White Plague/ White Band/ White Syndrome

[emissary43]

So I have recently been brushing up on my coral diseases and I found some very interesting information on whiteband/white plague. (I realize these are generally considered different but considering total lack of information on both and the similarities in symptoms I will lump them together until proven otherwise.)

So article one:

Sussman M, Willis BL, Victor S, Bourne DG (2008) Coral Pathogens Identified for White Syndrome (WS) Epizootics in the Indo-Pacific. PLoS ONE 3(6): e2393. doi:10.1371/journal.pone.0002393

found strong evidence to support the hypothesis that γ-Proteobacteria family Vibrionacae are responsible for as they label it white syndrome. They found 6 strains of the bacteria in various Indonesian regions but all significantly were genetically similar.

At this point it is important to note that a Vibrionaceae gram negative bacteria infection in humans is also known as Necrotising fasciitis.

That said I point you to this article:

GM Joynt, CD Gomersall, DJ Lyon (1999) Severe necrotising fasciitis of the extremities caused by Vibrionaceae: experience of a Hong Kong tertiary
hospital. HKMJ ;5:63-8


suggesting that marine Vibrionacae can infect humans. I am unsure whether or not the strains specifically infecting corals currently in the trade can infect humans but I believe when dealing with potentially fatal results that caution is theoften overlooked best policy. Which means please wear gloves when dealing with any coral or fish disease!

Which brings me to my question to those more acquainted with the intricacies of the nature of various antibiotics.

You cannot dose a reef with tetracycline because the pH is too high. What else may work?

What about Doxycycline Hydrochloride? it remains active at reef standard pH, will it kill everything else as well?

If not Doxycycline Hydrochloride how about Kanamycin Sulfate, third generation cephalosporin, and
fluoroquinolone?

Please back up your assertions. Thank you for reading.

 

[emissary43]

I realized that I should probably have described the diseases. Here is a quote from the NOAA's site. It is a bit outdated being based on data prior to 2000 but it gives you a general idea of the disease.

White-band Disease
White-band disease (WBD) was first identified in 1977 on reefs surrounding St. Croix. It is now known to occur throughout the Caribbean where it is believed to only affect staghorn and elkhorn corals (Green and Bruckner, 2000). This disease is characterized by tissue that peels or sloughs off the coral skeleton in a uniform band, generally beginning at the base of the colony and working its way up to branch tips (Peters, 1997). The band ranges from a few millimeters up to 10 cm wide, and tissue is lost at a rate of about 5 mm per day (Gladfelter, 1991).The effects of WBD can be devastating. In fact, WBD is thought to be a major factor in the decline of elkhorn and staghorn corals in the wider Caribbean (Aronson and Precht, 2001). Since the 1980s, Acropora cervicornis has been virtually eliminated from reef environments throughout the region. In the U.S. Virgin Islands, populations of Acropora palmata declined from 85 percent cover to 5 percent within 10 years, primarily as a result of WBD (Gladfelter, 1991). WBD currently is the only coral disease known to cause major changes in the composition and structure of reefs (Green and Bruckner, 2000).

Scientists have distinguished two forms of WBD. Type II, first identified on staghorn corals in the Bahamas in 1997, differs from type I in that tissue adjacent to exposed skeleton bleaches before it dies. Type II WBD sometimes is mistaken for bleaching (Ritchie and Smith, 1998).

The cause of WBD is unknown. Though unusual aggregates of rod-shaped bacteria were found in the tissue of corals affected by WBD type I, scientists have not determined the role of this microorganism. To further complicate matters, some corals that contain these bacteria appear healthy, and other colonies that are affected by sloughing tissue do not contain the bacteria (Richardson, 1998). More recently, scientists reported a species of bacteria associated with type II (Ritchie and Smith, 1998).

WBD has also been found throughout the Red Sea and Indo-Pacific, including the Philippines, the Great Barrier Reef and Indonesia. Unlike reports of WBD from the Caribbean, this condition has been identified on 34 species of massive, plating and branching corals in nine countries in the Indo-Pacific (Green and Bruckner, 2000).

White Plague

White plague is similar in appearance to WBD, but it affects different species. The disease is characterized by an abrupt line or band of white, exposed coral skeleton that separates living tissue from algal-colonized skeleton, and often a narrow band of bleached tissue may be visible adjacent to exposed skeleton. Usually beginning at the base of a colony, it spreads quickly upward and outward.

White plague was first identified in the Florida Keys in 1977. A second form, type II, was identified on the same reefs in 1995, and a third form (type III) was reported in 2000 (Richardson and Aronson, in press). The three types of plague are similar in appearance, although a greater number of species are affected by type II. Additionally, the rate of tissue mortality is much greater in type II and type III than in type I (Richardson, 1998; Richardson and Aronson, in press).

