[Coral-List] sea cucumber disease
Esther Peters
esther.peters at verizon.net
Fri Mar 2 17:44:23 EST 2007
Megan,
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.
Abstract:
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
>>
>>
>>
>>
>> _________________________________________________________________
>>
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>>References
>>
>> 1. http://g.msn.com/8HMAENUS/2737??PS=47575
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