Dolphin morbillivirus (dmv) and herpesvirus (hv) co-infection during reemerging striped dolphin mortality (2007) in Mediterranean sea

Abstract

Ten striped dolphins (Stenella coeruleoalba) that stranded during the re-emerging dolphin morbillivirus mortality in the Mediterranean Sea in summer of 2007 (Raga et al., 2008), were studied immunohistochemically and by RT-PCR for detection of Cetacean Morbillivirus (CeMV) and Herpes Virus (HV). All ten dolphins were immunohistochemically and RT-PCR positive for Dolphin Morbillivirus (DMV) and five out of ten were RT-PCR positively co-infected with Herpes Virus (HV). HV infection causing clinical disease in free ranging cetaceans has been rarely reported. Although HV does not seem to have played a principal role in the ethio-pathogenesis of the re-emerging epizootic dolphin mortality that occurred during 2007 in the Mediterranean Sea, its detection merits reference to it as a secondary viral co-infection not described previously during the first striped dolphin epizootic caused by DMV in the Mediterranean Sea (Domingo et al., 1992). All the evidence would support the primary pathogenic role of DMV (Domingo et al., 1992). This immunosuppressive ability of CeMV has been demonstrated «in vitro» by inhibition of lymphocyte proliferation (Heaney et al., 2002). However, during the first striped dolphin epizootic, abnormally high polychlorinated biphenyl levels were detected in those dolphins (Aguilar et al., 1994), raising the question of the role of pollutants as a previous or concomitant condition in the disease break-out. No pollutant data have been published from the last striped dolphin mortality, however. This work reports HV in S. coeruleoalba in the Mediterranean Sea, and new HV sequences not previously described to date.