Genetic heterogeneity of dolphin morbilliviruses detected in the Spanish Mediterranean in inter-epizootic period.

BACKGROUND: In the last 20 years, Cetacean Morbillivirus (CeMV) has been responsible for many die-offs in marine mammals worldwide, as clearly exemplified by the three dolphin morbillivirus (DMV) epizootics of 1990-1992, 2006-2008 and 2011 that affected Mediterranean striped dolphins (Stenella coeruleoalba). Systemic infection caused by DMV in the Mediterranean has been reported only during these outbreaks. RESULTS: We report the infection of five striped dolphins (Stenella coeruleoalba) stranded on the Spanish Mediterranean coast of Valencia after the last DMV outbreak that ended in 2011. Animal 1 stranded in late 2011 and Animal 2 in 2012. Systemic infection affecting all tissues was found based on histopathology and positive immunohistochemical and polymerase chain reaction positive results. Animal 3 stranded in 2014; molecular and immunohistochemical detection was positive only in the central nervous system. Animals 4 and 5 stranded in 2015, and DMV antigen was found in several tissues. Partial sequences of the DMV phosphoprotein (P), nucleoprotein (N), and hemagglutinin (H) genes were identical for Animals 2, 3, 4, and 5, and were remarkably different from those in Animal 1. The P sequence from Animal 1 was identical to that of the DMV strain that caused the epizootic of 2011 in the Spanish Mediterranean. The corresponding sequence from Animals 2-5 was identical to that from a striped dolphin stranded in 2011 on the Canary Islands and to six dolphins stranded in northeastern Atlantic of the Iberian Peninsula. CONCLUSIONS: These results suggest the existence of an endemic infection cycle among striped dolphins in the Mediterranean that may lead to occasional systemic disease presentations outside epizootic periods. This cycle involves multiple pathogenic viral strains, one of which may have originated in the Atlantic Ocean.

Herpes virus infection associated with interstitial nephritis in a beaked whale (Mesoplodon densirostris).

BACKGROUND: The capacity for herpesvirus to cause disease in cetaceans is unclear and may be varied depending on the different conditions of individuals and between different species. Kidney pathology and intralesional virus-associated infection have been rarely reported in cetaceans. RESULT: On April 2004, an old adult male Blainville's beaked whale (Mesoplodon densirostris) 420 cm long with a poor body condition was stranded on Tenerife Island. During necropsy, no gross lesions were observed in the kidneys. However, membranous glomerulonephritis, multifocal interstitial lymphoplasmacytic nephritis and acute multifocal necrotizing tubulointerstitial nephritis with intranuclear inclusion bodies was diagnosed by histological analysis. Tissue samples were submitted for bacteriological analysis and molecular viral screening. CONCLUSION: A novel alpha herpesvirus associated with interstitial nephritis was identified in an old adult male Blainville's beaked whale (M. densirostris) with a poor body condition stranded in the Canary Islands. This report suggests that identification of herpesvirus infection could be used as a differential diagnosis for interstitial nephritis in cetaceans.

Herpesvirus infection with severe lymphoid necrosis affecting a beaked whale stranded in the Canary Islands.

This report describes the pathologic findings in a single, adult female Cuvier's beaked whale Ziphius cavirostris stranded in the Canary Islands. The study indicated that this whale died with a severe, systemic, herpesviral infection and clearly exhibited lesions different from those of the fat and gas embolic syndrome described in beaked whale mass strandings associated with sonar exposure. This is the first report of a cetacean alphaherpesvirus infection of the lymphoid system in a beaked whale.

Presence of herpesvirus in striped dolphins stranded during the cetacean morbillivirus epizootic along the Mediterranean Spanish coast in 2007.

A screening for herpesvirus (HV) was carried out using a tissue bank obtained from the cetacean morbillivirus (CeMV) mortality episode that occurred along the Mediterranean Spanish coast in 2007. A total of 14 cetaceans, including six long-finned pilot whales and eight striped dolphins, were studied using histopathology and molecular analysis to detect HV and CeMV. In five of the eight dolphins (62.5%) infected with CeMV, eight novel HV sequences were also detected. No HV lesions were found in any of the coinfected dolphins, which may indicate that HV did not contribute to the mortality in the CeMV outbreak. This is the first report of HV infection in any cetacean from the Mediterranean Sea.