[Coral-List] sea cucumber disease

Esther Peters esther.peters at verizon.net
Fri Mar 2 17:44:23 EST 2007


I reviewed diseases of echinoderms in this book chapter several years ago:

Peters, E.C.  1993.  Diseases of other invertebrate phyla: Porifera, 
Cnidaria, Ctenophora, Annelida, Echinodermata. In Pathobiology of Marine 
and Estuarine Organisms, ed. J.A. Couch and J.W. Fournie, pp. 393-449. 
CRC Press, Boca Raton, Florida, USA.

There were not any reports back then of this disease, as I recall.

A quick Google Scholar search brought up this paper:

Becker, P., Gillan, D., Lanterbecq, D., Jangoux, M., Rasolofonirina, R., 
Rakotovao, J., Eeckhaut, I. 2004. The skin ulceration disease in 
cultivated juveniles of Holothuria scabra (Holothuroidea, 
Echinodermata).  Aquaculture 242(No. 1/4):13-30.

It is frequently reported that cultivated holothuroids can suffer from a 
disease affecting their integument. We report here on a disease of 
juvenile Holothuria scabra, the widely marketed edible sea cucumber, 
reared in the Aqua-Lab hatchery of Toliara, Madagascar. This disease, 
which has been called skin ulceration disease, is very contagious and 
results from a severe bacterial infection that causes death within 3 
days. The first sign of the infection is a white spot that appears on 
the integument of individuals, close to the cloacal aperture. The spot 
extends quickly onto the whole integument leading to the death of 
individuals. Microscopic (histology, scanning and transmission electron 
microscopies) and biomolecular (denaturing gradient gel electrophoresis 
(DGGE) and sequencing) techniques have been used to describe the lesions 
and to investigate the infecting microbial communities. The lesions 
consist in a zone where the epidermis is totally destroyed and where 
collagen fibres and ossicles are exposed to the external medium. This 
zone is surrounded by a border line where degrading epidermis is mixed 
with the connective tissue. Lesions include three bacterial morphotypes: 
rod-shaped bacteria, rough ovoid bacteria, and smooth ovoid bacteria. 
The last morphotype is the only one found on the ossicles and is assumed 
to be responsible for their degradation. Three species of bacteria have 
been put in evidence in the lesions thanks to biomolecular analyses: 
Vibrio sp., Bacteroides sp., and an a-Proteobacterium. Infection assays 
of healthy holothuroids have been performed from lesions and from 
bacterial cultures but the causative agent has not been identified. It 
is suggested that combined events or agents, including bacteria, are 
required to induce the disease.

Pierre Becker is at the Université de Mons-Hainaut, Mons, Belgium.  I 
did not find his e-mail address in this quick search.  This sounds like 
what you are seeing.  These disease signs are probably not as 
"disease-specific" (pathognomonic) as one might wish (as with the 
Diadema mass mortality, other urchins have shown similar disease signs 
at various times and locations, but we aren't sure they were all caused 
by the same agent(s)).  As you can see from the above paper, 
histopathology, microbiology, and molecular techniques would be needed 
for diagnosis.  As John Cubit notes, it is very important to keep 
records of where and when diseased organisms are found.  Are the sea 
cucumbers in an area with "good" or "poor" water quality?  Could they be 
exposed to effluent from a sea cucumber culturing facility (or are they 
in one)?  You should have your students try to contact Dr. Becker and 
see if he can help you work on this disease.

Esther Peters

John Cubit wrote:

> Megan --- We have seen epidemics of diseases with similar symptoms cause 
> mass mortality of other echinoderms (sea urchins and starfish) elsewhere 
> in the world.  When my colleagues and I tracked the great die-off of 
> Diadema antillarum through the Caribbean and into the Western Atlantic, 
> reports like yours were  helpful in documenting the pattern of spread, 
> which better fit a model of spreading contagious disease rather than 
> models based on chemical contaminants or other physical causes, per se. 
> If no one is working on this already, recording the timing and spatial 
> (including geographic) pattern of mortality for the sea cucumbers could 
> be a valuable learning experience for your students as well as providing 
> valuable data for persons investigating this disease or the population 
> biology of the sea cucumbers.  --- John
> megan berkle wrote:
>>  Dear coral-listers:
>>  The   sea  cucumbers off  the  island  of  Rota,  N.  Marianas  island
>>  chain appear  to  have  a  disease.   It  appears that there is tissue
>>  necrosis leaving white spots all over their bodies.  Does anyone study
>>  sea cucumber disease?
>>  Megan Berkle
>>  Marine Science teacher, N. Marianas Islands
>>    _________________________________________________________________
>>  [1]Dont  miss  your  chance to WIN 10 hours of private jet travel from
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>>Coral-List at coral.aoml.noaa.gov

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