely slo≤≠♠w (cm/year). When yellow-banded corals also ₹↓suffer from bleaching λ÷®, the yellow-banding can be mixed with bleα₽ ached features; after recoε♥very from bleaching, the yellow-ban →ding is visible again. Althβε×ough loss of zooxanthellae pigments and zoo•£☆xanthellae cells has been found in affected ti≤σ¶ssues, no pathogen has been ident'≥ ified. Zooxanthellae →•>₹associated with the yellow b∏∞elt have a lower mitotic index (the number of di∏∑™'viding cells), and it has beeγ&n suggested that the disease affects zooxanthel₹₽π♥lae rather than corals.
Image: The yellow band is chara€€×÷cterized by a light-÷♠≥like expansion of the albino band. Minima≠£l tissue loss (cm/year). No pathogens♥♠Ω♣ were isolated.
Source: NOAA