Dear Colleagues,
as a follow up to a posting on skin anomaly observed in a bottlenose
dolphin off La Gomera (Canary islands, see http://m-e-e-r.de/511.1.html
<http://m-e-e-r.de/511.1.html>), I would like to summarize the feedback
by many of you. Thanks to everyone who provided advice and suggestions.
I appreciate that it is very difficult to diagnose on the basis of a
photographic image.
Persistent remora damage was suggested by several researchers. In
Hawaii, researchers observed an individual young Tursiops with a skin
"rash" that looked like the one in our photo. Each time the animal was
seen, it was with an attached remora. In some remora species at least,
the dorsal sucker disk contains several rows of modified spines that
actually protrude beyond the flesh of the disk, and therefore will
penetrate the skin of the host animal. In the case of the dolphins,
this could cause abrasions of the skin, leading to the apparent rash.
(Good photographic evidence from Hawaii can be found at:
http://www.cascadiaresearch.org/hawaii/OctNov2011.htm
Others suggested the lesion could be caused by Blastomyces spp., a kind
of fungi that is found on stressed (and thus immunodepressed) animals.
Another fungal disease which is contagious to humans is "Lobomycosis",
it shows very similar skin irregularities as seen from the pictures.
Some colleagues also speculated about bacterial infections (e.g. marine
vibrios). **
Still others thought it looks like a trauma-induced condition, i.e. some
type of trauma may have abraded the skin and then an infection, possibly
fungal, may have set in. Again, there would be a relation to reduced
immune function.
Hence, vibrio bacteria, Papillomavirus, Herpesvirus, Morbillivirus and
Poxviruses, or a fungus as well as Parasites could all cause these
lesions. I have to stress that there were divergent valuations about
almost all of these potential causes.
So, as a synthesis, I suggest the following to be the most likely scenario:
After the remora can be clearly seen on the image, and given its
location, the skin of the dolphin may have suffered from its attachment.
We have seen many emaciated dolphins this year and therefore some
individuals probably are stressed by missing feeding opportunities, i.e.
they were prone to immunodepression. In this situation, a damage of the
skin (e.g. by the remora or other causes) has triggered a secondary
infection - either viral, fungal or bacterial or through parasites --
but a definite identification of the eliciting agent is not possible via
photographic images only.
If anyone has additional suggestions, we will be happy to hear them.
Cheers,
Fabian
--
Fabian Ritter
-/President-
M.E.E.R. e.V.
Bundesallee 123
D-12161 Berlin
T/F: (0)30-644 97 230
e-Mail:[email protected]
www.m-e-e-r.org
---
The dolphins were having a great relaxed time
and there were no major answers they wished
to know the questions to...
(After Douglas Adams)
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