[MARMAM] 2007 Ligurian Sea "epidemic": an update

Fulvio Garibaldi garibaldi.f at libero.it
Tue Feb 24 11:12:19 PST 2009

Dear all,
this is just a brief (one year later) update about the striped dolphin stranding events occurred during 2007-2008 in the Ligurian Sea. 
After February 2008 no stranding events that could be supposedly linked, from the spatio-temporal point of view, to the 2006-2007 morbillivirus epidemic in the Mediterranean Sea were recorded. Despite some of the histological lesions with special reference to the brain lesions) observed in these dolphins and some serological findings were interpreted first as the results of a possible morbillivirus infection, the serological, immunohistochemical, indirect immunofluorescence and biomolecular (RT-PCR) investigations subsequently carried out showed that, although morbillivirus exposure probably took place in these animals, the protozoan Toxoplasma gondii was the likely cause of the inflammatory brain lesions (non-suppurative meningo–encephalitis) observed in at least 4 out of the 10 stranded dolphins under study. Therefore, this mortality outbreak among Ligurian Sea striped dolphins was different from those observed between 2006 and 2007 in other Mediterranean Sea areas. 
Another reason of interest is that during 2008 the striped dolphin stranding rate in the Ligurian Sea area was lower than that expected as the normal “plafond” in previous years. This could imply three possible scenarios: 1) the "epidemic" was more consistent than the number of stranded animals could suggest (causing a high population depletion) 2) the “epidemic” behaved as a natural selector for the species involved (striped dolphin), with only non-healthy individuals succumbing to it 3) an alternative explanation could be also that, following repeated exposure to the infectious agent(s) circulating in the area dolphin morbillivirus? Toxoplasma gondii?) a relevant percentage of exposed/susceptible animals developed protective immunity to such pathogens.
This is also to inform you that a poster presentation dealing with these striped dolphin mortality episodes in the Ligurian Sea will be on display at the 23rd ECS Conference in Istanbul next week. 

Best regards

Fulvio Garibaldi, Ph.D
University of Genoa
C.so Europa, 26 - 16132 Genova 
Phone/fax +39 010 357 888
e-mail address: largepel at unige.it
personal e-mail address: garibaldi.f at libero.it

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