Plague type I is reported to affect 10 species of corals, causing coral tissue mortality at a rate of about 3 mm/day. In Plague type II, up to 2 cm of tissue per day succumb to the disease, and small colonies can be decimated within one to two days. Thirty-two species are reported to be affected by this condition (Richardson, 1998). Plague type III affects the largest reef-building corals, including C. natans and M. annularis, and tissue loss is much greater than that observed in either plague type I or plague type II (Richardson and Aronson, in press).

It is not entirly clear how different or similar the causes of these two diseases are but the symptoms are nearly identical. For those who will inevitably request photos many can be found in various google image searches like the one linked below:

"White Plague Coral" Google Images Search

 

[emissary43]

I just found another good website references some work done in 2005 that atributes White plague to a different gram negative bacteria. Specifically white plague type II, is caused by the c-proteobacterium Thalassamonas loyana (Efrony et al., 2007), and occurs on the Eilat coral reef (Gulf of Aqaba, Red Sea) in the species Favia favius. Check the site out.

I still think a broad spectrum gram negative antibiotic is the way to go.

 

[greenbean36191]

Vibrionaceae are ubiquitous in marine environments and are among the most common bacteria found on healthy corals. Most are thought to be mutualistic or commensal symbionts rather than pathogens. Gammaproteobacteria, which includes the Vibrionaceae, typically account for about 50-80% of the bacteria on healthy corals, with the Vibrionaceae themselves accounting for about 20%. It would be very difficult to specifically target the pathogenic bacteria without simultaneously wiping out the rest of the desirable bacteria, which are also gram-negative proteobacteria, many of them in the same genus as the pathogen. While use of antibiotics in a last-ditch effort to save infected corals might be called for, prophylactic use on corals that don't show signs of white plague is likely to do more harm than good.

 

[BadSquishy]

Chloramphenicol is effective in the ph range of the reef tank. Broad spectrum activity with gram positive/negative and against anaerobic organisms. Cheap - reportedly effective against RTN and brown jelly - which agrees with my experience and use.
Not a new treatment - has been used for years in aquaculture although not readily known or available (still used in veterinary medicine as treatment for urinary tract infections in dogs) Caution, has been reported to cause aplastic anaemia in susceptible individuals - rare.

I've used it as last-ditch dip to save dying corals with mixed results. Definitely superior antibacterial. I dip for shorter duration at slightly higher than recommended concentrations.

 

[emissary43]

Vibrionaceae are ubiquitous in marine environments and are among the most common bacteria found on healthy corals. Most are thought to be mutualistic or commensal symbionts rather than pathogens. Gammaproteobacteria, which includes the Vibrionaceae, typically account for about 50-80% of the bacteria on healthy corals, with the Vibrionaceae themselves accounting for about 20%. It would be very difficult to specifically target the pathogenic bacteria without simultaneously wiping out the rest of the desirable bacteria, which are also gram-negative proteobacteria, many of them in the same genus as the pathogen. While use of antibiotics in a last-ditch effort to save infected corals might be called for, prophylactic use on corals that don't show signs of white plague is likely to do more harm than good.

Thanks for adding, I read that same information you posted. Of course we all know that antibiotics are more of a broad sword than a scalpel. But we are discussing an ailment that could potentially wipe out entire aquaculture facilities. Considering the problem bacteria exists in the water column as well as on the affected specimens; removal and quarantine would most often be ineffective for elimination. I imagine in most cases with small collections all the vulnerable species will be eliminated and then the disease will stop Resulting in the assumption that the ailment was defeated or the conditions were improved sufficiently.

Just like any antibiotic application you balance the reduction in beneficial bacterial species with that of the virulent ones. The question is whether or not there is an option that would be generally safe and would allow for reasonably quick regeneration of beneficial bacteria colonies. In many ways a reef system will respond like a human body.

 

[greenbean36191]

Well the prevailing hypothesis at the moment is that the normal bacterial assemblage functions somewhat like an immune system for corals. It's the competition between all the members of the assemblage that prevent other members like V. coralliilyticus from having population explosions. You only get those explosions when something in the environment changes to give one species a competitive advantage over another (or you inoculate the coral with a large number of the pathogenic bacteria).

If you use antibiotics to go after gammaproteobacteria you may kill the pathogen, but you're essentially wiping out the corals' immune systems as well.

If the corals are in a closed system where you can eliminate the pathogen from the water column and you're going to lose the corals anyway if you don't treat, use of antibiotics might make sense. However, neither white plague nor WBD have been reported in captivity except after intentional infection, so I'm not sure it's really a major threat to aquaculture. Even species like A. cervicornis that have been essentially wiped out in the wild by WBD have long been grown from infected populations and even after direct physical contact with infected colonies without issue.

WBD and white plague are a bigger threat to farms in the ocean, but in that case antibiotics are less useful anyway. You can pull the corals to treat them, but then you'd have to keep them in a closed system at least until their normal bacteria have recovered (and no one knows how long that is). Most farms don't have the resources to do that.